diagnostics(query): trace interruption causality (#2111)

* diagnostics(issue-1830): trace interruption causality

* test(issue-1830): lock interruption ownership matrix

* fix(codex): preserve stream deadline contract

* fix(diagnostics): harden interruption trace lifecycle

Refs #1830

* fix(diagnostics): harden interruption trace settlement

Refs #1830

* fix(diagnostics): preserve interruption causality

* fix(diagnostics): address interruption trace review

* fix(diagnostics): preserve tracing observer contracts

* fix(diagnostics): preserve interruption trace contracts

* test(permissions): cover interactive hook interrupts

docs/advanced-setup.md

@@ -481,6 +481,8 @@ host. Without this variable the behavior is unchanged.
 | `OPENCLAUDE_MAX_TURNS` | No | Per-prompt **local** interactive REPL turn cap for the in-process query loop. Defaults to `50`. Set a larger positive integer for long autonomous local interactive sessions (for example models that take many small tool steps). CLI `--max-turns 0` explicitly disables this cap and prints a cautionary warning. Precedence for a valid override: CLI `--max-turns` → this env var → legacy `CLAUDE_CODE_MAX_TURNS` (only when this var is unset/empty) → `/config` → Max turns (interactive) → `50`. If this env var is set but invalid (zero, negative, non-integer), the default `50` is used and lower layers are not consulted — same pattern as `OPENCLAUDE_MAX_RETRIES`. Does not apply to remote-backed interactive sessions (`connect` / `ssh` / `--remote`). |
 | `OPENCLAUDE_RETRY_DELAY_MS` | No | Base retry delay in milliseconds for APIs that do not send `Retry-After`; exponential backoff starts from this value, capped at 60000 (default: 500) |
 | `OPENCLAUDE_QUERY_HARD_MAX_MS` | No | Foreground query hard maximum in milliseconds. Defaults to 1800000 (30 minutes). Use a larger positive integer for long autonomous sessions; invalid, zero, negative, fractional, or timer-overflow values are ignored with a warning. |
+| `OPENCLAUDE_INTERRUPT_TRACE` | No | Set to `1` or `true` to retain a bounded, privacy-safe interruption lifecycle trace in memory. Disabled by default. The trace contains only allowlisted lifecycle metadata—never prompts, responses, tool arguments, credentials, or raw error messages. |
+| `OPENCLAUDE_INTERRUPT_TRACE_FILE` | No | Optional absolute JSONL output path used only when `OPENCLAUDE_INTERRUPT_TRACE` is enabled. On Linux, missing parent directories are created privately and every parent is opened through `/proc/self/fd` without following symbolic links before the final regular file is appended. If the file already exists, its mode is reset to `0600` on every append, so do not configure a shared file. Other platforms retain the bounded trace in memory but do not write this file because Node does not expose an equivalent safe descriptor-relative traversal API there. Writes are best-effort and never change request behavior. Use a separate path per OpenClaude process and keep the resulting diagnostic file private. |
 | `OPENCLAUDE_DISABLE_CO_AUTHORED_BY` | No | Suppress the default `Co-Authored-By` trailer in generated git commits |
 | `OPENCLAUDE_LOG_TOKEN_USAGE` | No | When truthy (e.g. `verbose`), emits one JSON line on stderr per API request with input/output/cache tokens and the resolved provider. **User-facing debug output** — complements the REPL display controlled by `/config showCacheStats`. Distinct from `CLAUDE_CODE_ENABLE_TOKEN_USAGE_ATTACHMENT`, which is **model-facing** (injects context usage info into the prompt itself). Both can run together. |
 

src/QueryEngine.interruptionTrace.test.ts

@@ -0,0 +1,183 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from './test/sharedMutationLock.js'
+import { QueryEngine } from './QueryEngine.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  registerInterruptionController,
+} from './utils/interruptionTrace.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('QueryEngine.interruptionTrace.test.ts')
+})
+
+afterEach(async () => {
+  try {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+describe('QueryEngine interruption tracing', () => {
+  test('does not record lifecycle entries while tracing is disabled', async () => {
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    const engine = Object.create(QueryEngine.prototype) as QueryEngine
+    const controller = new AbortController()
+    ;(engine as unknown as { abortController: AbortController }).abortController =
+      controller
+    ;(engine as unknown as {
+      submitMessageImpl(): AsyncGenerator<never, void, unknown>
+    }).submitMessageImpl = async function* () {}
+
+    for await (const _message of engine.submitMessage('hello')) {
+      // The stub deliberately yields nothing.
+    }
+
+    expect(__getInterruptionTraceSnapshotForTests()).toEqual([])
+  })
+
+  test('records a programmatic query-root interruption before aborting', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const controller = new AbortController()
+    const engine = Object.create(QueryEngine.prototype) as QueryEngine
+    ;(engine as unknown as {
+      abortController: AbortController
+    }).abortController = controller
+
+    engine.interrupt('sdk_interrupt')
+
+    const requested = __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'abort.requested',
+    )
+    expect(controller.signal.aborted).toBe(true)
+    expect(requested).toMatchObject({
+      source: 'sdk_interrupt',
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
+  })
+
+  test('records start and terminal lifecycle for successful SDK turns', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const engine = Object.create(QueryEngine.prototype) as QueryEngine
+    const controller = new AbortController()
+    ;(engine as unknown as { abortController: AbortController }).abortController =
+      controller
+    ;(engine as unknown as {
+      submitMessageImpl(): AsyncGenerator<never, void, unknown>
+    }).submitMessageImpl = async function* () {}
+
+    for await (const _message of engine.submitMessage('hello')) {
+      // The stub deliberately yields nothing.
+    }
+
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const started = trace.find(entry => entry.event === 'query.started')
+    const terminal = trace.find(entry => entry.event === 'query.terminal')
+    expect(started).toMatchObject({
+      subsystem: 'query_engine',
+      querySource: 'sdk',
+      controllerRole: 'query-root',
+    })
+    expect(terminal).toMatchObject({
+      subsystem: 'query_engine',
+      queryId: started?.queryId,
+      outcome: 'completed',
+    })
+    expect(typeof started?.eventId).toBe('string')
+    expect(typeof terminal?.causalEventId).toBe('string')
+    expect(terminal!.causalEventId).toBe(started!.eventId)
+  })
+
+  test('records aborted and failed SDK turn terminals', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+
+    for (const scenario of ['aborted', 'failed'] as const) {
+      __resetInterruptionTraceForTests()
+      const engine = Object.create(QueryEngine.prototype) as QueryEngine
+      const controller = new AbortController()
+      ;(engine as unknown as { abortController: AbortController }).abortController =
+        controller
+      ;(engine as unknown as {
+        submitMessageImpl(): AsyncGenerator<never, void, unknown>
+      }).submitMessageImpl = async function* () {
+        if (scenario === 'aborted') {
+          controller.abort('interrupt')
+          return
+        }
+        throw new Error('turn failed')
+      }
+
+      const drain = async () => {
+        for await (const _message of engine.submitMessage('hello')) {
+          // The stub deliberately yields nothing.
+        }
+      }
+      if (scenario === 'failed') await expect(drain()).rejects.toThrow('turn failed')
+      else await drain()
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const started = trace.find(entry => entry.event === 'query.started')
+      const terminal = trace.find(entry => entry.event === 'query.terminal')
+      expect(terminal?.outcome).toBe(scenario)
+      expect(typeof started?.eventId).toBe('string')
+      expect(typeof terminal?.eventId).toBe('string')
+      if (scenario === 'aborted') {
+        const observed = trace.find(
+          entry => entry.event === 'signal.observed',
+        )
+        expect(typeof observed?.eventId).toBe('string')
+        expect(terminal?.causalEventId).toBe(observed!.eventId)
+      } else {
+        expect(terminal?.causalEventId).toBe(started!.eventId)
+      }
+    }
+  })
+
+  test('registers the query root when tracing is enabled at the turn boundary', async () => {
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    const engine = Object.create(QueryEngine.prototype) as QueryEngine
+    const controller = new AbortController()
+    ;(engine as unknown as { abortController: AbortController }).abortController =
+      controller
+    registerInterruptionController(controller, {
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    ;(engine as unknown as {
+      submitMessageImpl(): AsyncGenerator<never, void, unknown>
+    }).submitMessageImpl = async function* () {
+      controller.abort()
+    }
+
+    for await (const _message of engine.submitMessage('hello')) {
+      // The stub deliberately yields nothing.
+    }
+
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const registered = trace.find(
+      entry =>
+        entry.event === 'controller.registered' &&
+        entry.controllerRole === 'query-root',
+    )
+    const observed = trace.find(entry => entry.event === 'signal.observed')
+    const terminal = trace.find(entry => entry.event === 'query.terminal')
+    expect(registered).toBeDefined()
+    expect(typeof observed?.eventId).toBe('string')
+    expect(terminal).toMatchObject({
+      outcome: 'aborted',
+      causalEventId: observed!.eventId,
+    })
+  })
+})

src/QueryEngine.ts

@@ -45,6 +45,14 @@ import { SYNTHETIC_OUTPUT_TOOL_NAME } from './tools/SyntheticOutputTool/Syntheti
 import type { Message } from './types/message.js'
 import type { OrphanedPermission } from './types/textInputTypes.js'
 import { createAbortController } from './utils/abortController.js'
+import {
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  isInterruptionTraceEnabled,
+  registerInterruptionController,
+  requestAbort,
+  traceInterruptionEvent,
+} from './utils/interruptionTrace.js'
 import { validateArrayOf, assertNonEmptyString, assertObject, assertFunction } from './utils/validation.js'
 import { invalidateRemovedToolSchemas } from './utils/toolSchemaCache.js'
 import type { AttributionState } from './utils/commitAttribution.js'
@@ -205,6 +213,10 @@ export class QueryEngine {
     this.config = config
     this.mutableMessages = config.initialMessages ?? []
     this.abortController = config.abortController ?? createAbortController()
+    registerInterruptionController(this.abortController, {
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
     this.permissionDenials = []
     this.readFileState = config.readFileCache
     this.totalUsage = EMPTY_USAGE
@@ -213,6 +225,56 @@ export class QueryEngine {
   async *submitMessage(
     prompt: string | ContentBlockParam[],
     options?: { uuid?: string; isMeta?: boolean },
+  ): AsyncGenerator<SDKMessage, void, unknown> {
+    const queryId = isInterruptionTraceEnabled() ? randomUUID() : undefined
+    registerInterruptionController(this.abortController, {
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+      queryId,
+      querySource: 'sdk',
+    }, { refreshQueryContext: true })
+    const startedEventId = traceInterruptionEvent('query.started', {
+      subsystem: 'query_engine',
+      phase: 'running',
+      queryId,
+      querySource: 'sdk',
+      controllerRole: 'query-root',
+    })
+    let outcome = 'consumer_closed'
+    let terminalError: unknown
+    try {
+      yield* this.submitMessageImpl(prompt, options)
+      outcome = this.abortController.signal.aborted ? 'aborted' : 'completed'
+    } catch (error) {
+      terminalError = error
+      outcome = this.abortController.signal.aborted ? 'aborted' : 'failed'
+      throw error
+    } finally {
+      const terminalOutcome = this.abortController.signal.aborted
+        ? 'aborted'
+        : outcome
+      traceInterruptionEvent('query.terminal', {
+        subsystem: 'query_engine',
+        phase: terminalOutcome,
+        queryId,
+        querySource: 'sdk',
+        controllerRole: 'query-root',
+        outcome: terminalOutcome,
+        reason: this.abortController.signal.reason,
+        error: terminalError,
+        causalEventId: terminalOutcome === 'aborted'
+          ? getInterruptionSignalAbortEventId(this.abortController.signal)
+          : startedEventId,
+      })
+      if (this.abortController.signal.aborted) {
+        flushInterruptionTrace('query_terminal')
+      }
+    }
+  }
+
+  private async *submitMessageImpl(
+    prompt: string | ContentBlockParam[],
+    options?: { uuid?: string; isMeta?: boolean },
   ): AsyncGenerator<SDKMessage, void, unknown> {
     const {
       cwd,
@@ -1212,8 +1274,12 @@ export class QueryEngine {
     }
   }
 
-  interrupt(): void {
+  interrupt(source = 'programmatic_interrupt'): void {
-    this.abortController.abort()
+    requestAbort(this.abortController, undefined, {
+      source,
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
   }
 
   getMessages(): readonly Message[] {

src/cli/print.interruptionTrace.test.ts

@@ -0,0 +1,108 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../utils/interruptionTrace.js'
+import {
+  abortPrintModeControlRequest,
+  type PrintModeControlAbortSource,
+} from './printInterruption.js'
+
+const originalInterruptionTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+let hasSharedMutationLock = false
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('cli/print.interruptionTrace.test.ts')
+  hasSharedMutationLock = true
+})
+
+afterEach(async () => {
+  try {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalInterruptionTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalInterruptionTrace
+    }
+  } finally {
+    if (hasSharedMutationLock) {
+      releaseSharedMutationLock()
+      hasSharedMutationLock = false
+    }
+  }
+})
+
+describe('print-mode interruption tracing', () => {
+  test.each([
+    ['sdk_control_interrupt', 'interrupt'],
+    ['sdk_end_session', undefined],
+  ] as const)(
+    'links %s input to the query and speculation aborts',
+    (source: PrintModeControlAbortSource, queryReason: unknown) => {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+      __resetInterruptionTraceForTests()
+      const queryController = new AbortController()
+      const suggestionController = new AbortController()
+
+      const causalEventId = abortPrintModeControlRequest(
+        queryController,
+        suggestionController,
+        source,
+        queryReason,
+      )
+
+      expect(queryController.signal.aborted).toBe(true)
+      expect(suggestionController.signal.aborted).toBe(true)
+      const trace = __getInterruptionTraceSnapshotForTests()
+      expect(trace.find(entry => entry.eventId === causalEventId)).toMatchObject({
+        event: `input.${source}`,
+        source,
+        subsystem: 'print_mode',
+      })
+      expect(
+        trace.find(
+          entry =>
+            entry.event === 'abort.requested' &&
+            entry.controllerRole === 'query-root',
+        ),
+      ).toMatchObject({ source, causalEventId, subsystem: 'print_mode' })
+      expect(
+        trace.find(
+          entry =>
+            entry.event === 'abort.requested' &&
+            entry.controllerRole === 'speculation',
+        ),
+      ).toMatchObject({
+        source,
+        causalEventId,
+        subsystem: 'prompt_suggestion',
+      })
+    },
+  )
+
+  test('preserves native abort behavior when tracing is disabled', () => {
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    __resetInterruptionTraceForTests()
+    const queryController = new AbortController()
+    const suggestionController = new AbortController()
+
+    const causalEventId = abortPrintModeControlRequest(
+      queryController,
+      suggestionController,
+      'sdk_control_interrupt',
+      'interrupt',
+    )
+
+    expect(causalEventId).toBeUndefined()
+    expect(queryController.signal.reason).toBe('interrupt')
+    expect(suggestionController.signal.reason).toBeInstanceOf(DOMException)
+    expect(suggestionController.signal.reason.name).toBe('AbortError')
+    expect(__getInterruptionTraceSnapshotForTests()).toEqual([])
+  })
+})

src/cli/print.ts

@@ -148,6 +148,10 @@ import {
   permissionPromptToolResultToPermissionDecision,
 } from 'src/utils/permissions/PermissionPromptToolResultSchema.js'
 import { createAbortController } from 'src/utils/abortController.js'
+import {
+  registerInterruptionController,
+  requestAbort,
+} from 'src/utils/interruptionTrace.js'
 import { createCombinedAbortSignal } from 'src/utils/combinedAbortSignal.js'
 import {
   generateSessionTitle,
@@ -348,6 +352,7 @@ import {
   type HeadlessHeartbeatEvent,
   type HeadlessHeartbeatState,
 } from './headlessHeartbeat.js'
+import { abortPrintModeControlRequest } from './printInterruption.js'
 import {
   isTeamLead,
   hasActiveInProcessTeammates,
@@ -1204,6 +1209,14 @@ function runHeadlessStreaming(
   let shutdownPromptInjected = false
   let heldBackResult: StdoutMessage | null = null
   let abortController: AbortController | undefined
+  const abortActiveQuery = (source: string, reason: unknown): void => {
+    if (!abortController || abortController.signal.aborted) return
+    requestAbort(abortController, reason, {
+      source,
+      subsystem: 'print_mode',
+      controllerRole: 'query-root',
+    })
+  }
   // Same queue sendRequest() enqueues to — one FIFO for everything.
   const output = structuredIO.outbound
 
@@ -1213,9 +1226,7 @@ function runHeadlessStreaming(
   const sigintHandler = () => {
     logForDiagnosticsNoPII('info', 'shutdown_signal', { signal: 'SIGINT' })
     options.heartbeat?.setPhase('shutting_down')
-    if (abortController && !abortController.signal.aborted) {
+    abortActiveQuery('print_sigint', 'interrupt')
-      abortController.abort('interrupt')
-    }
     void gracefulShutdown(0)
   }
   process.on('SIGINT', sigintHandler)
@@ -2044,7 +2055,7 @@ function runHeadlessStreaming(
   // Abort the current operation when a 'now' priority message arrives.
   subscribeToCommandQueue(() => {
     if (abortController && getCommandsByMaxPriority('now').length > 0) {
-      abortController.abort('interrupt')
+      abortActiveQuery('priority_now', 'interrupt')
     }
   })
 
@@ -2318,6 +2329,10 @@ function runHeadlessStreaming(
           }
 
           abortController = createAbortController()
+          registerInterruptionController(abortController, {
+            subsystem: 'print_mode',
+            controllerRole: 'query-root',
+          })
           const turnStartTime = feature('FILE_PERSISTENCE')
             ? Date.now()
             : undefined
@@ -3029,10 +3044,12 @@ function runHeadlessStreaming(
               },
             }))
           }
-          if (abortController) {
+          abortPrintModeControlRequest(
-            abortController.abort('interrupt')
+            abortController,
-          }
+            suggestionState.abortController,
-          suggestionState.abortController?.abort()
+            'sdk_control_interrupt',
+            'interrupt',
+          )
           suggestionState.abortController = null
           suggestionState.lastEmitted = null
           suggestionState.pendingSuggestion = null
@@ -3041,10 +3058,12 @@ function runHeadlessStreaming(
           logForDebugging(
             `[print.ts] end_session received, reason=${message.request.reason ?? 'unspecified'}`,
           )
-          if (abortController) {
+          abortPrintModeControlRequest(
-            abortController.abort()
+            abortController,
-          }
+            suggestionState.abortController,
-          suggestionState.abortController?.abort()
+            'sdk_end_session',
+            undefined,
+          )
           suggestionState.abortController = null
           suggestionState.lastEmitted = null
           suggestionState.pendingSuggestion = null
@@ -4127,7 +4146,7 @@ function runHeadlessStreaming(
                     structuredIO.injectControlResponse(response)
                   },
                   onInterrupt() {
-                    abortController?.abort('interrupt')
+                    abortActiveQuery('bridge_interrupt', 'interrupt')
                   },
                   onSetModel(model) {
                     const resolved =

src/cli/printInterruption.ts

@@ -0,0 +1,37 @@
+import {
+  requestAbort,
+  traceInterruptionEvent,
+} from '../utils/interruptionTrace.js'
+
+export type PrintModeControlAbortSource =
+  | 'sdk_control_interrupt'
+  | 'sdk_end_session'
+
+export function abortPrintModeControlRequest(
+  queryController: AbortController | undefined,
+  suggestionController: AbortController | null,
+  source: PrintModeControlAbortSource,
+  queryReason: unknown,
+): string | undefined {
+  const causalEventId = traceInterruptionEvent(`input.${source}`, {
+    source,
+    subsystem: 'print_mode',
+  })
+  if (queryController && !queryController.signal.aborted) {
+    requestAbort(queryController, queryReason, {
+      source,
+      causalEventId,
+      subsystem: 'print_mode',
+      controllerRole: 'query-root',
+    })
+  }
+  if (suggestionController && !suggestionController.signal.aborted) {
+    requestAbort(suggestionController, undefined, {
+      source,
+      causalEventId,
+      subsystem: 'prompt_suggestion',
+      controllerRole: 'speculation',
+    })
+  }
+  return causalEventId
+}

src/components/permissions/MonitorPermissionRequest/MonitorPermissionRequest.test.tsx

@@ -34,6 +34,11 @@ import type {
 } from '../../../utils/permissions/PermissionResult.js'
 import type { PermissionUpdate } from '../../../utils/permissions/PermissionUpdateSchema.js'
 import type { ToolUseConfirm } from '../PermissionRequest.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../../../utils/interruptionTrace.js'
 
 function createTestStreams(): {
   stdout: PassThrough
@@ -344,6 +349,8 @@ async function renderMonitorPermission(
   }
 }
 
+const originalInterruptionTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
 beforeEach(async () => {
   await acquireSharedMutationLock(
     'components/permissions/MonitorPermissionRequest.test.tsx',
@@ -353,9 +360,16 @@ beforeEach(async () => {
   }))
 })
 
-afterEach(() => {
+afterEach(async () => {
   try {
     mock.restore()
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalInterruptionTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalInterruptionTrace
+    }
   } finally {
     releaseSharedMutationLock()
   }
@@ -486,6 +500,8 @@ describe('MonitorPermissionRequest', () => {
   })
 
   test('escape cancels the pending permission request and closes the dialog', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
     const onDone = mock(() => {})
     const onReject = mock(() => {})
     const { toolUseConfirm, toolUseContext, decisionPromise } =
@@ -504,6 +520,16 @@ describe('MonitorPermissionRequest', () => {
       expect(decision.behavior).toBe('ask')
       expect(toolUseContext.abortController.signal.aborted).toBe(true)
       expect(onReject).toHaveBeenCalledTimes(1)
+      expect(
+        __getInterruptionTraceSnapshotForTests().find(
+          entry =>
+            entry.event === 'abort.requested' &&
+            entry.source === 'permission_abort',
+        ),
+      ).toMatchObject({
+        subsystem: 'tool_permission',
+        controllerRole: 'query-root',
+      })
     } finally {
       mounted.cleanup()
     }

src/components/permissions/PermissionRequest.tsx

@@ -120,7 +120,7 @@ export type ToolUseConfirm<Input extends AnyObject = AnyObject> = {
   classifierMatchedRule?: string;
   workerBadge?: WorkerBadgeProps;
   onUserInteraction(): void;
-  onAbort(): void;
+  onAbort(source?: string, causalEventId?: string): void;
   onDismissCheckmark?(): void;
   onAllow(updatedInput: z.infer<Input>, permissionUpdates: PermissionUpdate[], feedback?: string, contentBlocks?: ContentBlockParam[]): void;
   onReject(feedback?: string, contentBlocks?: ContentBlockParam[]): void;

src/entrypoints/sdk/interruption.ts

@@ -0,0 +1,14 @@
+import { requestAbort } from '../../utils/interruptionTrace.js'
+
+export function requestSdkRootAbort(
+  controller: AbortController,
+  source: string,
+  subsystem: 'sdk_query' | 'sdk_session',
+): void {
+  if (controller.signal.aborted) return
+  requestAbort(controller, undefined, {
+    source,
+    subsystem,
+    controllerRole: 'query-root',
+  })
+}

src/entrypoints/sdk/query.ts

@@ -20,6 +20,7 @@ import {
 } from '../../Tool.js'
 import { assembleToolPool, getTools } from '../../tools.js'
 import { createFileStateCacheWithSizeLimit } from '../../utils/fileStateCache.js'
+import { requestSdkRootAbort } from './interruption.js'
 import { init } from '../init.js'
 import {
   resolveSessionFilePath,
@@ -756,8 +757,9 @@ class QueryImpl implements Query {
   }
 
   close(): void {
-    this.interrupt()
+    const wrapperController = this.abortController
-    this.abortController.abort()
+    this.interruptWithSource('sdk_close')
+    requestSdkRootAbort(wrapperController, 'sdk_close', 'sdk_query')
     // Disconnect MCP clients to prevent resource leaks
     const mcpClients = this._engine?.getMcpClients?.() ?? []
     for (const client of mcpClients) {
@@ -773,8 +775,14 @@ class QueryImpl implements Query {
   }
 
   interrupt(): void {
+    this.interruptWithSource('sdk_interrupt')
+  }
+
+  private interruptWithSource(source: string): void {
     if (this._engine) {
-      this._engine.interrupt()
+      this._engine.interrupt(source)
+    } else {
+      requestSdkRootAbort(this.abortController, source, 'sdk_query')
     }
     // Deny all pending permission prompts before clearing
     for (const [toolUseId, pending] of this.pendingPermissionPrompts) {

src/entrypoints/sdk/v2.ts

@@ -19,6 +19,7 @@ import {
 } from '../../Tool.js'
 import { assembleToolPool, getTools } from '../../tools.js'
 import { createFileStateCacheWithSizeLimit } from '../../utils/fileStateCache.js'
+import { requestSdkRootAbort } from './interruption.js'
 import { init } from '../init.js'
 import {
   resolveSessionFilePath,
@@ -387,8 +388,14 @@ class SDKSessionImpl implements SDKSession {
   }
 
   interrupt(): void {
+    this.interruptWithSource('sdk_interrupt')
+  }
+
+  private interruptWithSource(source: string): void {
     if (this._engine) {
-      this._engine.interrupt()
+      this._engine.interrupt(source)
+    } else if (this._abortController) {
+      requestSdkRootAbort(this._abortController, source, 'sdk_session')
     }
     // Deny all pending permission prompts before clearing
     for (const [toolUseId, pending] of this.pendingPermissionPrompts) {
@@ -403,10 +410,11 @@ class SDKSessionImpl implements SDKSession {
   }
 
   close(): void {
-    this.interrupt()
+    const wrapperController = this._abortController
-    // Abort the AbortController to cancel any in-flight HTTP requests or
+    this.interruptWithSource('sdk_close')
-    // async operations tied to the signal. Mirrors QueryImpl.close().
+    if (wrapperController) {
-    this._abortController?.abort()
+      requestSdkRootAbort(wrapperController, 'sdk_close', 'sdk_session')
+    }
     this._abortController = null
     // Disconnect MCP clients to prevent resource leaks
     const mcpClients = this._engine?.getMcpClients?.() ?? []

src/grpc/server.interruptionTrace.test.ts

@@ -0,0 +1,89 @@
+import { EventEmitter } from 'node:events'
+import { expect, spyOn, test } from 'bun:test'
+import { QueryEngine } from '../QueryEngine.js'
+import { GrpcServer } from './server.js'
+
+class FakeCall extends EventEmitter {
+  writes: unknown[] = []
+  ended = false
+
+  write(value: unknown): void {
+    this.writes.push(value)
+  }
+
+  end(): void {
+    this.ended = true
+  }
+}
+
+async function exerciseInterruption(
+  event: 'cancel' | 'end',
+): Promise<string | undefined> {
+  let releaseSubmit!: () => void
+  const submitBlocked = new Promise<void>(resolve => {
+    releaseSubmit = resolve
+  })
+  let submitEntered = false
+  const submitMessage = spyOn(
+    QueryEngine.prototype,
+    'submitMessage',
+  ).mockImplementation(
+    async function* () {
+      submitEntered = true
+      await submitBlocked
+    },
+  )
+  const interrupt = spyOn(QueryEngine.prototype, 'interrupt')
+  try {
+    const server = new GrpcServer()
+    const call = new FakeCall()
+    ;(server as unknown as {
+      handleChat(call: FakeCall): void
+    }).handleChat(call)
+    call.emit('data', {
+      request: {
+        message: 'test',
+        working_directory: process.cwd(),
+        model: 'sonnet',
+      },
+    })
+    let interruptionEmitted = false
+    for (
+      let attempts = 0;
+      attempts < 100 && interrupt.mock.calls.length === 0;
+      attempts++
+    ) {
+      if (event === 'cancel' && submitEntered && !interruptionEmitted) {
+        call.emit('data', { cancel: {} })
+        interruptionEmitted = true
+      }
+      if (event === 'end' && submitEntered && !interruptionEmitted) {
+        call.emit('end')
+        interruptionEmitted = true
+      }
+      await Bun.sleep(10)
+    }
+    if (!submitEntered) {
+      throw new Error('submitMessage was never entered')
+    }
+    if (interrupt.mock.calls.length === 0) {
+      throw new Error(
+        `Timed out waiting for QueryEngine.interrupt after the '${event}' event`,
+      )
+    }
+    return interrupt.mock.calls[0]?.[0]
+  } finally {
+    releaseSubmit()
+    await Bun.sleep(10)
+    interrupt.mockRestore()
+    submitMessage.mockRestore()
+  }
+}
+
+test('labels an explicit gRPC cancellation', async () => {
+  expect(await exerciseInterruption('cancel')).toBe('grpc_cancel')
+})
+
+test('labels a gRPC stream ending while a query is active', async () => {
+  expect(await exerciseInterruption('end')).toBe('grpc_stream_end')
+})

src/grpc/server.ts

@@ -289,7 +289,7 @@ export class GrpcServer {
         } else if (clientMessage.cancel) {
           interrupted = true
           if (engine) {
-            engine.interrupt()
+            engine.interrupt('grpc_cancel')
           }
           call.end()
         }
@@ -312,7 +312,7 @@ export class GrpcServer {
         resolve('no')
       }
       if (engine) {
-        engine.interrupt()
+        engine.interrupt('grpc_stream_end')
       }
       engine = null
       pendingRequests.clear()

src/hooks/toolPermission/PermissionContext.ts

@@ -22,6 +22,7 @@ import type {
 } from '../../types/permissions.js'
 import { setClassifierApproval } from '../../utils/classifierApprovals.js'
 import { logForDebugging } from '../../utils/debug.js'
+import { requestAbort } from '../../utils/interruptionTrace.js'
 import { executePermissionRequestHooks } from '../../utils/hooks.js'
 import {
   REJECT_MESSAGE,
@@ -210,6 +211,7 @@ function createPermissionContext(
       feedback?: string,
       isAbort?: boolean,
       contentBlocks?: ContentBlockParam[],
+      abortTrace?: { source: string; causalEventId?: string },
     ): PermissionDecision {
       const sub = !!toolUseContext.agentId
       const baseMessage = feedback
@@ -222,7 +224,12 @@ function createPermissionContext(
         logForDebugging(
           `Aborting: tool=${tool.name} isAbort=${isAbort} hasFeedback=${!!feedback} isSubagent=${sub}`,
         )
-        toolUseContext.abortController.abort('interrupt')
+        requestAbort(toolUseContext.abortController, 'interrupt', {
+          source: abortTrace?.source ?? 'permission_abort',
+          causalEventId: abortTrace?.causalEventId,
+          subsystem: 'tool_permission',
+          controllerRole: 'query-root',
+        })
       }
       return { behavior: 'ask', message, contentBlocks }
     },
@@ -367,7 +374,11 @@ function createPermissionContext(
               logForDebugging(
                 `Hook interrupt: tool=${tool.name} hookMessage=${decision.message}`,
               )
-              toolUseContext.abortController.abort('interrupt')
+              requestAbort(toolUseContext.abortController, 'interrupt', {
+                source: 'permission_hook',
+                subsystem: 'tool_permission',
+                controllerRole: 'query-root',
+              })
             }
             return this.buildDeny(
               decision.message || 'Permission denied by hook',

src/hooks/toolPermission/handlers/interactiveHandler.test.ts

@@ -1,4 +1,10 @@
 import { describe, expect, test, vi } from 'vitest'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  requestAbort,
+} from '../../../utils/interruptionTrace.js'
 import {
   handleInteractivePermission,
   type InteractivePermissionParams,
@@ -9,7 +15,7 @@ import {
 // bypasses resolveOnce fails here instead of silently stranding the watchdog.
 
 type QueueItem = {
-  onAbort: () => void
+  onAbort: (source?: string, causalEventId?: string) => void
   onAllow: (
     updatedInput: Record<string, unknown>,
     permissionUpdates: unknown[],
@@ -118,10 +124,19 @@ describe('handleInteractivePermission watchdog suspension', () => {
   })
 
   test('resumes exactly once on abort', () => {
-    const { getQueueItem, resume, resolve } = setup()
+    const { ctx, getQueueItem, resume, resolve } = setup()
-    getQueueItem().onAbort()
+    getQueueItem().onAbort('cancel_keybinding', 'input-event-1')
     expect(resume).toHaveBeenCalledTimes(1)
     expect(resolve).toHaveBeenCalledTimes(1)
+    expect(ctx.cancelAndAbort).toHaveBeenCalledWith(
+      undefined,
+      true,
+      undefined,
+      {
+        source: 'cancel_keybinding',
+        causalEventId: 'input-event-1',
+      },
+    )
   })
 
   test('resumes only once when two resolution paths race', async () => {
@@ -166,6 +181,55 @@ describe('handleInteractivePermission watchdog suspension', () => {
     expect(ctx.removeFromQueue).toHaveBeenCalledTimes(1)
   })
 
+  test('preserves the originating trace when an external abort closes the dialog', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const { ctx, abortController } = setup()
+
+    try {
+      requestAbort(abortController, undefined, {
+        source: 'cancel_keybinding',
+        subsystem: 'query_engine',
+        controllerRole: 'query-root',
+      })
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const originatingAbort = trace.find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'cancel_keybinding',
+      )
+      const permissionResolution = trace.find(
+        entry => entry.event === 'permission.abort_resolved',
+      )
+      expect(typeof originatingAbort?.eventId).toBe('string')
+      expect(permissionResolution).toMatchObject({
+        source: 'cancel_keybinding',
+        subsystem: 'tool_permission',
+        causalEventId: originatingAbort!.eventId,
+        outcome: 'denied',
+      })
+      expect(ctx.cancelAndAbort).toHaveBeenCalledWith(
+        undefined,
+        true,
+        undefined,
+        {
+          source: 'cancel_keybinding',
+          causalEventId: originatingAbort!.eventId,
+        },
+      )
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
   test('resolves and resumes immediately if already aborted when shown', () => {
     const { ctx, resume, resolve } = setup({ preAbort: true })
     expect(resume).toHaveBeenCalledTimes(1)

src/hooks/toolPermission/handlers/interactiveHandler.ts

@@ -27,6 +27,10 @@ import { errorMessage } from '../../../utils/errors.js'
 import type { PermissionDecision } from '../../../utils/permissions/PermissionResult.js'
 import type { PermissionUpdate } from '../../../utils/permissions/PermissionUpdateSchema.js'
 import { hasPermissionsToUseTool } from '../../../utils/permissions/permissions.js'
+import {
+  getInterruptionSignalAbortTrace,
+  tracePermissionAbortResolution,
+} from '../../../utils/interruptionTrace.js'
 import type { PermissionContext } from '../PermissionContext.js'
 import { createResolveOnce } from '../PermissionContext.js'
 
@@ -127,12 +131,23 @@ function handleInteractivePermission(
     const abortSignal = ctx.toolUseContext.abortController.signal
     const onExternalAbort = () => {
       if (!claim()) return
+      const abortTrace = getInterruptionSignalAbortTrace(abortSignal)
+      tracePermissionAbortResolution(
+        abortTrace.source,
+        abortTrace.causalEventId,
+        'tool_permission',
+      )
       if (bridgeCallbacks && bridgeRequestId) {
         bridgeCallbacks.cancelRequest(bridgeRequestId)
       }
       channelUnsubscribe?.()
       ctx.removeFromQueue()
-      resolveOnce(ctx.cancelAndAbort(undefined, true))
+      resolveOnce(
+        ctx.cancelAndAbort(undefined, true, undefined, {
+          source: abortTrace.source ?? 'permission_abort',
+          causalEventId: abortTrace.causalEventId,
+        }),
+      )
     }
     if (abortSignal.aborted) {
       // Already aborted: cancel and stop setup so we never enqueue a stale prompt.
@@ -190,7 +205,7 @@ function handleInteractivePermission(
           ctx.removeFromQueue()
         }
       },
-      onAbort() {
+      onAbort(source, causalEventId) {
         if (!claim()) return
         if (bridgeCallbacks && bridgeRequestId) {
           bridgeCallbacks.sendResponse(bridgeRequestId, {
@@ -205,7 +220,12 @@ function handleInteractivePermission(
           { decision: 'reject', source: { type: 'user_abort' } },
           { permissionPromptStartTimeMs },
         )
-        resolveOnce(ctx.cancelAndAbort(undefined, true))
+        resolveOnce(
+          ctx.cancelAndAbort(undefined, true, undefined, {
+            source: source ?? 'permission_dialog',
+            causalEventId,
+          }),
+        )
       },
       async onAllow(
         updatedInput,

src/hooks/useBackgroundTaskNavigation.interruptionTrace.test.tsx

@@ -0,0 +1,223 @@
+import { PassThrough } from 'node:stream'
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import React, { useEffect } from 'react'
+import { createRoot } from '../ink.js'
+import { KeyboardEvent } from '../ink/events/keyboard-event.js'
+import { AppStateProvider, type AppState } from '../state/AppState.js'
+import { getDefaultAppState } from '../state/AppStateStore.js'
+import type { InProcessTeammateTaskState } from '../tasks/InProcessTeammateTask/types.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../utils/interruptionTrace.js'
+import { useBackgroundTaskNavigation } from './useBackgroundTaskNavigation.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock(
+    'hooks/useBackgroundTaskNavigation.interruptionTrace.test.tsx',
+  )
+})
+
+afterEach(() => {
+  try {
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+function Harness({
+  onReady,
+}: {
+  onReady: (handler: (event: KeyboardEvent) => void) => void
+}): React.ReactNode {
+  const { handleKeyDown } = useBackgroundTaskNavigation()
+  useEffect(() => onReady(handleKeyDown), [handleKeyDown, onReady])
+  return null
+}
+
+function createTeammateTask(): {
+  task: InProcessTeammateTaskState
+  currentWorkAbortController: AbortController
+  lifecycleAbortController: AbortController
+} {
+  const currentWorkAbortController = new AbortController()
+  const lifecycleAbortController = new AbortController()
+  return {
+    currentWorkAbortController,
+    lifecycleAbortController,
+    task: {
+      id: 'teammate-task-1',
+      type: 'in_process_teammate',
+      status: 'running',
+      description: 'test teammate',
+      startTime: Date.now(),
+      outputFile: '/tmp/test-teammate-output',
+      outputOffset: 0,
+      notified: false,
+      identity: {
+        agentId: 'researcher@test-team',
+        agentName: 'researcher',
+        teamName: '',
+        planModeRequired: false,
+        parentSessionId: 'parent-session',
+      },
+      prompt: 'test',
+      abortController: lifecycleAbortController,
+      currentWorkAbortController,
+      awaitingPlanApproval: false,
+      permissionMode: 'default',
+      isIdle: false,
+      shutdownRequested: false,
+      pendingUserMessages: [],
+      lastReportedToolCount: 0,
+      lastReportedTokenCount: 0,
+    },
+  }
+}
+
+async function renderNavigation(initialState: AppState): Promise<{
+  invoke: (key: 'escape' | 'k') => void
+  cleanup: () => Promise<void>
+}> {
+  const stdout = new PassThrough()
+  const stdin = new PassThrough() as PassThrough & {
+    isTTY: boolean
+    setRawMode: (mode: boolean) => void
+    ref: () => void
+    unref: () => void
+  }
+  stdin.isTTY = true
+  stdin.setRawMode = () => {}
+  stdin.ref = () => {}
+  stdin.unref = () => {}
+  ;(stdout as unknown as { columns: number }).columns = 120
+  const root = await createRoot({
+    stdout: stdout as unknown as NodeJS.WriteStream,
+    stdin: stdin as unknown as NodeJS.ReadStream,
+    patchConsole: false,
+  })
+  let handler: ((event: KeyboardEvent) => void) | undefined
+  try {
+    root.render(
+      <AppStateProvider initialState={initialState}>
+        <Harness
+          onReady={value => {
+            handler = value
+          }}
+        />
+      </AppStateProvider>,
+    )
+    for (let attempts = 0; attempts < 100 && !handler; attempts++) {
+      await Bun.sleep(10)
+    }
+    expect(handler).toBeDefined()
+    return {
+      invoke(key) {
+        handler!(
+          new KeyboardEvent({
+            kind: 'key',
+            name: key,
+            sequence: key === 'escape' ? '\u001b' : key,
+            raw: key === 'escape' ? '\u001b' : key,
+            ctrl: false,
+            shift: false,
+            meta: false,
+            option: false,
+            super: false,
+            fn: false,
+            isPasted: false,
+          }),
+        )
+      },
+      async cleanup() {
+        root.unmount()
+        await Bun.sleep(30)
+        stdin.end()
+        stdout.end()
+      },
+    }
+  } catch (error) {
+    root.unmount()
+    await Bun.sleep(30)
+    stdin.end()
+    stdout.end()
+    throw error
+  }
+}
+
+test('records Escape causality before aborting the current teammate turn', async () => {
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  const { task, currentWorkAbortController } = createTeammateTask()
+  const rendered = await renderNavigation({
+    ...getDefaultAppState(),
+    tasks: { [task.id]: task },
+    viewingAgentTaskId: task.id,
+    viewSelectionMode: 'viewing-agent',
+  })
+
+  try {
+    rendered.invoke('escape')
+    const entries = __getInterruptionTraceSnapshotForTests()
+    const input = entries.find(entry => entry.event === 'input.teammate_escape')
+    const requested = entries.find(entry => entry.event === 'abort.requested')
+    expect(currentWorkAbortController.signal.aborted).toBe(true)
+    expect(currentWorkAbortController.signal.reason).toBeInstanceOf(
+      DOMException,
+    )
+    expect(
+      (currentWorkAbortController.signal.reason as DOMException).name,
+    ).toBe('AbortError')
+    expect(input).toBeDefined()
+    expect(requested).toMatchObject({
+      source: 'teammate_escape',
+      subsystem: 'in_process_teammate',
+      controllerRole: 'subagent-turn',
+      subagentId: 'researcher@test-team',
+      causalEventId: input?.eventId,
+    })
+  } finally {
+    await rendered.cleanup()
+  }
+})
+
+test('records kill-key causality before aborting the teammate lifecycle', async () => {
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  const { task, lifecycleAbortController } = createTeammateTask()
+  const rendered = await renderNavigation({
+    ...getDefaultAppState(),
+    tasks: { [task.id]: task },
+    expandedView: 'teammates',
+    selectedIPAgentIndex: 0,
+    viewSelectionMode: 'selecting-agent',
+  })
+
+  try {
+    rendered.invoke('k')
+    const entries = __getInterruptionTraceSnapshotForTests()
+    const input = entries.find(entry => entry.event === 'input.teammate_kill')
+    const requested = entries.find(entry => entry.event === 'abort.requested')
+    expect(lifecycleAbortController.signal.aborted).toBe(true)
+    expect(input).toBeDefined()
+    expect(requested).toMatchObject({
+      source: 'teammate_kill',
+      subsystem: 'in_process_teammate',
+      controllerRole: 'subagent-lifecycle',
+      subagentId: 'researcher@test-team',
+      causalEventId: input?.eventId,
+    })
+  } finally {
+    await rendered.cleanup()
+  }
+})

src/hooks/useBackgroundTaskNavigation.ts

@@ -11,15 +11,17 @@ import {
   enterTeammateView,
   exitTeammateView,
 } from '../state/teammateViewHelpers.js'
-import {
+import { getRunningTeammatesSorted } from '../tasks/InProcessTeammateTask/InProcessTeammateTask.js'
-  getRunningTeammatesSorted,
-  InProcessTeammateTask,
-} from '../tasks/InProcessTeammateTask/InProcessTeammateTask.js'
 import {
   type InProcessTeammateTaskState,
   isInProcessTeammateTask,
 } from '../tasks/InProcessTeammateTask/types.js'
 import { isBackgroundTask } from '../tasks/types.js'
+import {
+  requestAbort,
+  traceInterruptionEvent,
+} from '../utils/interruptionTrace.js'
+import { killInProcessTeammate } from '../utils/swarm/spawnInProcess.js'
 
 // Step teammate selection by delta, wrapping across leader(-1)..teammates(0..n-1)..hide(n).
 // First step from a collapsed tree expands it and parks on leader.
@@ -155,7 +157,23 @@ export function useBackgroundTaskNavigation(options?: {
         const task = tasks[taskId]
         if (isInProcessTeammateTask(task) && task.status === 'running') {
           // Abort currentWorkAbortController (stops current turn) NOT abortController (kills teammate)
-          task.currentWorkAbortController?.abort()
+          const causalEventId = traceInterruptionEvent(
+            'input.teammate_escape',
+            {
+              source: 'teammate_escape',
+              subsystem: 'in_process_teammate',
+              subagentId: task.identity.agentId,
+            },
+          )
+          if (task.currentWorkAbortController) {
+            requestAbort(task.currentWorkAbortController, undefined, {
+              source: 'teammate_escape',
+              subsystem: 'in_process_teammate',
+              controllerRole: 'subagent-turn',
+              subagentId: task.identity.agentId,
+              causalEventId,
+            })
+          }
           return
         }
       }
@@ -233,7 +251,15 @@ export function useBackgroundTaskNavigation(options?: {
       e.preventDefault()
       const selected = getSelectedTeammate()
       if (selected && selected.task.status === 'running') {
-        void InProcessTeammateTask.kill(selected.taskId, setAppState)
+        const causalEventId = traceInterruptionEvent('input.teammate_kill', {
+          source: 'teammate_kill',
+          subsystem: 'in_process_teammate',
+          subagentId: selected.task.identity.agentId,
+        })
+        killInProcessTeammate(selected.taskId, setAppState, {
+          source: 'teammate_kill',
+          causalEventId,
+        })
       }
       return
     }

src/hooks/useCancelRequest.test.tsx

@@ -0,0 +1,304 @@
+import { PassThrough } from 'node:stream'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  mock,
+  spyOn,
+  test,
+} from 'bun:test'
+import React from 'react'
+import * as analytics from '../services/analytics/index.js'
+import { createRoot } from '../ink.js'
+import { KeybindingProvider } from '../keybindings/KeybindingContext.js'
+import type {
+  KeybindingContextName,
+  ParsedKeystroke,
+} from '../keybindings/types.js'
+import { AppStateProvider } from '../state/AppState.js'
+import {
+  getDefaultAppState,
+  type AppState,
+} from '../state/AppStateStore.js'
+import { CancelRequestHandler } from './useCancelRequest.js'
+import type { LocalAgentTaskState } from '../tasks/LocalAgentTask/LocalAgentTask.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../utils/interruptionTrace.js'
+
+type HandlerRegistration = {
+  action: string
+  context: KeybindingContextName
+  handler: () => void
+}
+
+function TestKeybindingProvider({
+  children,
+  registry,
+}: {
+  children: React.ReactNode
+  registry: React.RefObject<Map<string, Set<HandlerRegistration>>>
+}): React.ReactNode {
+  const pendingChordRef = React.useRef<ParsedKeystroke[] | null>(null)
+  const [pendingChord, setPendingChord] = React.useState<
+    ParsedKeystroke[] | null
+  >(null)
+  const [activeContexts] = React.useState(
+    () => new Set<KeybindingContextName>(['Chat', 'Global']),
+  )
+  return (
+    <KeybindingProvider
+      bindings={[]}
+      pendingChordRef={pendingChordRef}
+      pendingChord={pendingChord}
+      setPendingChord={setPendingChord}
+      activeContexts={activeContexts}
+      registerActiveContext={context => activeContexts.add(context)}
+      unregisterActiveContext={context => activeContexts.delete(context)}
+      handlerRegistryRef={registry}
+    >
+      {children}
+    </KeybindingProvider>
+  )
+}
+
+function createTestStreams() {
+  const stdout = new PassThrough()
+  const stdin = new PassThrough() as PassThrough & {
+    isTTY: boolean
+    setRawMode: (mode: boolean) => void
+    ref: () => void
+    unref: () => void
+  }
+  stdin.isTTY = true
+  stdin.setRawMode = () => {}
+  stdin.ref = () => {}
+  stdin.unref = () => {}
+  ;(stdout as unknown as { columns: number }).columns = 120
+  return { stdout, stdin }
+}
+
+async function waitFor(
+  predicate: () => boolean,
+  label: string,
+  timeoutMs = 2_000,
+): Promise<void> {
+  const startedAt = Date.now()
+  while (Date.now() - startedAt < timeoutMs) {
+    if (predicate()) return
+    await Bun.sleep(10)
+  }
+  throw new Error(`Timed out waiting for ${label}`)
+}
+
+async function renderCancelHandler(
+  initialState: AppState,
+  options: { failAfterRender?: boolean; onCleanup?: () => void } = {},
+) {
+  const { stdout, stdin } = createTestStreams()
+  const root = await createRoot({
+    stdout: stdout as unknown as NodeJS.WriteStream,
+    stdin: stdin as unknown as NodeJS.ReadStream,
+    patchConsole: false,
+  })
+  const registry = {
+    current: new Map<string, Set<HandlerRegistration>>(),
+  }
+  const onCancel = mock((_source: string, _causalEventId?: string) => {})
+  let latestState = initialState
+  const cleanup = async () => {
+    root.unmount()
+    await Bun.sleep(30)
+    stdin.end()
+    stdout.end()
+    options.onCleanup?.()
+  }
+  try {
+    root.render(
+      <AppStateProvider
+        initialState={initialState}
+        onChangeAppState={({ newState }) => {
+          latestState = newState
+        }}
+      >
+        <TestKeybindingProvider registry={registry}>
+          <CancelRequestHandler
+            setToolUseConfirmQueue={() => {}}
+            onCancel={onCancel}
+            onAgentsKilled={() => {}}
+            isMessageSelectorVisible={false}
+            screen="prompt"
+            abortSignal={new AbortController().signal}
+          />
+        </TestKeybindingProvider>
+      </AppStateProvider>,
+    )
+    if (options.failAfterRender) throw new Error('synthetic setup failure')
+    await waitFor(
+      () =>
+        registry.current.has('app:interrupt') &&
+        (initialState.viewSelectionMode === 'viewing-agent' ||
+          registry.current.has('chat:cancel')),
+      'cancel keybinding registration',
+    )
+  } catch (error) {
+    await cleanup()
+    throw error
+  }
+  return {
+    onCancel,
+    invoke(action: 'chat:cancel' | 'app:interrupt') {
+      const registration = registry.current.get(action)?.values().next().value
+      if (!registration) throw new Error(`Missing ${action} handler`)
+      registration.handler()
+    },
+    getState: () => latestState,
+    cleanup,
+  }
+}
+
+const originalInterruptionTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+let hasSharedMutationLock = false
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('hooks/useCancelRequest.test.tsx')
+  hasSharedMutationLock = true
+})
+
+afterEach(async () => {
+  try {
+    mock.restore()
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalInterruptionTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalInterruptionTrace
+    }
+  } finally {
+    if (hasSharedMutationLock) {
+      releaseSharedMutationLock()
+      hasSharedMutationLock = false
+    }
+  }
+})
+
+describe('CancelRequestHandler interruption sources', () => {
+  test('cleans up the Ink root and streams when setup fails', async () => {
+    let cleanupCount = 0
+
+    await expect(
+      renderCancelHandler(getDefaultAppState(), {
+        failAfterRender: true,
+        onCleanup: () => {
+          cleanupCount++
+        },
+      }),
+    ).rejects.toThrow('synthetic setup failure')
+    expect(cleanupCount).toBe(1)
+  })
+
+  test('chat:cancel preserves escape analytics and passes the precise cancel source', async () => {
+    const logEvent = spyOn(analytics, 'logEvent').mockImplementation(() => {})
+    const rendered = await renderCancelHandler(getDefaultAppState())
+    try {
+      rendered.invoke('chat:cancel')
+
+      expect(rendered.onCancel).toHaveBeenCalledWith(
+        'cancel_keybinding',
+        undefined,
+      )
+      expect(logEvent).toHaveBeenCalledWith(
+        'tengu_cancel',
+        expect.objectContaining({ source: 'escape' }),
+      )
+    } finally {
+      await rendered.cleanup()
+    }
+  })
+
+  test('app:interrupt preserves escape analytics while passing ctrl_c', async () => {
+    const logEvent = spyOn(analytics, 'logEvent').mockImplementation(() => {})
+    const rendered = await renderCancelHandler({
+      ...getDefaultAppState(),
+      viewSelectionMode: 'viewing-agent',
+    })
+    try {
+      rendered.invoke('app:interrupt')
+
+      expect(rendered.onCancel).toHaveBeenCalledWith('ctrl_c', undefined)
+      expect(rendered.getState().viewSelectionMode).toBe('none')
+      expect(logEvent).toHaveBeenCalledWith(
+        'tengu_cancel',
+        expect.objectContaining({ source: 'escape' }),
+      )
+    } finally {
+      await rendered.cleanup()
+    }
+  })
+
+  test('app:interrupt links background-agent aborts to the Ctrl-C input', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const agentAbortController = new AbortController()
+    const agentTask: LocalAgentTaskState = {
+      id: 'agent-1',
+      type: 'local_agent',
+      status: 'running',
+      description: 'trace test agent',
+      startTime: Date.now(),
+      outputFile: join(tmpdir(), 'openclaude-trace-test-agent.output'),
+      outputOffset: 0,
+      notified: false,
+      agentId: 'agent-1',
+      prompt: 'test',
+      agentType: 'general-purpose',
+      abortController: agentAbortController,
+      retrieved: false,
+      lastReportedToolCount: 0,
+      lastReportedTokenCount: 0,
+      isBackgrounded: true,
+      pendingMessages: [],
+      retain: false,
+      diskLoaded: false,
+    }
+    const rendered = await renderCancelHandler({
+      ...getDefaultAppState(),
+      viewSelectionMode: 'viewing-agent',
+      viewingAgentTaskId: 'agent-1',
+      tasks: { 'agent-1': agentTask },
+    })
+    try {
+      rendered.invoke('app:interrupt')
+      await waitFor(
+        () => agentAbortController.signal.aborted,
+        'background-agent abort',
+      )
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const input = trace.find(entry => entry.event === 'input.ctrl_c')
+      const agentAbort = trace.find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.controllerRole === 'background-agent',
+      )
+      expect(input).toBeDefined()
+      expect(agentAbort).toMatchObject({
+        source: 'ctrl_c',
+        subagentId: 'agent-1',
+        causalEventId: input!.eventId,
+      })
+    } finally {
+      await rendered.cleanup()
+    }
+  })
+})

src/hooks/useCancelRequest.ts

@@ -33,15 +33,18 @@ import {
   hasCommandsInQueue,
 } from '../utils/messageQueueManager.js'
 import { emitTaskTerminatedSdk } from '../utils/sdkEventQueue.js'
+import { traceInterruptionEvent } from '../utils/interruptionTrace.js'
 
 /** Time window in ms during which a second press kills all background agents. */
 const KILL_AGENTS_CONFIRM_WINDOW_MS = 3000
 
+export type CancelRequestSource = 'cancel_keybinding' | 'ctrl_c'
+
 type CancelRequestHandlerProps = {
   setToolUseConfirmQueue: (
     f: (toolUseConfirmQueue: ToolUseConfirm[]) => ToolUseConfirm[],
   ) => void
-  onCancel: () => void
+  onCancel: (source: CancelRequestSource, causalEventId?: string) => void
   onAgentsKilled: () => void
   isMessageSelectorVisible: boolean
   screen: Screen
@@ -84,7 +87,10 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
   const lastKillAgentsPressRef = useRef<number>(0)
   const viewSelectionMode = useAppState(s => s.viewSelectionMode)
 
-  const handleCancel = useCallback(() => {
+  const handleCancel = useCallback((
+    source: CancelRequestSource,
+    causalEventId?: string,
+  ) => {
     const cancelProps = {
       source:
         'escape' as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
@@ -97,7 +103,7 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
     if (abortSignal !== undefined && !abortSignal.aborted) {
       logEvent('tengu_cancel', cancelProps)
       setToolUseConfirmQueue(() => [])
-      onCancel()
+      onCancel(source, causalEventId)
       return
     }
 
@@ -112,7 +118,7 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
     // Fallback: nothing to cancel or pop (shouldn't reach here if isActive is correct)
     logEvent('tengu_cancel', cancelProps)
     setToolUseConfirmQueue(() => [])
-    onCancel()
+    onCancel(source, causalEventId)
   }, [
     abortSignal,
     popCommandFromQueue,
@@ -161,7 +167,18 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
     isContextActive &&
     (canCancelRunningTask || hasQueuedCommands || isViewingTeammate)
 
-  useKeybinding('chat:cancel', handleCancel, {
+  const handleCancelKeybinding = useCallback(
+    () => {
+      const causalEventId = traceInterruptionEvent('input.cancel_keybinding', {
+        source: 'cancel_keybinding',
+        subsystem: 'cancel_request',
+      })
+      handleCancel('cancel_keybinding', causalEventId)
+    },
+    [handleCancel],
+  )
+
+  useKeybinding('chat:cancel', handleCancelKeybinding, {
     context: 'Chat',
     isActive: isEscapeActive,
   })
@@ -169,13 +186,14 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
   // Shared kill path: stop all agents, suppress per-agent notifications,
   // emit SDK events, enqueue a single aggregate model-facing notification.
   // Returns true if anything was killed.
-  const killAllAgentsAndNotify = useCallback((): boolean => {
+  const killAllAgentsAndNotify = useCallback(
+    (source: string, causalEventId?: string): boolean => {
     const tasks = store.getState().tasks
     const running = Object.entries(tasks).filter(
       ([, t]) => t.type === 'local_agent' && t.status === 'running',
     )
     if (running.length === 0) return false
-    killAllRunningAgentTasks(tasks, setAppState)
+    killAllRunningAgentTasks(tasks, setAppState, { source, causalEventId })
     const descriptions: string[] = []
     for (const [taskId, task] of running) {
       markAgentsNotified(taskId, setAppState)
@@ -192,18 +210,25 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
     enqueuePendingNotification({ value: summary, mode: 'task-notification' })
     onAgentsKilled()
       return true
-  }, [store, setAppState, onAgentsKilled])
+    },
+    [store, setAppState, onAgentsKilled],
+  )
 
   // Ctrl+C (app:interrupt). Scoped to teammate-view: killing agents from the
   // main prompt stays a deliberate gesture (chat:killAgents), not a
   // side-effect of cancelling a turn.
   const handleInterrupt = useCallback(() => {
+    const causalEventId = traceInterruptionEvent('input.ctrl_c', {
+      source: 'ctrl_c',
+      subsystem: 'cancel_request',
+      phase: isViewingTeammate ? 'teammate_view' : 'main_view',
+    })
     if (isViewingTeammate) {
-      killAllAgentsAndNotify()
+      killAllAgentsAndNotify('ctrl_c', causalEventId)
       exitTeammateView(setAppState)
     }
     if (canCancelRunningTask || hasQueuedCommands) {
-      handleCancel()
+      handleCancel('ctrl_c', causalEventId)
     }
   }, [
     isViewingTeammate,
@@ -247,7 +272,11 @@ export function CancelRequestHandler(props: CancelRequestHandlerProps): null {
           'kill_agents' as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
       })
       clearCommandQueue()
-      killAllAgentsAndNotify()
+      const causalEventId = traceInterruptionEvent('input.kill_agents', {
+        source: 'kill_agents',
+        subsystem: 'cancel_request',
+      })
+      killAllAgentsAndNotify('kill_agents', causalEventId)
       return
     }
     // First press -- show confirmation hint in status bar

src/hooks/useInboxPoller.ts

@@ -21,6 +21,7 @@ import {
   handlePlanApprovalResponse,
 } from '../utils/inProcessTeammateHelpers.js'
 import { createAssistantMessage } from '../utils/messages.js'
+import { tracePermissionAbortResolution } from '../utils/interruptionTrace.js'
 import { requestPermissionModeChange } from '../utils/permissions/permissionModeChange.js'
 import {
   applyPermissionModeChange,
@@ -313,7 +314,12 @@ export function useInboxPoller({
             onUserInteraction() {
               // No-op for tmux workers (no classifier auto-approval)
             },
-            onAbort() {
+            onAbort(source, causalEventId) {
+              tracePermissionAbortResolution(
+                source,
+                causalEventId,
+                'tmux_permission_bridge',
+              )
               void sendPermissionResponseViaMailbox(
                 parsed.agent_id,
                 { decision: 'rejected', resolvedBy: 'leader' },

src/hooks/useReplBridge.tsx

@@ -20,6 +20,7 @@ import type { Message } from '../types/message.js';
 import { getCwd } from '../utils/cwd.js';
 import { logForDebugging } from '../utils/debug.js';
 import { errorMessage } from '../utils/errors.js';
+import { requestBridgeInterrupt } from '../utils/replInterruption.js';
 import { enqueue } from '../utils/messageQueueManager.js';
 import { buildSystemInitMessage } from '../utils/messages/systemInit.js';
 import { createBridgeStatusMessage, createSystemMessage } from '../utils/messages.js';
@@ -393,7 +394,7 @@ export function useReplBridge(messages: Message[], setMessages: (action: React.S
             onInboundMessage: handleInboundMessage,
             onPermissionResponse: handlePermissionResponse,
             onInterrupt() {
-              abortControllerRef.current?.abort('interrupt');
+              requestBridgeInterrupt(abortControllerRef);
             },
             onSetModel(model) {
               const resolved = model === 'default' ? null : model ?? null;

src/hooks/useSSHSession.ts

@@ -28,6 +28,7 @@ import type { Message as MessageType } from '../types/message.js'
 import type { PermissionAskDecision } from '../types/permissions.js'
 import { logForDebugging } from '../utils/debug.js'
 import { gracefulShutdown } from '../utils/gracefulShutdown.js'
+import { tracePermissionAbortResolution } from '../utils/interruptionTrace.js'
 import type { RemoteMessageContent } from '../utils/teleport/api.js'
 
 type UseSSHSessionResult = {
@@ -121,7 +122,12 @@ export function useSSHSession({
           permissionResult,
           permissionPromptStartTimeMs: Date.now(),
           onUserInteraction() {},
-          onAbort() {
+          onAbort(source, causalEventId) {
+            tracePermissionAbortResolution(
+              source,
+              causalEventId,
+              'ssh_permission_bridge',
+            )
             manager.respondToPermissionRequest(requestId, {
               behavior: 'deny',
               message: 'User aborted',

src/query.abortClassification.test.ts

@@ -11,6 +11,16 @@ import {
   INTERRUPT_MESSAGE,
 } from './utils/messages.js'
 import { asSystemPrompt } from './utils/systemPromptType.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  requestAbort,
+} from './utils/interruptionTrace.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from './test/sharedMutationLock.js'
 
 const DEFAULT_ABORT = Symbol('default abort')
 
@@ -55,11 +65,10 @@ function makeToolUseContext(tools: Tools = []): QueryParams['toolUseContext'] {
 }
 
 function abort(controller: AbortController, reason: AbortInput): void {
-  if (reason === DEFAULT_ABORT) {
+  requestAbort(controller, reason === DEFAULT_ABORT ? undefined : reason, {
-    controller.abort()
+    source: 'query_abort_test',
-    return
+    controllerRole: 'query-root',
-  }
+  })
-  controller.abort(reason)
 }
 
 function makeBaseParams(
@@ -170,6 +179,33 @@ function interruptionMessages(yielded: any[]) {
 }
 
 describe('query abort classification', () => {
+  test.serial('links abort classification to the winning root abort', async () => {
+    await acquireSharedMutationLock('query abort classification trace')
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    try {
+      await drainWithReturn(makeParams('query-timeout'))
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const rootAbort = trace.find(entry => entry.event === 'abort.requested')
+      const classified = trace.find(
+        entry => entry.event === 'query.abort_classified',
+      )
+      expect(rootAbort).toBeDefined()
+      expect(classified).toBeDefined()
+      expect(typeof rootAbort!.eventId).toBe('string')
+      expect(typeof classified!.causalEventId).toBe('string')
+      expect(classified!.causalEventId).toBe(rootAbort!.eventId)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      releaseSharedMutationLock()
+    }
+  })
+
   test('query timeout aborts produce timeout transcript text without user interruption', async () => {
     const { yielded, returned } = await drainWithReturn(
       makeParams('query-timeout'),

src/query.ts

@@ -5,6 +5,7 @@ import type {
 } from '@anthropic-ai/sdk/resources/index.mjs'
 import type { CanUseToolFn } from './hooks/useCanUseTool.js'
 import { FallbackTriggeredError } from './services/api/withRetry.js'
+import { isMainThreadGoalSource } from './services/goal/controller.js'
 import {
   calculateTokenWarningState,
   getAutoCompactThreshold,
@@ -55,6 +56,11 @@ import {
   normalizeAbortReason,
   shouldCreateUserInterruptionMessage,
 } from './utils/abortReasons.js'
+import {
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  traceInterruptionEvent,
+} from './utils/interruptionTrace.js'
 import {
   createAssistantMessage,
   createUserMessage,
@@ -185,6 +191,27 @@ async function cleanupComputerUseAtTerminal(
   }
 }
 
+function traceAbortMessageSelection(
+  signal: AbortSignal,
+  phase: 'streaming' | 'tools' | 'post-tools',
+): void {
+  const abortReason = signal.reason
+  const createsUserInterruption = shouldCreateUserInterruptionMessage(abortReason)
+  const createsSystemWarning = getQueryAbortSystemMessage(abortReason) !== null
+  traceInterruptionEvent('query.abort_classified', {
+    subsystem: 'query',
+    phase,
+    reason: abortReason,
+    causalEventId: getInterruptionSignalAbortEventId(signal),
+    outcome: createsUserInterruption
+      ? 'user_interruption'
+      : createsSystemWarning
+        ? 'system_warning'
+        : 'silent',
+  })
+  flushInterruptionTrace('query_abort_classified')
+}
+
 async function* emitAbortedStreaming(
   signal: AbortSignal,
   toolUseContext: ToolUseContext,
@@ -194,6 +221,7 @@ async function* emitAbortedStreaming(
 > {
   await cleanupComputerUseAtTerminal(toolUseContext)
   const abortReason = signal.reason
+  traceAbortMessageSelection(signal, 'streaming')
   const abortSystemMessage = getQueryAbortSystemMessage(abortReason)
   if (abortSystemMessage) {
     yield createSystemMessage(abortSystemMessage, 'warning')
@@ -211,6 +239,7 @@ function* emitAbortedToolsAfterCleanup(
   hasSharedTurnBudget: boolean,
 ): Generator<Message, Extract<Terminal, { reason: 'aborted_tools' }>> {
   const abortReason = signal.reason
+  traceAbortMessageSelection(signal, 'tools')
   const abortSystemMessage = getQueryAbortSystemMessage(abortReason)
   if (abortSystemMessage) {
     yield createSystemMessage(abortSystemMessage, 'warning')
@@ -794,6 +823,19 @@ async function* queryLoop(
     state.toolUseContext,
   )
 
+  const activeGoal = state.toolUseContext.getAppState().goal
+  if (
+    activeGoal?.status === 'active' &&
+    isMainThreadGoalSource(querySource, state.toolUseContext)
+  ) {
+    traceInterruptionEvent('goal.main_turn_started', {
+      subsystem: 'goal',
+      phase: 'main_query',
+      querySource,
+      attemptId: activeGoal.id,
+    })
+  }
+
   // eslint-disable-next-line no-constant-condition
   while (true) {
     // Destructure state at the top of each iteration. toolUseContext alone
@@ -2007,6 +2049,7 @@ async function* queryLoop(
     // Without this, tool_use blocks would lack matching tool_result blocks.
     if (toolUseContext.abortController.signal.aborted) {
       const abortReason = toolUseContext.abortController.signal.reason
+      traceAbortMessageSelection(toolUseContext.abortController.signal, 'post-tools')
       if (streamingToolExecutor) {
         // Consume remaining results - executor generates synthetic tool_results for
         // aborted tools since it checks the abort signal in executeTool()

src/remote/remotePermissionBridge.ts

@@ -5,6 +5,7 @@ import type { AssistantMessage } from '../types/message.js'
 import type { PermissionAskDecision } from '../types/permissions.js'
 import { jsonStringify } from '../utils/slowOperations.js'
 import type { ToolUseConfirm } from '../components/permissions/PermissionRequest.js'
+import { tracePermissionAbortResolution } from '../utils/interruptionTrace.js'
 
 /**
  * Create a synthetic AssistantMessage for remote permission requests.
@@ -123,7 +124,12 @@ export function createRemotePermissionQueueItem({
     onUserInteraction() {
       // No-op for remote permission prompts.
     },
-    onAbort() {
+    onAbort(source, causalEventId) {
+      tracePermissionAbortResolution(
+        source,
+        causalEventId,
+        'remote_permission_bridge',
+      )
       respond({
         behavior: 'deny',
         message: 'User aborted',

src/screens/REPL.tsx

@@ -38,7 +38,7 @@ import { asSessionId, asAgentId } from '../types/ids.js';
 import { logForDebugging } from '../utils/debug.js';
 import { QueryGuard } from '../utils/QueryGuard.js';
 import { getQueryGuardOptionsFromEnv } from '../utils/queryGuardConfig.js';
-import { QueryLifecycleOperationTracker, formatQueryLifecycleAbortSignalReason, formatQueryLifecycleLogMessage, getQueryTerminalReason, type QueryActiveOperationSnapshot, type QueryGuardTimeoutInfo, type QueryLifecycleContext, type QueryTerminalReason } from '../utils/queryLifecycle.js';
+import { QueryLifecycleOperationTracker, formatQueryLifecycleAbortSignalReason, formatQueryLifecycleLogMessage, getQueryTerminalOutcome, getQueryTerminalReason, type QueryActiveOperationSnapshot, type QueryGuardTimeoutInfo, type QueryLifecycleContext, type QueryTerminalReason } from '../utils/queryLifecycle.js';
 import { claimBackgroundTurnBudget, canRestoreDeferredMaxTurnsCap, computeDeferredMaxTurnsCapForBackgroundHandoff, createForegroundTurnBudgetHandoff, getReplMaxTurnsWarning, releaseForegroundTurnBudget, resolveReplMaxTurnsForSession, shouldShowReplMaxTurnsUnlimitedWarning, shouldContinueBackgroundAfterForegroundQuery, waitForForegroundTurnBudgetSettlement, type ForegroundTurnBudgetHandoff } from './replMaxTurns.js';
 import { createCombinedAbortSignal } from '../utils/combinedAbortSignal.js';
 import { isEnvTruthy } from '../utils/envUtils.js';
@@ -92,7 +92,10 @@ import { CommandKeybindingHandlers } from '../hooks/useCommandKeybindings.js';
 import { KeybindingSetup } from '../keybindings/KeybindingProviderSetup.js';
 import { useShortcutDisplay } from '../keybindings/useShortcutDisplay.js';
 import { getShortcutDisplay } from '../keybindings/shortcutFormat.js';
-import { CancelRequestHandler } from '../hooks/useCancelRequest.js';
+import {
+  CancelRequestHandler,
+  type CancelRequestSource,
+} from '../hooks/useCancelRequest.js';
 import { useBackgroundTaskNavigation } from '../hooks/useBackgroundTaskNavigation.js';
 import { useSwarmInitialization } from '../hooks/useSwarmInitialization.js';
 import { useTeammateViewAutoExit } from '../hooks/useTeammateViewAutoExit.js';
@@ -224,6 +227,18 @@ import { RemoteCallout } from '../components/RemoteCallout.js';
 import { getAPIProvider } from '../utils/model/providers.js';
 import { activityManager } from '../utils/activityManager.js';
 import { createAbortController } from '../utils/abortController.js';
+import {
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  registerInterruptionController,
+  requestAbort,
+  traceInterruptionEvent,
+} from '../utils/interruptionTrace.js';
+import { driveQueryEvents } from '../utils/queryEventDriver.js';
+import {
+  requestBackgroundHandoffAbort,
+  requestPriorityNowAbort,
+} from '../utils/replInterruption.js';
 import { MCPConnectionManager } from 'src/services/mcp/MCPConnectionManager.js';
 import { useFeedbackSurvey } from 'src/components/FeedbackSurvey/useFeedbackSurvey.js';
 import { useMemorySurvey } from 'src/components/FeedbackSurvey/useMemorySurvey.js';
@@ -1887,7 +1902,20 @@ export function REPL({
     const activeAbortController = abortControllerRef.current;
     if (activeAbortController && !activeAbortController.signal.aborted) {
       logQueryLifecycle('abort_requested', timeout.context, formatQueryLifecycleAbortSignalReason(timeoutAbortReason));
-      activeAbortController.abort(timeoutAbortReason);
+      requestAbort(activeAbortController, timeoutAbortReason, {
+        source: 'query_guard',
+        causalEventId: timeout.causalEventId,
+        subsystem: 'repl',
+        phase: 'timeout',
+        queryId: timeout.context.queryId,
+        queryGeneration: timeout.generation,
+        querySource: timeout.context.querySource,
+        controllerRole: 'query-root',
+        elapsedQueryMs: timeout.elapsedMs,
+        activeApiCallCount: timeout.activeOperations.apiCalls.length,
+        activeToolUseCount: timeout.activeOperations.toolUses.length,
+      });
+      flushInterruptionTrace('query_guard_timeout');
     }
     if (timeout.activeOperations.apiCalls.length > 0) {
       logForDebugging(`api.call.active_on_abort queryId=${timeout.context.queryId} generation=${timeout.generation} ${timeoutOperations}`);
@@ -2382,7 +2410,11 @@ export function REPL({
   }, [focusedInputDialog, repinScroll]);
   // Omitted means a programmatic edit/restore cancellation, which must not arm
   // correction context because those flows rewind the conversation themselves.
-  function onCancel(isUserInitiated = false) {
+  function onCancel(
+    isUserInitiated = false,
+    cancelSource: CancelRequestSource | 'programmatic' = 'programmatic',
+    causalEventId?: string,
+  ) {
     if (focusedInputDialog === 'elicitation') {
       // Elicitation dialog handles its own Escape, and closing it shouldn't affect any loading state.
       return;
@@ -2436,7 +2468,7 @@ export function REPL({
     }
     if (focusedInputDialog === 'tool-permission') {
       // Tool use confirm handles the abort signal itself
-      toolUseConfirmQueue[0]?.onAbort();
+      toolUseConfirmQueue[0]?.onAbort(cancelSource, causalEventId);
       setToolUseConfirmQueue([]);
     } else if (focusedInputDialog === 'prompt') {
       // Reject all pending prompts and clear the queue
@@ -2444,12 +2476,26 @@ export function REPL({
         item.reject(new Error('Prompt cancelled by user'));
       }
       setPromptQueue([]);
-      abortController?.abort('user-cancel');
+      if (abortController) {
+        requestAbort(abortController, 'user-cancel', {
+          source: cancelSource,
+          causalEventId,
+          subsystem: 'repl',
+          controllerRole: 'query-root',
+        });
+      }
     } else if (activeRemote.isRemoteMode) {
       // Remote mode: send interrupt signal to CCR
       activeRemote.cancelRequest();
     } else {
-      abortController?.abort('user-cancel');
+      if (abortController) {
+        requestAbort(abortController, 'user-cancel', {
+          source: cancelSource,
+          causalEventId,
+          subsystem: 'repl',
+          controllerRole: 'query-root',
+        });
+      }
     }
     if (cancelContext) {
       logQueryLifecycle('abort_acknowledged', cancelContext, formatQueryLifecycleAbortSignalReason('user-cancel'));
@@ -2496,7 +2542,7 @@ export function REPL({
   // CancelRequestHandler props - rendered inside KeybindingSetup
   const cancelRequestProps = {
     setToolUseConfirmQueue,
-    onCancel: () => onCancel(true),
+    onCancel: (source, causalEventId) => onCancel(true, source, causalEventId),
     onAgentsKilled: () => setMessages(prev => [...prev, createAgentsKilledMessage()]),
     isMessageSelectorVisible: isMessageSelectorVisible || !!showBashesDialog,
     screen,
@@ -3018,7 +3064,7 @@ export function REPL({
     // but its controller must be reachable during preparation so Escape can
     // cancel the handoff before it dispatches a provider request.
     setAbortController(backgroundSession.abortController);
-    abortController?.abort('background');
+    requestBackgroundHandoffAbort(abortController);
   }, [abortController, mainLoopModel, toolPermissionContext, mainThreadAgentDefinition, getToolUseContext, customSystemPrompt, appendSystemPrompt, canUseTool, setAppState, getAutoCompactTrackingForSession, setAutoCompactTrackingForSession, fallbackModel, setAbortController, addNotification, terminalTitle]);
   const {
     handleBackgroundSession
@@ -3266,23 +3312,11 @@ export function REPL({
         }
       }
     });
-    let queryTerminal: QueryTerminal;
+    const queryTerminal = await driveQueryEvents(
-    let generatorDone = false;
+      queryGenerator,
-    try {
+      reason => queryGuard.registerActivity(reason, queryGeneration),
-      while (true) {
+      onQueryEvent,
-        const next = await queryGenerator.next();
+    );
-        if (next.done) {
-          generatorDone = true;
-          queryTerminal = next.value;
-          break;
-        }
-        const event = next.value;
-        queryGuard.registerActivity(`query_event:${event.type}`, queryGeneration);
-        onQueryEvent(event);
-      }
-    } finally {
-      if (!generatorDone) await queryGenerator.return(undefined as never);
-    }
     if (isBuddyEnabled()) {
       void fireCompanionObserver(messagesRef.current, reaction => setAppState(prev => prev.companionReaction === reaction ? prev : {
         ...prev,
@@ -3359,6 +3393,20 @@ export function REPL({
     const turnBudget = turnBudgetHandoff.budget;
     foregroundTurnBudgetRef.current = turnBudgetHandoff;
     const queryContext = startResult.context;
+    registerInterruptionController(abortController, {
+      subsystem: 'repl',
+      controllerRole: 'query-root',
+      queryId: queryContext.queryId,
+      queryGeneration: thisGeneration,
+      querySource: queryContext.querySource,
+    });
+    traceInterruptionEvent('query.started', {
+      subsystem: 'repl',
+      phase: 'running',
+      queryId: queryContext.queryId,
+      queryGeneration: thisGeneration,
+      querySource: queryContext.querySource,
+    });
     logQueryLifecycle('start', queryContext);
     logQueryLifecycle('guard_start', queryContext);
     let didThrow = false;
@@ -3456,8 +3504,24 @@ export function REPL({
       // then clear it only when this query reaches its terminal cleanup.
       interruptionCorrectionTracker.finishModelTurn(queryContext.queryId);
       const terminalReason = getQueryTerminalReason(abortController.signal, didThrow);
+      const terminalOutcome = getQueryTerminalOutcome(abortController.signal, didThrow);
       const abortReason = getAbortReasonLabel(abortController.signal.reason);
       const activeOperations = lifecycleTracker.snapshot();
+      traceInterruptionEvent('query.terminal', {
+        subsystem: 'repl',
+        phase: terminalReason,
+        outcome: terminalOutcome,
+        queryId: queryContext.queryId,
+        queryGeneration: thisGeneration,
+        querySource: queryContext.querySource,
+        reason: abortController.signal.reason,
+        causalEventId: getInterruptionSignalAbortEventId(
+          abortController.signal,
+        ),
+        activeApiCallCount: activeOperations.apiCalls.length,
+        activeToolUseCount: activeOperations.toolUses.length,
+      });
+      if (abortController.signal.aborted) flushInterruptionTrace('query_terminal');
       const completedContext = {
         ...queryContext,
         terminalReason,
@@ -4660,7 +4724,7 @@ export function REPL({
   // (e.g. from a chat UI client via UDS).
   useEffect(() => {
     if (queuedCommands.some(cmd => cmd.priority === 'now')) {
-      abortControllerRef.current?.abort('interrupt');
+      requestPriorityNowAbort(abortControllerRef);
     }
   }, [queuedCommands]);
 

src/services/PromptSuggestion/speculation.test.ts

@@ -3,6 +3,10 @@ import type { AppState } from '../../state/AppStateStore.js'
 import { IDLE_SPECULATION_STATE } from '../../state/AppStateStore.js'
 import type { ToolUseContext } from '../../Tool.js'
 import type { REPLHookContext } from '../../utils/hooks/postSamplingHooks.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../../utils/interruptionTrace.js'
 import {
   acquireSharedMutationLock,
   releaseSharedMutationLock,
@@ -59,6 +63,9 @@ afterAll(() => {
 
 describe('startSpeculation', () => {
   test('stops speculative writes in plan mode even when bypass is available', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
     let appState = {
       speculation: IDLE_SPECULATION_STATE,
       toolPermissionContext: {
@@ -103,8 +110,35 @@ describe('startSpeculation', () => {
           toolName: 'Write',
         },
       })
+      expect(
+        __getInterruptionTraceSnapshotForTests().find(
+          entry => entry.event === 'abort.requested',
+        ),
+      ).toMatchObject({
+        source: 'speculation_edit_boundary',
+        subsystem: 'prompt_suggestion',
+        controllerRole: 'speculation',
+      })
+      abortSpeculation(setAppState)
+      expect(
+        __getInterruptionTraceSnapshotForTests().find(
+          entry => entry.event === 'abort.repeated',
+        ),
+      ).toMatchObject({
+        source: 'speculation_cancelled',
+        subsystem: 'prompt_suggestion',
+        controllerRole: 'speculation',
+        outcome: 'ignored_first_abort_wins',
+        repeatedCount: 1,
+      })
     } finally {
       abortSpeculation(setAppState)
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
     }
   })
 })

src/services/PromptSuggestion/speculation.ts

@@ -36,6 +36,7 @@ import {
 import { formatDuration, formatNumber } from '../../utils/format.js'
 import type { REPLHookContext } from '../../utils/hooks/postSamplingHooks.js'
 import { logError } from '../../utils/log.js'
+import { requestAbort } from '../../utils/interruptionTrace.js'
 import type { SetAppState } from '../../utils/messageQueueManager.js'
 import {
   createSystemMessage,
@@ -61,6 +62,17 @@ import {
 const MAX_SPECULATION_TURNS = 20
 const MAX_SPECULATION_MESSAGES = 100
 
+function requestSpeculationAbort(
+  controller: AbortController,
+  source: string,
+): void {
+  requestAbort(controller, undefined, {
+    source,
+    subsystem: 'prompt_suggestion',
+    controllerRole: 'speculation',
+  })
+}
+
 const WRITE_TOOLS = new Set(['Edit', 'Write', 'NotebookEdit'])
 const SAFE_READ_ONLY_TOOLS = new Set([
   'Read',
@@ -371,6 +383,11 @@ async function generatePipelinedSuggestion(
 
     const pipelineAbortController = createChildAbortController(
       parentAbortController,
+      undefined,
+      {
+        subsystem: 'prompt_suggestion',
+        controllerRole: 'suggestion-pipeline',
+      },
     )
     if (pipelineAbortController.signal.aborted) return
 
@@ -418,6 +435,11 @@ export async function startSpeculation(
 
   const abortController = createChildAbortController(
     context.toolUseContext.abortController,
+    undefined,
+    {
+      subsystem: 'prompt_suggestion',
+      controllerRole: 'speculation',
+    },
   )
 
   if (abortController.signal.aborted) return
@@ -442,7 +464,7 @@ export async function startSpeculation(
     speculation: {
       status: 'active',
       id,
-      abort: () => abortController.abort(),
+      abort: () => requestSpeculationAbort(abortController, 'speculation_cancelled'),
       startTime,
       messagesRef,
       writtenPathsRef,
@@ -495,7 +517,10 @@ export async function startSpeculation(
                 completedAt: Date.now(),
               },
             }))
-            abortController.abort()
+            requestSpeculationAbort(
+              abortController,
+              'speculation_edit_boundary',
+            )
             return denySpeculation(
               'Speculation paused: file edit requires permission',
               'speculation_edit_boundary',
@@ -599,7 +624,10 @@ export async function startSpeculation(
             updateActiveSpeculationState(setAppState, () => ({
               boundary: { type: 'bash', command, completedAt: Date.now() },
             }))
-            abortController.abort()
+            requestSpeculationAbort(
+              abortController,
+              'speculation_bash_boundary',
+            )
             return denySpeculation(
               'Speculation paused: bash boundary',
               'speculation_bash_boundary',
@@ -633,7 +661,7 @@ export async function startSpeculation(
             completedAt: Date.now(),
           },
         }))
-        abortController.abort()
+        requestSpeculationAbort(abortController, 'speculation_unknown_tool')
         return denySpeculation(
           `Tool ${tool.name} not allowed during speculation`,
           'speculation_unknown_tool',
@@ -647,7 +675,10 @@ export async function startSpeculation(
         if (msg.type === 'assistant' || msg.type === 'user') {
           messagesRef.current.push(msg)
           if (messagesRef.current.length >= MAX_SPECULATION_MESSAGES) {
-            abortController.abort()
+            requestSpeculationAbort(
+              abortController,
+              'speculation_message_limit',
+            )
           }
           if (isUserMessageWithArrayContent(msg)) {
             const newTools = count(
@@ -687,7 +718,7 @@ export async function startSpeculation(
       abortController,
     )
   } catch (error) {
-    abortController.abort()
+    requestSpeculationAbort(abortController, 'speculation_failure')
 
     if (error instanceof Error && error.name === 'AbortError') {
       safeRemoveOverlay(overlayPath)

src/services/api/claude.abortClassification.test.ts

@@ -83,6 +83,19 @@ describe('Claude stream abort classification wiring', () => {
     )
   })
 
+  test('does not infer user intent from an external AbortError while root is active', () => {
+    const activeRoot = new AbortController()
+    const externalAbort = new APIUserAbortError()
+
+    expect(activeRoot.signal.aborted).toBe(false)
+    expect(shouldCreateUserInterruptionMessage(activeRoot.signal.reason)).toBe(
+      false,
+    )
+    expect(
+      getClaudeStreamingAbortLogMessage(activeRoot.signal, externalAbort),
+    ).toBe('Streaming aborted by parent signal: Request was aborted.')
+  })
+
   test('labels expected side-task retry aborts without reclassifying user aborts', () => {
     const expectedAbort = new AbortController()
     expectedAbort.abort('agent-summary-superseded')

src/services/api/claude.lifecycle.test.ts

@@ -14,6 +14,10 @@ import { resetGrowthBook } from '../analytics/growthbook.js'
 import { getEmptyToolPermissionContext } from '../../Tool.js'
 import type { Message } from '../../types/message.js'
 import { QueryLifecycleOperationTracker } from '../../utils/queryLifecycle.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../../utils/interruptionTrace.js'
 import { asSystemPrompt } from '../../utils/systemPromptType.js'
 import {
   executeNonStreamingRequest,
@@ -39,6 +43,7 @@ const envKeys = [
   'CLAUDE_CODE_USE_OPENAI',
   'CLAUDE_CODE_USE_VERTEX',
   'CLAUDE_CODE_DISABLE_NONSTREAMING_FALLBACK',
+  'CLAUDE_DISABLE_STREAM_WATCHDOG',
   'CLAUDE_FEATURE_FLAGS_FILE',
   'CLAUDE_STREAM_IDLE_TIMEOUT_MS',
   'GEMINI_API_KEY',
@@ -46,6 +51,7 @@ const envKeys = [
   'OPENAI_API_KEY',
   'OPENAI_BASE_URL',
   'OPENAI_MODEL',
+  'OPENCLAUDE_INTERRUPT_TRACE',
   'OPENCLAUDE_MAX_RETRIES',
   'VCR_RECORD',
 ] as const
@@ -490,6 +496,8 @@ describe('Claude API lifecycle tracking', () => {
   test('preserves provider override and query source during 404 non-streaming fallback', async () => {
     setClientTestEnv()
     process.env.OPENCLAUDE_MAX_RETRIES = '0'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
     const queryLifecycle = new QueryLifecycleOperationTracker()
     const providerBaseURL = 'https://provider.example/v1'
     const requests: {
@@ -541,6 +549,13 @@ describe('Claude API lifecycle tracking', () => {
 
     for await (const message of generator) {
       messages.push(message)
+      if (
+        typeof message === 'object' &&
+        message !== null &&
+        (message as { type?: unknown }).type === 'assistant'
+      ) {
+        break
+      }
     }
 
     const streamingRequest = requests.find(request => request.stream === true)
@@ -562,6 +577,27 @@ describe('Claude API lifecycle tracking', () => {
       querySource: 'sdk',
     })
     expect(queryLifecycle.snapshot().apiCalls).toEqual([])
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const creationError = trace.find(
+      entry =>
+        entry.event === 'claude_stream.error' &&
+        entry.phase === 'stream_creation',
+    )
+    const fallbackStarted = trace.find(
+      entry => entry.event === 'claude_stream.fallback_started',
+    )
+    const fallbackSettled = trace.find(
+      entry => entry.event === 'claude_stream.fallback_settled',
+    )
+    expect(creationError).toBeDefined()
+    expect(fallbackStarted).toMatchObject({
+      trigger: '404_stream_creation',
+      causalEventId: creationError?.eventId,
+    })
+    expect(fallbackSettled).toMatchObject({
+      outcome: 'completed',
+      causalEventId: fallbackStarted?.eventId,
+    })
   })
 
   test('parent abort during OpenAI-compatible stream does not start non-streaming fallback', async () => {
@@ -658,9 +694,12 @@ describe('Claude API lifecycle tracking', () => {
 
   test('stream idle timeout respects disabled non-streaming fallback guard', async () => {
     setClientTestEnv()
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
     process.env.OPENCLAUDE_MAX_RETRIES = '0'
     process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = String(TEST_STREAM_IDLE_TIMEOUT_MS)
     process.env.CLAUDE_CODE_DISABLE_NONSTREAMING_FALLBACK = '1'
+    process.env.CLAUDE_DISABLE_STREAM_WATCHDOG = '1'
     const queryLifecycle = new QueryLifecycleOperationTracker()
     const parent = new AbortController()
     let fallbackRequests = 0
@@ -726,6 +765,17 @@ describe('Claude API lifecycle tracking', () => {
           JSON.stringify((message as { message?: { content?: unknown } }).message?.content).includes('Stream idle timeout'),
       ),
     ).toBe(true)
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const providerIdle = trace.find(
+      entry =>
+        entry.event === 'provider_stream.idle_timeout' &&
+        entry.transport === 'openai_chat_completions',
+    )
+    const claudeError = trace.find(
+      entry => entry.event === 'claude_stream.error',
+    )
+    expect(providerIdle).toBeDefined()
+    expect(claudeError?.causalEventId).toBe(providerIdle?.eventId)
   })
 
   test('tracks each non-streaming fallback request and clears it on success', async () => {

src/services/api/claude.streamWatchdog.test.ts

@@ -11,7 +11,7 @@ import type {
   BetaRawMessageStreamEvent,
 } from '@anthropic-ai/sdk/resources/beta/messages/messages.mjs'
 import type { Stream } from '@anthropic-ai/sdk/streaming.mjs'
-import { mkdtempSync, rmSync } from 'fs'
+import { mkdtempSync, readFileSync, rmSync } from 'fs'
 import { tmpdir } from 'os'
 import { join } from 'path'
 import {
@@ -22,6 +22,13 @@ import { getEmptyToolPermissionContext } from '../../Tool.js'
 import type { Message } from '../../types/message.js'
 import { asSystemPrompt } from '../../utils/systemPromptType.js'
 import { QueryLifecycleOperationTracker } from '../../utils/queryLifecycle.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  registerInterruptionController,
+  requestAbort,
+} from '../../utils/interruptionTrace.js'
 import { EMPTY_USAGE } from './emptyUsage.js'
 import type { Options } from './claude.js'
 
@@ -39,6 +46,8 @@ const envKeys = [
   'CLAUDE_ENABLE_STREAM_WATCHDOG',
   'CLAUDE_STREAM_IDLE_TIMEOUT_MS',
   'OPENCLAUDE_MAX_RETRIES',
+  'OPENCLAUDE_INTERRUPT_TRACE',
+  'OPENCLAUDE_INTERRUPT_TRACE_FILE',
   'VCR_RECORD',
 ] as const
 
@@ -295,6 +304,8 @@ beforeEach(async () => {
   await acquireSharedMutationLock('claude.streamWatchdog.test.ts')
   installClientSpy()
   setTestMacro()
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
   for (const key of envKeys) {
     delete process.env[key]
   }
@@ -306,11 +317,13 @@ beforeEach(async () => {
   process.env.VCR_RECORD = '1'
 })
 
-afterEach(() => {
+afterEach(async () => {
   try {
     restoreClientSpy?.()
     restoreClientSpy = undefined
     createHandler = undefined
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
     for (const key of envKeys) {
       const envKey: string = key
       if (
@@ -343,6 +356,9 @@ afterEach(() => {
 
 describe('Claude stream watchdog', () => {
   test('falls back when the top-level stream iterator never settles', async () => {
+    const traceFile = join(fixturesRoot!, 'interruption-trace.jsonl')
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = traceFile
     const wedged = makeWedgedStream()
     const streamModes: unknown[] = []
     createHandler = params => {
@@ -369,6 +385,64 @@ describe('Claude stream watchdog', () => {
       expect(streamModes).toEqual([true, undefined])
       expect(wedged.abortSignal.aborted).toBe(true)
       expect(wedged.returnCalled()).toBe(true)
+      await __waitForInterruptionTraceFlushForTests()
+      const trace = readFileSync(traceFile, 'utf8')
+        .trim()
+        .split('\n')
+        .map(line => JSON.parse(line) as {
+          event: string
+          eventId?: string
+          causalEventId?: string
+          source?: string
+          outcome?: string
+        })
+      const events = trace.map(entry => entry.event)
+      expect(events.indexOf('claude_stream.idle_timeout')).toBeGreaterThanOrEqual(0)
+      expect(events.indexOf('claude_stream.loop_settled')).toBeGreaterThan(
+        events.indexOf('claude_stream.idle_timeout'),
+      )
+      expect(events.indexOf('claude_stream.fallback_started')).toBeGreaterThan(
+        events.indexOf('claude_stream.loop_settled'),
+      )
+      expect(trace).toContainEqual(
+        expect.objectContaining({
+          event: 'abort.requested',
+          source: 'claude_stream_watchdog',
+        }),
+      )
+      const idleTimeout = trace.find(
+        entry => entry.event === 'claude_stream.idle_timeout',
+      )
+      const providerAbort = trace.find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'claude_stream_watchdog',
+      )
+      const loopSettled = trace.find(
+        entry => entry.event === 'claude_stream.loop_settled',
+      )
+      const fallbackStarted = trace.find(
+        entry => entry.event === 'claude_stream.fallback_started',
+      )
+      const fallbackSettled = trace.find(
+        entry => entry.event === 'claude_stream.fallback_settled',
+      )
+      expect(idleTimeout).toBeDefined()
+      expect(providerAbort).toBeDefined()
+      expect(loopSettled).toBeDefined()
+      expect(fallbackStarted).toBeDefined()
+      expect(fallbackSettled).toBeDefined()
+      expect(typeof idleTimeout!.eventId).toBe('string')
+      expect(typeof providerAbort!.causalEventId).toBe('string')
+      expect(typeof loopSettled!.causalEventId).toBe('string')
+      expect(typeof fallbackStarted!.causalEventId).toBe('string')
+      expect(providerAbort!.causalEventId).toBe(idleTimeout!.eventId)
+      expect(loopSettled!.causalEventId).toBe(idleTimeout!.eventId)
+      expect(fallbackStarted!.causalEventId).toBe(idleTimeout!.eventId)
+      expect(fallbackSettled).toMatchObject({
+        causalEventId: fallbackStarted!.eventId,
+        outcome: 'completed',
+      })
       expect(
         (result as unknown[]).some(
           message =>
@@ -385,8 +459,10 @@ describe('Claude stream watchdog', () => {
 
   test('does not attempt fallback when the parent signal aborts first', async () => {
     process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = '250'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
     const wedged = makeWedgedStream()
     const controller = new AbortController()
+    registerInterruptionController(controller, { controllerRole: 'query-root' })
     const streamModes: unknown[] = []
     createHandler = params => {
       streamModes.push(params.stream)
@@ -406,7 +482,10 @@ describe('Claude stream watchdog', () => {
         error instanceof Error ? error.name : String(error),
       )
     await wedged.nextStarted
-    controller.abort()
+    requestAbort(controller, undefined, {
+      source: 'cancel_keybinding',
+      controllerRole: 'query-root',
+    })
 
     try {
       const result = await Promise.race([request, delay(150)])
@@ -414,6 +493,97 @@ describe('Claude stream watchdog', () => {
       expect(streamModes).toEqual([true])
       expect(wedged.abortSignal.aborted).toBe(true)
       expect(wedged.returnCalled()).toBe(true)
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const rootAbort = trace.find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.controllerRole === 'query-root',
+      )
+      const parentAbort = trace.find(
+        entry => entry.event === 'claude_stream.parent_abort',
+      )
+      const providerAbort = trace.find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'claude_stream_parent',
+      )
+      expect(rootAbort).toBeDefined()
+      expect(parentAbort).toBeDefined()
+      expect(providerAbort).toBeDefined()
+      expect(typeof rootAbort!.eventId).toBe('string')
+      expect(typeof parentAbort!.eventId).toBe('string')
+      expect(typeof parentAbort!.causalEventId).toBe('string')
+      expect(typeof providerAbort!.causalEventId).toBe('string')
+      expect(parentAbort!.causalEventId).toBe(rootAbort!.eventId)
+      expect(providerAbort!.causalEventId).toBe(parentAbort!.eventId)
+    } finally {
+      wedged.rejectPendingNext(new Error('test cleanup'))
+      await settleForCleanup(request)
+    }
+  })
+
+  test('records a terminal failed outcome when non-streaming fallback rejects', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const wedged = makeWedgedStream()
+    createHandler = params => {
+      if (params.stream === true) return makeWithResponse(wedged.stream)
+      return Promise.reject(new Error('synthetic fallback failure'))
+    }
+
+    const request = collectStreamingMessages(
+      new AbortController().signal,
+      makeOptions(),
+    )
+    await wedged.nextStarted
+    try {
+      await Promise.race([request, delay(250)])
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const started = trace.find(
+        entry => entry.event === 'claude_stream.fallback_started',
+      )
+      const settled = trace.find(
+        entry => entry.event === 'claude_stream.fallback_settled',
+      )
+      expect(started).toBeDefined()
+      expect(settled).toMatchObject({
+        outcome: 'failed',
+        causalEventId: started!.eventId,
+      })
+    } finally {
+      wedged.rejectPendingNext(new Error('test cleanup'))
+      await settleForCleanup(request)
+    }
+  })
+
+  test('records fallback failure when the returned message cannot be normalized', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const wedged = makeWedgedStream()
+    createHandler = params => {
+      if (params.stream === true) return makeWithResponse(wedged.stream)
+      return Promise.resolve(
+        makeBetaMessage('msg-invalid-fallback', [null] as never),
+      )
+    }
+
+    const request = collectStreamingMessages(
+      new AbortController().signal,
+      makeOptions(),
+    )
+    await wedged.nextStarted
+    try {
+      const result = await Promise.race([
+        request.then(
+          () => 'resolved',
+          error => error,
+        ),
+        delay(250),
+      ])
+      expect(result).not.toBe('timeout')
+      const settlements = __getInterruptionTraceSnapshotForTests().filter(
+        entry => entry.event === 'claude_stream.fallback_settled',
+      )
+      expect(settlements).toHaveLength(1)
+      expect(settlements[0]?.outcome).toBe('failed')
     } finally {
       wedged.rejectPendingNext(new Error('test cleanup'))
       await settleForCleanup(request)

src/services/api/claude.ts

@@ -175,6 +175,13 @@ import { CHROME_TOOL_SEARCH_INSTRUCTIONS } from 'src/utils/claudeInChrome/prompt
 import { COMPACT_MAX_OUTPUT_TOKENS, getContextWindowForModel, getMaxThinkingTokensForModel } from 'src/utils/context.js'
 import { logForDebugging } from 'src/utils/debug.js'
 import { logForDiagnosticsNoPII } from 'src/utils/diagLogs.js'
+import {
+  flushInterruptionTrace,
+  getInterruptionErrorCausalEventId,
+  getInterruptionSignalAbortEventId,
+  requestAbort,
+  traceInterruptionEvent,
+} from 'src/utils/interruptionTrace.js'
 import { type EffortValue, modelSupportsEffort } from 'src/utils/effort.js'
 import type { QueryLifecycleOperationTracker } from 'src/utils/queryLifecycle.js'
 import {
@@ -1157,6 +1164,21 @@ async function* queryModel(
   void
 > {
   const providerRequestModel = options.requestModel ?? options.model
+  function traceFallbackSettlement(
+    outcome: 'superseded' | 'aborted' | 'failed' | 'completed',
+    causalEventId: string | undefined,
+    error?: unknown,
+  ): void {
+    traceInterruptionEvent('claude_stream.fallback_settled', {
+      subsystem: 'claude_stream',
+      transport: 'anthropic_messages',
+      model: options.model,
+      outcome,
+      causalEventId,
+      ...(error === undefined ? {} : { error }),
+    })
+    flushInterruptionTrace('claude_stream_fallback_settled')
+  }
   // Check cheap conditions first — the off-switch await blocks on GrowthBook
   // init (~10ms). For non-Opus models (haiku, sonnet) this skips the await
   // entirely. Subscribers don't hit this path at all.
@@ -2101,6 +2123,7 @@ async function* queryModel(
     const STREAM_IDLE_TIMEOUT_MS = getStreamIdleTimeoutMs()
     const STREAM_IDLE_WARNING_MS = STREAM_IDLE_TIMEOUT_MS / 2
     let streamIdleAborted = false
+    let streamSettlementCausalEventId: string | undefined
     // performance.now() snapshot when watchdog fires, for measuring abort propagation delay
     let streamWatchdogFiredAt: number | null = null
     let streamIdleWarningTimer: ReturnType<typeof setTimeout> | null = null
@@ -2123,19 +2146,36 @@ async function* queryModel(
         { level: 'warn' },
       )
       logForDiagnosticsNoPII('warn', 'cli_streaming_idle_warning')
+      traceInterruptionEvent('claude_stream.idle_warning', {
+        subsystem: 'claude_stream',
+        transport: 'anthropic_messages',
+        model: options.model,
+        sinceLastYieldMs: warnMs,
+      })
     }
 
     function closeStreamIterator(
       iterator: AsyncIterator<BetaRawMessageStreamEvent>,
       reason: Error,
+      source: 'claude_stream_watchdog' | 'claude_stream_parent',
+      causalEventId?: string,
     ): void {
       const activeStream = stream
-      releaseStreamResources()
       try {
-        activeStream?.controller?.abort(reason)
+        if (activeStream?.controller) {
+          requestAbort(activeStream.controller, reason, {
+            source,
+            causalEventId,
+            subsystem: 'claude_stream',
+            transport: 'anthropic_messages',
+            model: options.model,
+            controllerRole: 'provider-stream',
+          })
+        }
       } catch {
         // Ignore - the stream may already be closed by the SDK.
       }
+      releaseStreamResources()
 
       try {
         const returned = iterator.return?.()
@@ -2158,6 +2198,14 @@ async function* queryModel(
         { level: 'error' },
       )
       logForDiagnosticsNoPII('error', 'cli_streaming_idle_timeout')
+      const causalEventId = traceInterruptionEvent('claude_stream.idle_timeout', {
+        subsystem: 'claude_stream',
+        transport: 'anthropic_messages',
+        model: options.model,
+        sinceLastYieldMs: STREAM_IDLE_TIMEOUT_MS,
+      })
+      streamSettlementCausalEventId = causalEventId
+      flushInterruptionTrace('claude_stream_idle_timeout')
       logEvent('tengu_streaming_idle_timeout', {
         model:
           options.model as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
@@ -2166,7 +2214,12 @@ async function* queryModel(
         timeout_ms: STREAM_IDLE_TIMEOUT_MS,
       })
 
-      closeStreamIterator(iterator, timeoutError)
+      closeStreamIterator(
+        iterator,
+        timeoutError,
+        'claude_stream_watchdog',
+        causalEventId,
+      )
     }
 
     function readNextStreamPart(
@@ -2174,7 +2227,14 @@ async function* queryModel(
     ): Promise<IteratorResult<BetaRawMessageStreamEvent>> {
       if (signal.aborted) {
         const abortError = new APIUserAbortError()
-        closeStreamIterator(iterator, abortError)
+        streamSettlementCausalEventId =
+          getInterruptionSignalAbortEventId(signal)
+        closeStreamIterator(
+          iterator,
+          abortError,
+          'claude_stream_parent',
+          getInterruptionSignalAbortEventId(signal),
+        )
         return Promise.reject(abortError)
       }
 
@@ -2200,7 +2260,22 @@ async function* queryModel(
         }
         const onAbort = () => {
           const abortError = new APIUserAbortError()
-          closeStreamIterator(iterator, abortError)
+          const parentCausalEventId = getInterruptionSignalAbortEventId(signal)
+          const causalEventId = traceInterruptionEvent('claude_stream.parent_abort', {
+            subsystem: 'claude_stream',
+            transport: 'anthropic_messages',
+            model: options.model,
+            reason: signal.reason,
+            causalEventId: parentCausalEventId,
+          })
+          streamSettlementCausalEventId =
+            causalEventId ?? parentCausalEventId
+          closeStreamIterator(
+            iterator,
+            abortError,
+            'claude_stream_parent',
+            causalEventId ?? parentCausalEventId,
+          )
           settleReject(abortError)
         }
 
@@ -2630,6 +2705,14 @@ async function* queryModel(
           streamWatchdogFiredAt !== null
             ? Math.round(performance.now() - streamWatchdogFiredAt)
             : -1
+        traceInterruptionEvent('claude_stream.loop_settled', {
+          subsystem: 'claude_stream',
+          transport: 'anthropic_messages',
+          model: options.model,
+          outcome: 'clean',
+          causalEventId: streamSettlementCausalEventId,
+          sinceLastYieldMs: exitDelayMs,
+        })
         logForDiagnosticsNoPII(
           'info',
           'cli_stream_loop_exited_after_watchdog_clean',
@@ -2719,6 +2802,20 @@ async function* queryModel(
     } catch (streamingError) {
       // Clear the idle timeout watchdog on error path too
       clearStreamIdleTimers()
+      streamSettlementCausalEventId =
+        getInterruptionErrorCausalEventId(streamingError) ??
+        streamSettlementCausalEventId
+      traceInterruptionEvent('claude_stream.error', {
+        subsystem: 'claude_stream',
+        transport: 'anthropic_messages',
+        model: options.model,
+        outcome: signal.aborted ? 'root_aborted' : 'external_error',
+        reason: signal.reason,
+        causalEventId:
+          getInterruptionSignalAbortEventId(signal) ??
+          streamSettlementCausalEventId,
+        error: streamingError,
+      })
 
       // Instrumentation: if the watchdog had already fired and the for-await
       // threw (rather than exiting cleanly), record that the loop DID exit and
@@ -2727,6 +2824,15 @@ async function* queryModel(
         const exitDelayMs = Math.round(
           performance.now() - streamWatchdogFiredAt,
         )
+        traceInterruptionEvent('claude_stream.loop_settled', {
+          subsystem: 'claude_stream',
+          transport: 'anthropic_messages',
+          model: options.model,
+          outcome: 'error',
+          causalEventId: streamSettlementCausalEventId,
+          error: streamingError,
+          sinceLastYieldMs: exitDelayMs,
+        })
         logForDiagnosticsNoPII(
           'info',
           'cli_stream_loop_exited_after_watchdog_error',
@@ -2862,6 +2968,16 @@ async function* queryModel(
       // Instrumentation: proves executeNonStreamingRequest was entered (vs. the
       // fallback event firing but the call itself hanging at dispatch).
       logForDiagnosticsNoPII('info', 'cli_nonstreaming_fallback_started')
+      const fallbackStartedEventId = traceInterruptionEvent(
+        'claude_stream.fallback_started', {
+        subsystem: 'claude_stream',
+        transport: 'anthropic_messages',
+        model: options.model,
+        trigger: streamIdleAborted ? 'watchdog' : 'other',
+        causalEventId: streamSettlementCausalEventId,
+        },
+      )
+      flushInterruptionTrace('claude_stream_fallback_started')
       logEvent('tengu_nonstreaming_fallback_started', {
         request_id: (streamRequestId ??
           'unknown') as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
@@ -2872,7 +2988,10 @@ async function* queryModel(
           : 'other') as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
       })
       endActiveApiCall()
-      const result = yield* executeNonStreamingRequest(
+      let result: BetaMessage | null
+      let fallbackResultMessage: AssistantMessage | undefined
+      try {
+        result = yield* executeNonStreamingRequest(
           { model: providerRequestModel, source: options.querySource, providerOverride: options.providerOverride, effortValue: effort },
           {
             model: providerRequestModel,
@@ -2894,9 +3013,12 @@ async function* queryModel(
           options.onProviderRequestStart,
         )
 
-      if (result === null) return
+        if (result === null) {
+          traceFallbackSettlement('superseded', fallbackStartedEventId)
+          return
+        }
 
-      const m: AssistantMessage = {
+        fallbackResultMessage = {
           message: {
             ...result,
             content: normalizeContentFromAPI(
@@ -2917,9 +3039,18 @@ async function* queryModel(
             advisorModel,
           }),
         }
-      newMessages.push(m)
+        newMessages.push(fallbackResultMessage)
-      fallbackMessage = m
+        fallbackMessage = fallbackResultMessage
-      yield m
+      } catch (error) {
+        traceFallbackSettlement(
+          signal.aborted ? 'aborted' : 'failed',
+          fallbackStartedEventId,
+          error,
+        )
+        throw error
+      }
+      traceFallbackSettlement('completed', fallbackStartedEventId)
+      yield fallbackResultMessage
     } finally {
       clearStreamIdleTimers()
     }
@@ -2959,6 +3090,16 @@ async function* queryModel(
       errorFromRetry.originalError.status === 404
 
     if (is404StreamCreationError) {
+      const streamCreationErrorEventId = traceInterruptionEvent(
+        'claude_stream.error',
+        {
+          subsystem: 'claude_stream',
+          phase: 'stream_creation',
+          transport: 'anthropic_messages',
+          model: options.model,
+          error: errorFromRetry,
+        },
+      )
       // 404 is thrown at .withResponse() before streamRequestId is assigned,
       // and CannotRetryError means every retry failed — so grab the failed
       // request's ID from the error header instead.
@@ -2988,6 +3129,18 @@ async function* queryModel(
           '404_stream_creation' as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
       })
 
+      const fallbackStartedEventId = traceInterruptionEvent(
+        'claude_stream.fallback_started',
+        {
+          subsystem: 'claude_stream',
+          transport: 'anthropic_messages',
+          model: options.model,
+          trigger: '404_stream_creation',
+          causalEventId: streamCreationErrorEventId,
+        },
+      )
+      flushInterruptionTrace('claude_stream_fallback_started')
+
       try {
         // Fall back to non-streaming mode
         endActiveApiCall()
@@ -3017,7 +3170,10 @@ async function* queryModel(
           options.onProviderRequestStart,
         )
 
-        if (result === null) return
+        if (result === null) {
+          traceFallbackSettlement('superseded', fallbackStartedEventId)
+          return
+        }
 
         const m: AssistantMessage = {
           message: {
@@ -3038,10 +3194,16 @@ async function* queryModel(
         }
         newMessages.push(m)
         fallbackMessage = m
+        traceFallbackSettlement('completed', fallbackStartedEventId)
         yield m
 
         // Continue to success logging below
       } catch (fallbackError) {
+        traceFallbackSettlement(
+          signal.aborted ? 'aborted' : 'failed',
+          fallbackStartedEventId,
+          fallbackError,
+        )
         // Propagate model-fallback signal to query.ts (see comment above).
         if (fallbackError instanceof FallbackTriggeredError) {
           throw fallbackError
@@ -3265,7 +3427,11 @@ export function cleanupStream(
   try {
     // Abort the stream via its controller if not already aborted
     if (!stream.controller.signal.aborted) {
-      stream.controller.abort()
+      requestAbort(stream.controller, undefined, {
+        source: 'claude_stream_cleanup',
+        subsystem: 'claude_stream',
+        controllerRole: 'provider-stream',
+      })
     }
   } catch {
     // Ignore - stream may already be closed

src/services/api/codexShim.interruption.test.ts

@@ -0,0 +1,841 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
+import type { AnthropicStreamEvent } from './codexShim.js'
+import {
+  __codexStreamToAnthropicForTests,
+  codexStreamToAnthropic,
+} from './codexShim.js'
+import { QueryGuard, type QueryGuardTimeoutReason } from '../../utils/QueryGuard.js'
+import type { QueryGuardTimeoutInfo } from '../../utils/queryLifecycle.js'
+import { driveQueryEvents } from '../../utils/queryEventDriver.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  requestAbort,
+} from '../../utils/interruptionTrace.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('codexShim.interruption.test.ts')
+})
+
+afterEach(async () => {
+  try {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+async function bounded<T>(promise: Promise<T>, timeoutMs = 2_000): Promise<T> {
+  let timer: ReturnType<typeof setTimeout> | undefined
+  try {
+    return await Promise.race([
+      promise,
+      new Promise<T>((_, reject) => {
+        timer = setTimeout(
+          () => reject(new Error('issue-1830 test did not settle')),
+          timeoutMs,
+        )
+      }),
+    ])
+  } finally {
+    if (timer !== undefined) clearTimeout(timer)
+  }
+}
+
+function responseFromText(text: string): Response {
+  const encoder = new TextEncoder()
+  return new Response(
+    new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(encoder.encode(text))
+        controller.close()
+      },
+    }),
+  )
+}
+
+async function collectCodex(response: Response): Promise<AnthropicStreamEvent[]> {
+  const events: AnthropicStreamEvent[] = []
+  for await (const event of codexStreamToAnthropic(response, 'gpt-test')) {
+    events.push(event)
+  }
+  return events
+}
+
+function makeTimedStream(
+  makeFrame: (index: number) => string,
+  intervalMs: number,
+): {
+  response: Response
+  cancelReasons: unknown[]
+  getEmissionCount: () => number
+  stop: () => void
+} {
+  const cancelReasons: unknown[] = []
+  const encoder = new TextEncoder()
+  let index = 0
+  let timer: ReturnType<typeof setInterval> | undefined
+  let stopped = false
+  let streamController: ReadableStreamDefaultController<Uint8Array> | undefined
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      streamController = controller
+      timer = setInterval(() => {
+        if (stopped) return
+        try {
+          controller.enqueue(encoder.encode(makeFrame(index++)))
+        } catch {
+          stopped = true
+        }
+      }, intervalMs)
+    },
+    cancel(reason) {
+      stopped = true
+      if (timer !== undefined) clearInterval(timer)
+      cancelReasons.push(reason)
+    },
+  })
+  return {
+    response: new Response(stream),
+    cancelReasons,
+    getEmissionCount: () => index,
+    stop: () => {
+      stopped = true
+      if (timer !== undefined) clearInterval(timer)
+      try {
+        streamController?.close()
+      } catch {
+        // The production reader may already have cancelled the stream.
+      }
+    },
+  }
+}
+
+async function driveWithGuard(
+  response: Response,
+  options: {
+    idleTimeoutMs: number
+    hardMaxQueryMs: number
+    /** Raw-reader deadline, intentionally distinct from QueryGuard activity. */
+    readerIdleTimeoutMs: number
+  },
+): Promise<{
+  events: AnthropicStreamEvent[]
+  timeout: QueryGuardTimeoutInfo
+  result: { status: 'resolved' } | { status: 'rejected'; error: unknown }
+  signalReason: unknown
+}> {
+  const controller = new AbortController()
+  const guard = new QueryGuard(options)
+  const start = guard.tryStart({
+    queryId: 'issue-1830-query',
+    querySource: 'issue-1830-test',
+  })
+  if (!start) throw new Error('QueryGuard did not start')
+  let timeout: QueryGuardTimeoutInfo | undefined
+  guard.setTimeoutHandler(info => {
+    timeout = info
+    requestAbort(controller, info.context.terminalReason, {
+      source: 'query_guard',
+      subsystem: 'issue_1830_test',
+      controllerRole: 'query-root',
+      causalEventId: info.causalEventId,
+    })
+  })
+  const events: AnthropicStreamEvent[] = []
+  const stream = __codexStreamToAnthropicForTests(
+    response,
+    'gpt-test',
+    controller.signal,
+    { idleTimeoutMs: options.readerIdleTimeoutMs },
+  )
+  try {
+    const result = await bounded(
+      driveQueryEvents(
+        stream,
+        reason => guard.registerActivity(reason, start.generation),
+        event => events.push(event),
+      ).then(
+        () => ({ status: 'resolved' as const }),
+        error => ({ status: 'rejected' as const, error }),
+      ),
+    )
+    if (!timeout) throw new Error('QueryGuard did not own the terminal decision')
+    return { events, timeout, result, signalReason: controller.signal.reason }
+  } finally {
+    if (!controller.signal.aborted) {
+      requestAbort(controller, 'test-cleanup', {
+        source: 'issue_1830_test_cleanup',
+        subsystem: 'issue_1830_test',
+        controllerRole: 'query-root',
+      })
+    }
+    guard.forceEnd('unknown', 'test-cleanup')
+    await bounded(stream.return(undefined), 100).catch(() => {})
+  }
+}
+
+describe('issue #1830 Codex interruption ownership', () => {
+  test('raw transport silence is owned by the Codex reader deadline', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const cancelReasons: unknown[] = []
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        cancel(reason) {
+          cancelReasons.push(reason)
+        },
+      }),
+    )
+    const iterator = __codexStreamToAnthropicForTests(
+      response,
+      'gpt-test',
+      undefined,
+      { idleTimeoutMs: 25 },
+    )[Symbol.asyncIterator]()
+
+    try {
+      expect((await bounded(iterator.next())).value?.type).toBe('message_start')
+      const result = await bounded(
+        iterator.next().then(
+          value => ({ status: 'resolved' as const, value }),
+          error => ({ status: 'rejected' as const, error }),
+        ),
+      )
+
+      expect(result.status).toBe('rejected')
+      if (result.status === 'rejected') {
+        expect((result.error as Error).message).toContain(
+          'Codex SSE stream idle',
+        )
+      }
+      expect(cancelReasons).toHaveLength(1)
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const idleTimeout = trace.find(
+        entry => entry.event === 'codex_stream.idle_timeout',
+      )
+      const readerError = trace.find(
+        entry => entry.event === 'codex_stream.error',
+      )
+      const readerCancelled = trace.find(
+        entry => entry.event === 'codex_stream.cancelled',
+      )
+      const converterClosed = trace.find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )
+      expect(idleTimeout).toBeDefined()
+      expect(readerError).toBeDefined()
+      expect(readerCancelled).toBeDefined()
+      expect(converterClosed).toBeDefined()
+      expect(typeof idleTimeout!.eventId).toBe('string')
+      expect(typeof readerError!.causalEventId).toBe('string')
+      expect(typeof readerCancelled!.causalEventId).toBe('string')
+      expect(typeof converterClosed!.causalEventId).toBe('string')
+      expect(readerError!.causalEventId).toBe(idleTimeout!.eventId)
+      expect(readerCancelled!.causalEventId).toBe(idleTimeout!.eventId)
+      expect(converterClosed!.causalEventId).toBe(idleTimeout!.eventId)
+    } finally {
+      const returned = iterator.return?.(undefined)
+      if (returned) await bounded(Promise.resolve(returned), 100).catch(() => {})
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
+  test('parent abort settles the pending read before its idle deadline', async () => {
+    const cancelReasons: unknown[] = []
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        cancel(reason) {
+          cancelReasons.push(reason)
+        },
+      }),
+    )
+    const controller = new AbortController()
+    const iterator = __codexStreamToAnthropicForTests(
+      response,
+      'gpt-test',
+      controller.signal,
+      { idleTimeoutMs: 1_000 },
+    )[Symbol.asyncIterator]()
+    try {
+      expect((await bounded(iterator.next())).value?.type).toBe('message_start')
+
+      const pending = iterator.next().then(
+        value => ({ status: 'resolved' as const, value }),
+        error => ({ status: 'rejected' as const, error }),
+      )
+      controller.abort('query-timeout')
+      const result = await bounded(pending)
+
+      expect(controller.signal.reason).toBe('query-timeout')
+      expect(result.status).toBe('rejected')
+      if (result.status === 'rejected') {
+        expect((result.error as { name?: unknown }).name).toBe('AbortError')
+      }
+      expect(cancelReasons).toHaveLength(1)
+    } finally {
+      if (!controller.signal.aborted) controller.abort('test-cleanup')
+      const returned = iterator.return?.(undefined)
+      if (returned) await bounded(Promise.resolve(returned), 100).catch(() => {})
+    }
+  })
+
+  test('a done-only Codex stream completes without waiting for transport EOF', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const cancelReasons: unknown[] = []
+    const encoder = new TextEncoder()
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        start(controller) {
+          controller.enqueue(encoder.encode('data: [DONE]\n\n'))
+        },
+        cancel(reason) {
+          cancelReasons.push(reason)
+        },
+      }),
+    )
+
+    try {
+      const events: AnthropicStreamEvent[] = []
+      for await (const event of __codexStreamToAnthropicForTests(
+        response,
+        'gpt-test',
+        undefined,
+        { idleTimeoutMs: 25 },
+      )) {
+        events.push(event)
+      }
+      expect(events.at(-1)?.type).toBe('message_stop')
+      expect(
+        __getInterruptionTraceSnapshotForTests().some(
+          entry => entry.event === 'codex_stream.idle_timeout',
+        ),
+      ).toBe(false)
+      expect(cancelReasons).toHaveLength(1)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('normal completed and incomplete frames after a done marker close without interruption traces', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    try {
+      for (const terminalEvent of [
+        'response.completed',
+        'response.incomplete',
+      ]) {
+        __resetInterruptionTraceForTests()
+        const cancelReasons: unknown[] = []
+        const encoder = new TextEncoder()
+        const response = new Response(
+          new ReadableStream<Uint8Array>({
+            start(controller) {
+              controller.enqueue(new Uint8Array())
+              controller.enqueue(encoder.encode([
+                ': keepalive',
+                '',
+                'data: [DONE]',
+                '',
+                `event: ${terminalEvent}`,
+                `data: {"type":"${terminalEvent}","response":{"status":"${terminalEvent.slice('response.'.length)}","output":[]}}`,
+                '',
+                '',
+              ].join('\n')))
+            },
+            cancel(reason) {
+              cancelReasons.push(reason)
+            },
+          }),
+        )
+        const events: AnthropicStreamEvent[] = []
+        await bounded((async () => {
+          for await (const event of codexStreamToAnthropic(response, 'gpt-test')) {
+            events.push(event)
+          }
+        })())
+
+        expect(events.at(-1)?.type).toBe('message_stop')
+        const trace = __getInterruptionTraceSnapshotForTests()
+        const firstRawBytes = trace.filter(
+          entry => entry.event === 'codex_stream.first_raw_byte',
+        )
+        const terminal = trace.find(
+          entry =>
+            entry.event === 'codex_stream.protocol_terminal' &&
+            entry.phase === terminalEvent,
+        )
+        expect(firstRawBytes).toHaveLength(1)
+        expect(firstRawBytes[0]!.rawByteCount).toBeGreaterThan(0)
+        expect(terminal).toBeDefined()
+        expect(terminal!.controlFrameCount).toBe(2)
+        expect(terminal!.ignoredFrameCount).toBe(0)
+        expect(
+          trace.some(entry => entry.event === 'codex_stream.cancelled'),
+        ).toBe(false)
+        expect(cancelReasons).toHaveLength(1)
+      }
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
+  test('reports non-negative idle evidence and forwards its causal event id', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const causalEventIds: string[] = []
+    const encoder = new TextEncoder()
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        start(controller) {
+          controller.enqueue(encoder.encode(': keepalive\n\n'))
+        },
+      }),
+    )
+    const iterator = __codexStreamToAnthropicForTests(
+      response,
+      'gpt-test',
+      undefined,
+      {
+        idleTimeoutMs: 25,
+        onCausalEventId: eventId => causalEventIds.push(eventId),
+      },
+    )[Symbol.asyncIterator]()
+
+    try {
+      expect((await bounded(iterator.next())).value?.type).toBe('message_start')
+      const pending = iterator.next().catch(error => error)
+      await bounded(pending)
+
+      const idleTimeout = __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.idle_timeout',
+      )
+      expect(idleTimeout).toBeDefined()
+      expect(idleTimeout?.sinceLastRawByteMs).toBeGreaterThanOrEqual(0)
+      expect(idleTimeout?.sinceLastParsedFrameMs).toBeGreaterThanOrEqual(0)
+      expect(causalEventIds).toEqual([idleTimeout!.eventId])
+    } finally {
+      await bounded(iterator.return?.(undefined) ?? Promise.resolve()).catch(
+        () => {},
+      )
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('marks the converter complete before yielding message_stop', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const cancelReasons: unknown[] = []
+    const encoder = new TextEncoder()
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        start(controller) {
+          controller.enqueue(encoder.encode([
+            'event: response.completed',
+            'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+            '',
+            '',
+          ].join('\n')))
+        },
+        cancel(reason) {
+          cancelReasons.push(reason)
+        },
+      }),
+    )
+    const iterator = codexStreamToAnthropic(response, 'gpt-test')
+
+    try {
+      let next: IteratorResult<AnthropicStreamEvent>
+      do {
+        next = await bounded(iterator.next())
+      } while (!next.done && next.value.type !== 'message_stop')
+      expect(next.done).toBe(false)
+
+      await bounded(iterator.return(undefined))
+
+      const converterClosed = __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )
+      expect(converterClosed).toBeDefined()
+      expect(converterClosed!.outcome).toBe('complete')
+      expect(cancelReasons).toHaveLength(1)
+    } finally {
+      await bounded(iterator.return(undefined)).catch(() => {})
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
+  test('reports root_aborted when cancellation follows terminal evidence', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const controller = new AbortController()
+    const response = responseFromText([
+      'event: response.completed',
+      'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+      '',
+      '',
+    ].join('\n'))
+    const iterator = codexStreamToAnthropic(
+      response,
+      'gpt-test',
+      controller.signal,
+    )
+
+    let next: IteratorResult<AnthropicStreamEvent>
+    do {
+      next = await bounded(iterator.next())
+    } while (!next.done && next.value.type !== 'message_stop')
+    expect(next.done).toBe(false)
+
+    requestAbort(controller, undefined, {
+      source: 'test_root_abort',
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
+    await bounded(iterator.return(undefined))
+
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )?.outcome,
+    ).toBe('root_aborted')
+  })
+
+  test('keeps terminal ownership when the consumer returns after message_delta', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const response = responseFromText([
+      'event: response.completed',
+      'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+      '',
+      '',
+    ].join('\n'))
+    const iterator = codexStreamToAnthropic(response, 'gpt-test')
+
+    try {
+      let next: IteratorResult<AnthropicStreamEvent>
+      do {
+        next = await bounded(iterator.next())
+      } while (!next.done && next.value.type !== 'message_delta')
+      expect(next.done).toBe(false)
+      await bounded(iterator.return(undefined))
+
+      const converterClosed = __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )
+      expect(converterClosed?.outcome).toBe('complete')
+    } finally {
+      await bounded(iterator.return(undefined)).catch(() => {})
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('classifies each Codex reader and converter frame exactly once', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const text = [
+      ': keepalive',
+      '',
+      'event: response.created',
+      'data: not-json',
+      '',
+      'event: response.created',
+      'data: []',
+      '',
+      'event: response.created',
+      'data: {"type":"response.created","sequence_number":1}',
+      '',
+      'data: [DONE]',
+      '',
+      'event: response.completed',
+      'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+      '',
+      '',
+    ].join('\n')
+
+    try {
+      await bounded((async () => {
+        for await (const _event of codexStreamToAnthropic(
+          responseFromText(text),
+          'gpt-test',
+        )) {
+          // Drain the converter to terminal diagnostics.
+        }
+      })())
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const terminal = trace.find(
+        entry => entry.event === 'codex_stream.protocol_terminal',
+      )
+      const converterClosed = trace.find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )
+      expect(terminal).toMatchObject({
+        rawByteCount: new TextEncoder().encode(text).byteLength,
+        parsedFrameCount: 2,
+        controlFrameCount: 2,
+        ignoredFrameCount: 2,
+      })
+      expect(converterClosed?.ignoredParsedFrameCount).toBe(1)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('classifies event-only and typed data-only frames without inflating ignored input', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const text = [
+      'event: ping',
+      '',
+      'data: {"type":"response.created","sequence_number":1}',
+      '',
+      'event: response.completed',
+      'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+      '',
+      '',
+    ].join('\n')
+
+    try {
+      await collectCodex(responseFromText(text))
+      const terminal = __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.protocol_terminal',
+      )
+      expect(terminal).toMatchObject({
+        parsedFrameCount: 2,
+        controlFrameCount: 1,
+        ignoredFrameCount: 0,
+      })
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('reports parsed-but-unhandled converter events with a distinct counter', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const encoder = new TextEncoder()
+    const response = new Response(
+      new ReadableStream<Uint8Array>({
+        start(controller) {
+          controller.enqueue(encoder.encode([
+            'event: response.created',
+            'data: {"type":"response.created","sequence_number":1}',
+            '',
+            'event: response.completed',
+            'data: {"type":"response.completed","response":{"status":"completed","output":[]}}',
+            '',
+            '',
+          ].join('\n')))
+        },
+      }),
+    )
+
+    try {
+      await bounded((async () => {
+        for await (const _event of codexStreamToAnthropic(response, 'gpt-test')) {
+          // Drain the converter to its terminal diagnostics.
+        }
+      })())
+
+      const converterClosed = __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'codex_stream.converter_closed',
+      )
+      expect(converterClosed?.ignoredParsedFrameCount).toBe(1)
+      expect(converterClosed?.ignoredFrameCount).toBeUndefined()
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
+
+  test('keepalives and parsed-but-ignored frames cannot reset QueryGuard', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const timed = makeTimedStream(
+      index => {
+        if (index % 4 === 0) return ': keepalive\n\n'
+        if (index % 4 === 1) {
+          return `event: response.created\ndata: {"type":"response.created","sequence_number":${index}}\n\n`
+        }
+        if (index % 4 === 2) {
+          return 'event: response.created\ndata: []\n\n'
+        }
+        return `event: response.reasoning_summary_text.delta\ndata: {"type":"response.reasoning_summary_text.delta","delta":"r","sequence_number":${index}}\n\n`
+      },
+      25,
+    )
+    try {
+      const outcome = await driveWithGuard(timed.response, {
+        idleTimeoutMs: 250,
+        hardMaxQueryMs: 1_500,
+        readerIdleTimeoutMs: 500,
+      })
+
+      expect(outcome.timeout.reason satisfies QueryGuardTimeoutReason).toBe(
+        'idle',
+      )
+      expect(outcome.signalReason).toBe('query-timeout')
+      expect(outcome.result.status).toBe('rejected')
+      expect(outcome.events.map(event => event.type)).toEqual([
+        'message_start',
+      ])
+      const readerClosed = __getInterruptionTraceSnapshotForTests()
+        .filter(entry => entry.event === 'codex_stream.cancelled')
+        .at(-1)
+      const rootAbort = __getInterruptionTraceSnapshotForTests().find(
+        entry =>
+          entry.event === 'abort.requested' && entry.source === 'query_guard',
+      )
+      const traceEvents = __getInterruptionTraceSnapshotForTests().map(
+        entry => entry.event,
+      )
+      expect(timed.getEmissionCount()).toBeGreaterThan(3)
+      expect(readerClosed?.rawByteCount).toBeGreaterThan(0)
+      expect(readerClosed?.parsedFrameCount).toBeGreaterThan(0)
+      expect(readerClosed?.controlFrameCount).toBeGreaterThan(0)
+      expect(readerClosed?.ignoredFrameCount).toBeGreaterThan(0)
+      const converterClosed = __getInterruptionTraceSnapshotForTests()
+        .filter(entry => entry.event === 'codex_stream.converter_closed')
+        .at(-1)
+      expect(converterClosed?.ignoredParsedFrameCount).toBeGreaterThan(0)
+      expect(converterClosed?.ignoredFrameCount).toBeUndefined()
+      expect(rootAbort).toBeDefined()
+      expect(readerClosed).toBeDefined()
+      expect(typeof rootAbort!.eventId).toBe('string')
+      expect(typeof readerClosed!.causalEventId).toBe('string')
+      expect(readerClosed!.causalEventId).toBe(rootAbort!.eventId)
+      expect(traceEvents.indexOf('codex_stream.converter_closed')).toBeGreaterThan(
+        traceEvents.indexOf('codex_stream.cancelled'),
+      )
+      expect(timed.cancelReasons).toHaveLength(1)
+    } finally {
+      timed.stop()
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
+  test('valid deltas extend idle activity but cannot bypass the hard maximum', async () => {
+    const timed = makeTimedStream(
+      index =>
+        `event: response.output_text.delta\ndata: {"type":"response.output_text.delta","delta":"x","sequence_number":${index}}\n\n`,
+      25,
+    )
+    try {
+      const outcome = await driveWithGuard(timed.response, {
+        idleTimeoutMs: 250,
+        hardMaxQueryMs: 600,
+        readerIdleTimeoutMs: 500,
+      })
+      const countAtAbort = outcome.events.length
+      await Bun.sleep(30)
+
+      expect(outcome.timeout.reason satisfies QueryGuardTimeoutReason).toBe(
+        'hard_max',
+      )
+      expect(outcome.signalReason).toBe('hard-max-query-timeout')
+      expect(outcome.result.status).toBe('rejected')
+      expect(countAtAbort).toBeGreaterThan(3)
+      expect(outcome.events).toHaveLength(countAtAbort)
+      expect(timed.cancelReasons).toHaveLength(1)
+    } finally {
+      timed.stop()
+    }
+  })
+
+  test('repeated pending-read abort cycles cancel exactly once', async () => {
+    for (let cycle = 0; cycle < 40; cycle++) {
+      const cancelReasons: unknown[] = []
+      const response = new Response(
+        new ReadableStream<Uint8Array>({
+          cancel(reason) {
+            cancelReasons.push(reason)
+          },
+        }),
+      )
+      const controller = new AbortController()
+      const iterator = __codexStreamToAnthropicForTests(
+        response,
+        'gpt-test',
+        controller.signal,
+        { idleTimeoutMs: 1_000 },
+      )[Symbol.asyncIterator]()
+      try {
+        expect((await bounded(iterator.next())).value?.type).toBe(
+          'message_start',
+        )
+        const pending = iterator.next().catch(error => error as unknown)
+        controller.abort('user-cancel')
+        await bounded(pending)
+        expect(cancelReasons).toHaveLength(1)
+      } finally {
+        if (!controller.signal.aborted) controller.abort('test-cleanup')
+        const returned = iterator.return?.(undefined)
+        if (returned) {
+          await bounded(Promise.resolve(returned), 100).catch(() => {})
+        }
+      }
+    }
+  })
+})

src/services/api/codexShim.ts

@@ -12,6 +12,18 @@ import {
   createThinkTagFilter,
   stripThinkTags,
 } from './thinkTagSanitizer.js'
+import {
+  createReaderCanceller,
+  createStreamAbortError,
+  readWithIdleTimeout,
+  throwIfStreamAborted,
+} from './openaiShim/streamControl.js'
+import {
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  setInterruptionErrorCausalEventId,
+  traceInterruptionEvent,
+} from '../../utils/interruptionTrace.js'
 
 export interface AnthropicUsage {
   input_tokens: number
@@ -81,42 +93,6 @@ type CodexSseEvent = {
   data: Record<string, any>
 }
 
-function createStreamAbortError(): DOMException {
-  return new DOMException('Aborted', 'AbortError')
-}
-
-function throwIfStreamAborted(signal?: AbortSignal): void {
-  if (signal?.aborted) {
-    throw createStreamAbortError()
-  }
-}
-
-function createReaderCanceller(
-  reader: ReadableStreamDefaultReader<Uint8Array>,
-  signal?: AbortSignal,
-): {
-    cancel: (error?: unknown) => void
-    cleanup: () => void
-  } {
-  let cancelled = false
-  const cancel = (error: unknown = createStreamAbortError()) => {
-    if (cancelled) return
-    cancelled = true
-    void reader.cancel(error).catch(() => {})
-  }
-  const onAbort = () => cancel(createStreamAbortError())
-
-  signal?.addEventListener('abort', onAbort, { once: true })
-  if (signal?.aborted) {
-    onAbort()
-  }
-
-  return {
-    cancel,
-    cleanup: () => signal?.removeEventListener('abort', onAbort),
-  }
-}
-
 function makeUsage(usage?: Record<string, unknown>): AnthropicUsage {
   // Single source of truth for raw → Anthropic shape. Lives in
   // cacheMetrics.ts alongside the raw-shape extractor so any new
@@ -708,83 +684,108 @@ export async function performCodexRequest(options: {
   return response
 }
 
-async function* readSseEvents(response: Response, signal?: AbortSignal): AsyncGenerator<CodexSseEvent> {
+type CodexStreamReadOptions = {
+  /** Internal deterministic-test seam; production keeps the 120-second owner. */
+  idleTimeoutMs?: number
+  onCausalEventId?: (eventId: string) => void
+}
+
+const STREAM_IDLE_TIMEOUT_MS = 120_000
+
+async function* readSseEvents(
+  response: Response,
+  signal?: AbortSignal,
+  options: CodexStreamReadOptions = {},
+): AsyncGenerator<CodexSseEvent> {
   const reader = response.body?.getReader()
   if (!reader) return
   const readerCanceller = createReaderCanceller(reader, signal)
 
   const decoder = new TextDecoder()
   let buffer = ''
-  const STREAM_IDLE_TIMEOUT_MS = 120_000 // 2 minutes without data
+  const streamIdleTimeoutMs = options.idleTimeoutMs ?? STREAM_IDLE_TIMEOUT_MS
-  let lastDataTime = Date.now()
+  let lastDataTime = performance.now()
-  let streamComplete = false
+  let lastParsedFrameTime = lastDataTime
+  let transportComplete = false
+  let protocolComplete = false
+  let doneMarkerObserved = false
+  let rawByteCount = 0
+  let sawFirstRawByte = false
+  let parsedFrameCount = 0
+  let controlFrameCount = 0
+  let ignoredFrameCount = 0
+  let streamCausalEventId: string | undefined
+
+  traceInterruptionEvent('codex_stream.read_started', {
+    subsystem: 'codex_stream',
+    transport: 'codex_responses',
+  })
 
   /**
    * Read from the stream with an idle timeout. Respects the caller's
    * AbortSignal — clears the idle timer on abort so the AbortError
    * surfaces cleanly instead of a spurious idle timeout.
    */
-  async function readWithTimeout(): Promise<Bun.ReadableStreamDefaultReadResult<Uint8Array<ArrayBuffer>>> {
+  async function readWithTimeout() {
-    return new Promise((resolve, reject) => {
+    return readWithIdleTimeout(reader!, streamIdleTimeoutMs, {
-      let settled = false
+      signal,
-      let timeoutId: ReturnType<typeof setTimeout> | undefined = setTimeout(() => {
+      cancelReader: readerCanceller.cancel,
-        const elapsed = Math.round((Date.now() - lastDataTime) / 1000)
+      createTimeoutError: () => {
-        cancelAndReject(new Error(
+        const elapsed = Math.round((performance.now() - lastDataTime) / 1000)
-          `Codex SSE stream idle for ${elapsed}s (limit: ${STREAM_IDLE_TIMEOUT_MS / 1000}s). Connection likely dropped.`,
+        return new Error(
-        ))
+          `Codex SSE stream idle for ${elapsed}s (limit: ${streamIdleTimeoutMs / 1000}s). Connection likely dropped.`,
-      }, STREAM_IDLE_TIMEOUT_MS)
-
-      const cleanup = () => {
-        if (timeoutId !== undefined) {
-          clearTimeout(timeoutId)
-          timeoutId = undefined
-        }
-        signal?.removeEventListener('abort', onAbort)
-      }
-      const finishResolve = (
-        value: Bun.ReadableStreamDefaultReadResult<Uint8Array<ArrayBuffer>>,
-      ) => {
-        if (settled) return
-        settled = true
-        cleanup()
-        if (value.value) lastDataTime = Date.now()
-        resolve(value)
-      }
-      const finishReject = (error: unknown) => {
-        if (settled) return
-        settled = true
-        cleanup()
-        reject(error)
-      }
-      const cancelAndReject = (error: unknown) => {
-        readerCanceller.cancel(error)
-        finishReject(error)
-      }
-      const onAbort = () => cancelAndReject(createStreamAbortError())
-
-      signal?.addEventListener('abort', onAbort, { once: true })
-      if (signal?.aborted) {
-        onAbort()
-        return
-      }
-
-      // reader is guarded non-null above; hoisted function escapes TS narrowing.
-      reader!.read().then(
-        result => finishResolve(result),
-        err => finishReject(err),
         )
+      },
+      onTimeout: error => {
+        const now = performance.now()
+        streamCausalEventId = traceInterruptionEvent('codex_stream.idle_timeout', {
+          subsystem: 'codex_stream',
+          transport: 'codex_responses',
+          sinceLastRawByteMs: now - lastDataTime,
+          sinceLastParsedFrameMs: now - lastParsedFrameTime,
+          rawByteCount,
+          parsedFrameCount,
+          controlFrameCount,
+          ignoredFrameCount,
+        })
+        if (streamCausalEventId) {
+          options.onCausalEventId?.(streamCausalEventId)
+        }
+        setInterruptionErrorCausalEventId(error, streamCausalEventId)
+        flushInterruptionTrace('codex_stream_idle_timeout')
+      },
     })
   }
 
   try {
-    while (true) {
+    streamLoop: while (true) {
       const { done, value } = await readWithTimeout()
       if (done) {
-        streamComplete = true
+        transportComplete = true
+        traceInterruptionEvent('codex_stream.eof', {
+          subsystem: 'codex_stream',
+          transport: 'codex_responses',
+          rawByteCount,
+          parsedFrameCount,
+          controlFrameCount,
+          ignoredFrameCount,
+        })
         break
       }
 
       throwIfStreamAborted(signal)
+      if (value && value.byteLength > 0) {
+        lastDataTime = performance.now()
+        rawByteCount += value.byteLength
+        if (!sawFirstRawByte) {
+          sawFirstRawByte = true
+          traceInterruptionEvent('codex_stream.first_raw_byte', {
+            subsystem: 'codex_stream',
+            transport: 'codex_responses',
+            rawByteCount,
+          })
+        }
+      }
       buffer += decoder.decode(value, { stream: true })
       const chunks = buffer.split('\n\n')
       buffer = chunks.pop() ?? ''
@@ -797,33 +798,132 @@ async function* readSseEvents(response: Response, signal?: AbortSignal): AsyncGe
           .filter(Boolean)
         if (lines.length === 0) continue
 
+        if (lines.every(line => line.startsWith(':'))) {
+          controlFrameCount++
+          continue
+        }
+
         const eventLine = lines.find(line => line.startsWith('event: '))
         const dataLines = lines.filter(line => line.startsWith('data: '))
-        if (!eventLine || dataLines.length === 0) continue
+        if (dataLines.length === 0) {
+          controlFrameCount++
+          continue
+        }
 
-        const event = eventLine.slice(7).trim()
         const rawData = dataLines.map(line => line.slice(6)).join('\n')
-        if (rawData === '[DONE]') continue
+        if (rawData === '[DONE]') {
+          doneMarkerObserved = true
+          controlFrameCount++
+          traceInterruptionEvent('codex_stream.control_frame', {
+            subsystem: 'codex_stream',
+            transport: 'codex_responses',
+            phase: 'done_marker',
+            rawByteCount,
+            parsedFrameCount,
+            controlFrameCount,
+            ignoredFrameCount,
+          })
+          continue
+        }
 
         let data: Record<string, any>
         try {
           const parsed = JSON.parse(rawData)
-          if (!parsed || typeof parsed !== 'object') continue
+          if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
+            ignoredFrameCount++
+            continue
+          }
           data = parsed as Record<string, any>
         } catch {
+          ignoredFrameCount++
+          continue
+        }
+
+        const event = eventLine?.slice(7).trim() ??
+          (typeof data.type === 'string' ? data.type : undefined)
+        if (!event) {
+          controlFrameCount++
           continue
         }
 
         throwIfStreamAborted(signal)
+        parsedFrameCount++
+        lastParsedFrameTime = performance.now()
+        if (parsedFrameCount === 1) {
+          traceInterruptionEvent('codex_stream.first_parsed_frame', {
+            subsystem: 'codex_stream',
+            transport: 'codex_responses',
+            rawByteCount,
+            parsedFrameCount,
+            controlFrameCount,
+            ignoredFrameCount,
+          })
+        }
+        const isTerminalEvent =
+          event === 'response.completed' ||
+          event === 'response.incomplete' ||
+          event === 'response.failed'
+        if (isTerminalEvent) {
+          protocolComplete = true
+          traceInterruptionEvent('codex_stream.protocol_terminal', {
+            subsystem: 'codex_stream',
+            transport: 'codex_responses',
+            phase: event,
+            rawByteCount,
+            parsedFrameCount,
+            controlFrameCount,
+            ignoredFrameCount,
+          })
+        }
         yield { event, data }
+        if (isTerminalEvent) break streamLoop
+      }
+      if (doneMarkerObserved) {
+        protocolComplete = true
+        break
       }
     }
+  } catch (error) {
+    traceInterruptionEvent('codex_stream.error', {
+      subsystem: 'codex_stream',
+      transport: 'codex_responses',
+      outcome: signal?.aborted ? 'root_aborted' : 'external_error',
+      reason: signal?.reason,
+      causalEventId:
+        (signal && getInterruptionSignalAbortEventId(signal)) ??
+        streamCausalEventId,
+      error,
+      rawByteCount,
+      parsedFrameCount,
+      controlFrameCount,
+      ignoredFrameCount,
+    })
+    flushInterruptionTrace('codex_stream_error')
+    throw error
   } finally {
-    if (!streamComplete || signal?.aborted) {
+    const readerWasInterrupted =
-      readerCanceller.cancel(createStreamAbortError())
+      (!transportComplete && !protocolComplete) || signal?.aborted
+    if (readerWasInterrupted) {
+      const causalEventId =
+        (signal && getInterruptionSignalAbortEventId(signal)) ??
+        streamCausalEventId
+      traceInterruptionEvent('codex_stream.cancelled', {
+        subsystem: 'codex_stream',
+        transport: 'codex_responses',
+        reason: signal?.reason,
+        causalEventId,
+        rawByteCount,
+        parsedFrameCount,
+        controlFrameCount,
+        ignoredFrameCount,
+      })
     }
+    if (!transportComplete) readerCanceller.cancel(createStreamAbortError())
     readerCanceller.cleanup()
     reader.releaseLock()
+    if (readerWasInterrupted) {
+      flushInterruptionTrace('codex_stream_reader_closed')
+    }
   }
 }
 
@@ -882,10 +982,11 @@ export async function collectCodexCompletedResponse(
   return completedResponse
 }
 
-export async function* codexStreamToAnthropic(
+async function* codexStreamToAnthropicWithReadOptions(
   response: Response,
   model: string,
   signal?: AbortSignal,
+  readOptions: CodexStreamReadOptions = {},
 ): AsyncGenerator<AnthropicStreamEvent> {
   const messageId = makeMessageId()
   const toolBlocksByItemId = new Map<
@@ -898,6 +999,10 @@ export async function* codexStreamToAnthropic(
   let sawToolUse = false
   let finalResponse: Record<string, any> | undefined
   let streamComplete = false
+  let providerTerminalObserved = false
+  let converterFailed = false
+  let streamCausalEventId: string | undefined
+  let ignoredParsedFrameCount = 0
   const cancelResponseBody = () => {
     void response.body?.cancel(createStreamAbortError()).catch(() => {})
   }
@@ -953,7 +1058,13 @@ export async function* codexStreamToAnthropic(
       },
     }
 
-    for await (const event of readSseEvents(response, signal)) {
+    for await (const event of readSseEvents(response, signal, {
+      ...readOptions,
+      onCausalEventId: eventId => {
+        streamCausalEventId = eventId
+        readOptions.onCausalEventId?.(eventId)
+      },
+    })) {
       throwIfStreamAborted(signal)
       const payload = event.data
 
@@ -1113,15 +1224,26 @@ export async function* codexStreamToAnthropic(
         event.event === 'response.completed' ||
         event.event === 'response.incomplete'
       ) {
+        providerTerminalObserved = true
         finalResponse = payload.response
         break
       }
 
       if (event.event === 'response.failed') {
+        providerTerminalObserved = true
         const msg = payload?.response?.error?.message ??
           payload?.error?.message ?? 'Codex response failed'
         throw APIError.generate(500, undefined, msg, new Headers())
       }
+
+      ignoredParsedFrameCount++
+      if (ignoredParsedFrameCount === 1) {
+        traceInterruptionEvent('codex_stream.first_parsed_frame_ignored', {
+          subsystem: 'codex_stream',
+          transport: 'codex_responses',
+          ignoredParsedFrameCount,
+        })
+      }
     }
 
     throwIfStreamAborted(signal)
@@ -1151,16 +1273,60 @@ export async function* codexStreamToAnthropic(
       ),
     }
     throwIfStreamAborted(signal)
-    yield { type: 'message_stop' }
     streamComplete = true
+    yield { type: 'message_stop' }
+  } catch (error) {
+    converterFailed = true
+    throw error
   } finally {
-    if (!streamComplete || signal?.aborted) {
+    const terminalComplete = providerTerminalObserved && !converterFailed
+    traceInterruptionEvent('codex_stream.converter_closed', {
+      subsystem: 'codex_stream',
+      transport: 'codex_responses',
+      outcome: signal?.aborted
+        ? 'root_aborted'
+        : converterFailed
+          ? 'failed'
+          : streamComplete || terminalComplete
+            ? 'complete'
+            : 'incomplete',
+      reason: signal?.reason,
+      causalEventId:
+        (signal && getInterruptionSignalAbortEventId(signal)) ??
+        streamCausalEventId,
+      ignoredParsedFrameCount,
+    })
+    if ((!streamComplete && !terminalComplete) || signal?.aborted) {
       cancelResponseBody()
+      flushInterruptionTrace('codex_stream_converter_closed')
     }
     signal?.removeEventListener('abort', cancelResponseBody)
   }
 }
 
+export function codexStreamToAnthropic(
+  response: Response,
+  model: string,
+  signal?: AbortSignal,
+): AsyncGenerator<AnthropicStreamEvent> {
+  return codexStreamToAnthropicWithReadOptions(response, model, signal)
+}
+
+/** Deterministic reader-deadline seam for interruption regressions only. */
+export function __codexStreamToAnthropicForTests(
+  response: Response,
+  model: string,
+  signal: AbortSignal | undefined,
+  readOptions: CodexStreamReadOptions,
+): AsyncGenerator<AnthropicStreamEvent> {
+  return codexStreamToAnthropicWithReadOptions(
+    response,
+    model,
+    signal,
+    readOptions,
+  )
+}
+
 export function convertCodexResponseToAnthropicMessage(
   data: Record<string, any>,
   model: string,

src/services/api/openaiShim.test.ts

@@ -6,6 +6,10 @@ import { asMockFetch } from '../../test/typedMocks.js'
 import { _clearRegistryForTesting, ensureIntegrationsLoaded, registerGateway } from '../../integrations/index.ts'
 import { applyProviderFlag } from '../../utils/providerFlag.ts'
 import { applyProviderProfileToProcessEnv } from '../../utils/providerProfiles.ts'
+import {
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../../utils/interruptionTrace.js'
 import {
   getAssistantMessageFromError,
   OPENCODE_GO_FREE_LIMIT_ERROR_MESSAGE,
@@ -4751,6 +4755,49 @@ test('caller abort winning the timeout catch race prevents a retry', async () =>
   expect(fetchCalls).toBe(1)
 })
 
+test('interruption tracing preserves the native AbortSignal.any request path', async () => {
+  const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+  const originalAbortSignalAny = Object.getOwnPropertyDescriptor(
+    AbortSignal,
+    'any',
+  )
+  const nativeAny = AbortSignal.any.bind(AbortSignal)
+  let nativeAnyCalls = 0
+  Object.defineProperty(AbortSignal, 'any', {
+    configurable: true,
+    value: (signals: AbortSignal[]) => {
+      nativeAnyCalls++
+      return nativeAny(signals)
+    },
+  })
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  globalThis.fetch = asMockFetch(
+    mock(async () => makeChatCompletionResponse('gpt-4o-mini')),
+  )
+
+  try {
+    const client = createOpenAIShimClient({}) as OpenAIShimClient
+    await client.beta.messages.create(
+      {
+        model: 'gpt-4o-mini',
+        messages: [{ role: 'user', content: 'hello' }],
+        max_tokens: 64,
+        stream: false,
+      },
+      { signal: new AbortController().signal },
+    )
+    expect(nativeAnyCalls).toBe(1)
+  } finally {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    if (originalAbortSignalAny) {
+      Object.defineProperty(AbortSignal, 'any', originalAbortSignalAny)
+    }
+  }
+})
+
 test('manual signal fallback preserves caller cancellation after headers arrive', async () => {
   process.env.API_TIMEOUT_MS = '200'
   const fetchSignals: AbortSignal[] = []

src/services/api/openaiShim/clientDispatch.test.ts

@@ -1,4 +1,13 @@
 import { expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../../../utils/interruptionTrace.js'
 import type { AnthropicStreamEvent, ShimCreateParams } from '../codexShim.js'
 import {
   createShimRequest,
@@ -107,6 +116,47 @@ test('OpenAIShimStream combines parent and controller cancellation', async () =>
   expect(receivedSignal?.aborted).toBe(true)
 })
 
+test('OpenAIShimStream records its parent signal relationship', async () => {
+  await acquireSharedMutationLock('openaiShim-clientDispatch-parent-trace')
+  const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  __resetInterruptionTraceForTests()
+  const parent = new AbortController()
+  let stream: OpenAIShimStream | undefined
+  try {
+    stream = new OpenAIShimStream(async function* () {
+      yield { type: 'unused' }
+    }, parent.signal)
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const parentRegistration = trace.find(
+      entry =>
+        entry.event === 'signal.registered' &&
+        entry.controllerRole === 'combined-parent',
+    )
+    const streamRegistration = trace.find(
+      entry =>
+        entry.event === 'controller.registered' &&
+        entry.controllerRole === 'stream-controller',
+    )
+    expect(parentRegistration).toBeDefined()
+    expect(streamRegistration).toBeDefined()
+    if (!parentRegistration?.controllerId || !streamRegistration) {
+      throw new Error('missing interruption controller registration')
+    }
+    expect(streamRegistration.parentControllerIds).toEqual([
+      parentRegistration.controllerId,
+    ])
+  } finally {
+    stream?.controller.abort('test-cleanup')
+    parent.abort('test-cleanup')
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    releaseSharedMutationLock()
+  }
+})
+
 test('OpenAIShimStream cancels the response before iteration starts', () => {
   let cancellations = 0
   const stream = new OpenAIShimStream(
@@ -123,12 +173,61 @@ test('OpenAIShimStream cancels the response before iteration starts', () => {
 })
 
 test('OpenAIShimStream aborts its controller when a consumer returns early', async () => {
+  await acquireSharedMutationLock('openaiShim-clientDispatch-closure-trace')
+  const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  __resetInterruptionTraceForTests()
   const stream = new OpenAIShimStream(async function* () {
     yield { type: 'first' }
     yield { type: 'second' }
   })
+  try {
     for await (const _event of stream) break
     expect(stream.controller.signal.aborted).toBe(true)
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'abort.requested',
+      ),
+    ).toMatchObject({ source: 'iterator_closed' })
+  } finally {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    releaseSharedMutationLock()
+  }
+})
+
+test('OpenAIShimStream does not relabel a provider exception as consumer closure', async () => {
+  await acquireSharedMutationLock('openaiShim-clientDispatch-failure-trace')
+  const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  __resetInterruptionTraceForTests()
+  const stream = new OpenAIShimStream(async function* () {
+    yield { type: 'message_start' }
+    throw new Error('provider generator failed')
+  })
+
+  try {
+    const iterator = stream[Symbol.asyncIterator]()
+    expect((await iterator.next()).done).toBe(false)
+    await expect(iterator.next()).rejects.toThrow('provider generator failed')
+    expect(stream.controller.signal.aborted).toBe(false)
+    expect(
+      __getInterruptionTraceSnapshotForTests().some(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'iterator_closed',
+      ),
+    ).toBe(false)
+  } finally {
+    stream.controller.abort('test-cleanup')
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    releaseSharedMutationLock()
+  }
 })
 
 test.each([

src/services/api/openaiShim/clientDispatch.ts

@@ -1,5 +1,10 @@
 import { APIError } from '@anthropic-ai/sdk'
 import { createCombinedAbortSignal } from '../../../utils/combinedAbortSignal.js'
+import {
+  registerInterruptionController,
+  registerInterruptionSignal,
+  requestAbort,
+} from '../../../utils/interruptionTrace.js'
 import type { AnthropicStreamEvent, ShimCreateParams } from '../codexShim.js'
 import {
   isLikelyOllamaEndpoint,
@@ -90,6 +95,17 @@ export class OpenAIShimStream implements AsyncIterable<AnthropicStreamEvent> {
   ) {
     this.makeGenerator = makeGenerator
     this.parentSignal = parentSignal
+    const parentId = parentSignal
+      ? registerInterruptionSignal(parentSignal, {
+          subsystem: 'openai_shim_dispatch',
+          controllerRole: 'combined-parent',
+        })
+      : undefined
+    registerInterruptionController(this.controller, {
+      subsystem: 'openai_shim_dispatch',
+      controllerRole: 'stream-controller',
+      ...(parentId && { parentControllerIds: [parentId] }),
+    })
 
     if (cancelBeforeIteration) {
       let cleaned = false
@@ -129,6 +145,10 @@ export class OpenAIShimStream implements AsyncIterable<AnthropicStreamEvent> {
 
     const combined = createCombinedAbortSignal(this.parentSignal, {
       signalB: this.controller.signal,
+      trace: {
+        subsystem: 'openai_shim_dispatch',
+        controllerRole: 'stream-combined',
+      },
     })
     this.cleanupCombinedSignal = combined.cleanup
     this.generator = this.makeGenerator(combined.signal)
@@ -138,12 +158,20 @@ export class OpenAIShimStream implements AsyncIterable<AnthropicStreamEvent> {
   async *[Symbol.asyncIterator](): AsyncGenerator<AnthropicStreamEvent> {
     const generator = this.getGenerator()
     let completed = false
+    let failed = false
     try {
       yield* generator
       completed = true
+    } catch (error) {
+      failed = true
+      throw error
     } finally {
-      if (!completed && !this.controller.signal.aborted) {
+      if (!completed && !failed && !this.controller.signal.aborted) {
-        this.controller.abort()
+        requestAbort(this.controller, undefined, {
+          source: 'iterator_closed',
+          subsystem: 'openai_shim_dispatch',
+          controllerRole: 'stream-controller',
+        })
       }
       this.cleanupCombinedSignal?.()
       this.cleanupCombinedSignal = undefined

src/services/api/openaiShim/geminiStreamConversion.test.ts

@@ -1,5 +1,6 @@
 import { expect, test } from 'bun:test'
 import {
+  createProviderStreamTrace,
   createReaderCanceller,
   createStreamAbortError,
   readWithIdleTimeout,
@@ -8,6 +9,7 @@ import {
 import { geminiSseToAnthropic } from './geminiStreamConversion.js'
 
 const dependencies = {
+  createProviderStreamTrace,
   createReaderCanceller,
   createStreamAbortError,
   getStreamIdleTimeoutMs: () => 1_000,

src/services/api/openaiShim/geminiStreamConversion.ts

@@ -1,6 +1,7 @@
 import { buildAnthropicUsageFromRawUsage } from '../cacheMetrics.js'
 import type { AnthropicStreamEvent, AnthropicUsage } from '../codexShim.js'
 import { logForDebugging } from '../../../utils/debug.js'
+import type { createProviderStreamTrace } from './streamControl.js'
 
 type ReaderCanceller = {
   cancel(error?: unknown): void
@@ -16,6 +17,7 @@ export type GeminiStreamDependencies = {
     reader: ReadableStreamDefaultReader<Uint8Array>,
     signal?: AbortSignal,
   ): ReaderCanceller
+  createProviderStreamTrace: typeof createProviderStreamTrace
   createStreamAbortError(): DOMException
   getStreamIdleTimeoutMs(): number
   makeMessageId(): string
@@ -25,7 +27,7 @@ export type GeminiStreamDependencies = {
     options?: {
       signal?: AbortSignal
       cancelReader?: (error?: unknown) => void
-      onTimeout?: () => void
+      onTimeout?: (error: unknown) => void
     },
   ): Promise<StreamReadResult>
   throwIfStreamAborted(signal?: AbortSignal): void
@@ -39,6 +41,7 @@ export async function* geminiSseToAnthropic(
 ): AsyncGenerator<AnthropicStreamEvent> {
   const {
     createReaderCanceller,
+    createProviderStreamTrace,
     createStreamAbortError,
     getStreamIdleTimeoutMs,
     makeMessageId,
@@ -59,8 +62,11 @@ export async function* geminiSseToAnthropic(
   let usage: Partial<AnthropicUsage> | undefined
   let finishReason: string | undefined
   const streamIdleTimeoutMs = getStreamIdleTimeoutMs()
-  let lastDataTime = Date.now()
+  let lastDataTime = performance.now()
   let streamComplete = false
+  let protocolComplete = false
+  let readerFailed = false
+  const streamTrace = createProviderStreamTrace('gemini_sse')
 
   const emitMessageStart = async function* () {
     if (hasEmittedStart) return
@@ -98,20 +104,23 @@ export async function* geminiSseToAnthropic(
         {
           signal,
           cancelReader: readerCanceller.cancel,
-          onTimeout: () => {
+          onTimeout: error => {
-            const elapsed = Math.round((Date.now() - lastDataTime) / 1000)
+            const elapsed = Math.round((performance.now() - lastDataTime) / 1000)
             logForDebugging(
               `Gemini SSE stream idle for ${elapsed}s (limit: ${streamIdleTimeoutMs / 1000}s). Connection likely dropped.`,
               { level: 'error' },
             )
+            streamTrace.recordIdleTimeout(error)
           },
         },
       )
       if (done) {
         streamComplete = true
+        streamTrace.recordEof()
         break
       }
-      if (value) lastDataTime = Date.now()
+      if (value) lastDataTime = performance.now()
+      streamTrace.recordRaw(value)
 
       throwIfStreamAborted(signal)
       buffer += decoder.decode(value, { stream: true })
@@ -122,10 +131,15 @@ export async function* geminiSseToAnthropic(
         throwIfStreamAborted(signal)
         const lines = chunk.split('\n').map(line => line.trim()).filter(Boolean)
         const dataLines = lines.filter(line => line.startsWith('data: '))
-        if (dataLines.length === 0) continue
+        if (dataLines.length === 0) {
+          streamTrace.recordControl()
+          continue
+        }
 
         const rawData = dataLines.map(line => line.slice(6)).join('\n')
         if (rawData === '[DONE]') {
+          streamTrace.recordControl()
+          protocolComplete = true
           yield* emitMessageStart()
           if (hasEmittedTextStart || hasEmittedCurrentTool) {
             throwIfStreamAborted(signal)
@@ -149,8 +163,15 @@ export async function* geminiSseToAnthropic(
 
         let parsed: Record<string, unknown>
         try {
-          parsed = JSON.parse(rawData) as Record<string, unknown>
+          const value: unknown = JSON.parse(rawData)
+          if (!value || typeof value !== 'object' || Array.isArray(value)) {
+            streamTrace.recordIgnored()
+          } else {
+            streamTrace.recordParsed()
+          }
+          parsed = value as Record<string, unknown>
         } catch {
+          streamTrace.recordIgnored()
           continue
         }
 
@@ -173,6 +194,7 @@ export async function* geminiSseToAnthropic(
         const candidate = candidates[0]
         if (typeof candidate.finishReason === 'string') {
           finishReason = candidate.finishReason
+          protocolComplete = true
         }
 
         const content = candidate.content as
@@ -267,8 +289,22 @@ export async function* geminiSseToAnthropic(
     }
     throwIfStreamAborted(signal)
     yield { type: 'message_stop' }
-    streamComplete = true
+  } catch (error) {
+    readerFailed = true
+    throw error
   } finally {
+    streamTrace.recordClosed(
+      signal?.aborted
+        ? 'root_aborted'
+        : readerFailed
+          ? 'failed'
+          : protocolComplete
+            ? 'complete'
+          : streamComplete
+            ? 'eof_without_terminal'
+            : 'incomplete',
+      signal,
+    )
     if (!streamComplete || signal?.aborted) {
       readerCanceller.cancel(createStreamAbortError())
     }

src/services/api/openaiShim/providerStreamInterruptionTrace.test.ts

@@ -0,0 +1,366 @@
+import { afterAll, afterEach, beforeAll, expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../../../utils/interruptionTrace.js'
+import type { AnthropicStreamEvent } from '../codexShim.js'
+import {
+  anthropicSsePassthrough,
+  geminiSseToAnthropic,
+  openaiStreamToAnthropic,
+} from './responseAdapters.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+const originalIdleTimeout = process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS
+
+beforeAll(async () => {
+  await acquireSharedMutationLock('providerStreamInterruptionTrace.test.ts')
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+})
+
+afterEach(() => {
+  if (originalIdleTimeout === undefined) {
+    delete process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS
+  } else {
+    process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = originalIdleTimeout
+  }
+})
+
+afterAll(() => {
+  __resetInterruptionTraceForTests()
+  if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+  else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+  if (originalIdleTimeout === undefined) {
+    delete process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS
+  } else {
+    process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = originalIdleTimeout
+  }
+  releaseSharedMutationLock()
+})
+
+function responseFromText(text: string): Response {
+  const encoder = new TextEncoder()
+  return new Response(
+    new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(encoder.encode(text))
+        controller.close()
+      },
+    }),
+    { headers: { 'content-type': 'text/event-stream' } },
+  )
+}
+
+function openResponseFromText(
+  text: string,
+  onCancel?: () => void,
+): Response {
+  const encoder = new TextEncoder()
+  return new Response(
+    new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(encoder.encode(text))
+      },
+      cancel() {
+        onCancel?.()
+      },
+    }),
+    { headers: { 'content-type': 'text/event-stream' } },
+  )
+}
+
+async function collect(
+  stream: AsyncIterable<AnthropicStreamEvent>,
+): Promise<AnthropicStreamEvent[]> {
+  const events: AnthropicStreamEvent[] = []
+  for await (const event of stream) events.push(event)
+  return events
+}
+
+test('all non-Codex readers distinguish raw, parsed, control, and ignored frames', async () => {
+  const cases = [
+    {
+      transport: 'openai_chat_completions',
+      text: [
+        ': keepalive',
+        'data: not-json',
+        'data: []',
+        'data: {"choices":[{"delta":{"content":"hello"},"finish_reason":"stop"}]}',
+        'data: [DONE]',
+        '',
+      ].join('\n'),
+      expected: { parsed: 1, control: 2, ignored: 2 },
+      stream: (text: string) =>
+        openaiStreamToAnthropic(responseFromText(text), 'test-model'),
+    },
+    {
+      transport: 'gemini_sse',
+      text: [
+        ': keepalive',
+        '',
+        'data: not-json',
+        '',
+        'data: []',
+        '',
+        'data: {"candidates":[{"content":{"parts":[{"text":"hello"}]},"finishReason":"STOP"}]}',
+        '',
+        'data: [DONE]',
+        '',
+        '',
+      ].join('\n'),
+      expected: { parsed: 1, control: 2, ignored: 2 },
+      stream: (text: string) =>
+        geminiSseToAnthropic(responseFromText(text), 'gemini-test'),
+    },
+    {
+      transport: 'anthropic_messages',
+      text: [
+        ': keepalive',
+        '',
+        'data: not-json',
+        '',
+        'data: {}',
+        '',
+        'data: {"type":"message_stop"}',
+        '',
+        'data: [DONE]',
+        '',
+        '',
+      ].join('\n'),
+      expected: { parsed: 1, control: 2, ignored: 2 },
+      stream: (text: string) =>
+        anthropicSsePassthrough(responseFromText(text), 'claude-test'),
+    },
+  ]
+
+  for (const scenario of cases) {
+    __resetInterruptionTraceForTests()
+    await collect(scenario.stream(scenario.text))
+
+    const closed = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'provider_stream.reader_closed' &&
+        entry.transport === scenario.transport,
+    )
+    expect(closed).toMatchObject({
+      outcome: 'complete',
+      rawByteCount: new TextEncoder().encode(scenario.text).byteLength,
+      parsedFrameCount: scenario.expected.parsed,
+      controlFrameCount: scenario.expected.control,
+      ignoredFrameCount: scenario.expected.ignored,
+    })
+  }
+})
+
+for (const traceEnabled of [false, true]) {
+  test(`OpenAI-compatible and Gemini null payloads fail with tracing ${traceEnabled ? 'enabled' : 'disabled'}`, async () => {
+    const previousTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    try {
+      if (traceEnabled) process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+      else delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+      const cases = [
+        {
+          transport: 'openai_chat_completions',
+          stream: () =>
+            openaiStreamToAnthropic(
+              responseFromText('data: null\n\ndata: [DONE]\n\n'),
+              'test-model',
+            ),
+        },
+        {
+          transport: 'gemini_sse',
+          stream: () =>
+            geminiSseToAnthropic(
+              responseFromText('data: null\n\ndata: [DONE]\n\n'),
+              'gemini-test',
+            ),
+        },
+      ]
+
+      for (const scenario of cases) {
+        __resetInterruptionTraceForTests()
+        await expect(collect(scenario.stream())).rejects.toBeInstanceOf(TypeError)
+        const snapshot = __getInterruptionTraceSnapshotForTests()
+        if (!traceEnabled) {
+          expect(snapshot).toEqual([])
+          continue
+        }
+        expect(
+          snapshot.find(
+            entry =>
+              entry.event === 'provider_stream.reader_closed' &&
+              entry.transport === scenario.transport,
+          ),
+        ).toMatchObject({
+          outcome: 'failed',
+          ignoredFrameCount: 1,
+        })
+      }
+    } finally {
+      __resetInterruptionTraceForTests()
+      if (previousTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = previousTrace
+    }
+  })
+}
+
+test('Anthropic terminal consumer closure cancels an open response body', async () => {
+  __resetInterruptionTraceForTests()
+  let cancellations = 0
+  const iterator = anthropicSsePassthrough(
+    openResponseFromText(
+      'data: {"type":"message_stop"}\n\n',
+      () => {
+        cancellations++
+      },
+    ),
+    'claude-test',
+  )[Symbol.asyncIterator]()
+
+  expect((await iterator.next()).value?.type).toBe('message_stop')
+  await iterator.return?.(undefined)
+  expect(cancellations).toBe(1)
+})
+
+test('all non-Codex readers report a failure after terminal evidence then timeout', async () => {
+  process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = '20'
+  const cases = [
+    {
+      transport: 'openai_chat_completions',
+      stream: () =>
+        openaiStreamToAnthropic(
+          openResponseFromText(
+            'data: {"choices":[{"delta":{"content":"hello"},"finish_reason":"stop"}]}\n',
+          ),
+          'test-model',
+        ),
+    },
+    {
+      transport: 'gemini_sse',
+      stream: () =>
+        geminiSseToAnthropic(
+          openResponseFromText(
+            'data: {"candidates":[{"content":{"parts":[{"text":"hello"}]},"finishReason":"STOP"}]}\n\n',
+          ),
+          'gemini-test',
+        ),
+    },
+    {
+      transport: 'anthropic_messages',
+      stream: () =>
+        anthropicSsePassthrough(
+          openResponseFromText('data: {"type":"message_stop"}\n\n'),
+          'claude-test',
+        ),
+    },
+  ]
+
+  for (const scenario of cases) {
+    __resetInterruptionTraceForTests()
+    await expect(collect(scenario.stream())).rejects.toBeDefined()
+    const closed = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'provider_stream.reader_closed' &&
+        entry.transport === scenario.transport,
+    )
+    expect(closed?.outcome).toBe('failed')
+  }
+})
+
+test('all non-Codex readers distinguish transport EOF from protocol completion', async () => {
+  const cases = [
+    {
+      transport: 'openai_chat_completions',
+      stream: () =>
+        openaiStreamToAnthropic(
+          responseFromText(
+            'data: {"choices":[{"delta":{"content":"hello"},"finish_reason":null}]}\n',
+          ),
+          'test-model',
+        ),
+    },
+    {
+      transport: 'gemini_sse',
+      stream: () =>
+        geminiSseToAnthropic(
+          responseFromText(
+            'data: {"candidates":[{"content":{"parts":[{"text":"hello"}]}}]}\n\n',
+          ),
+          'gemini-test',
+        ),
+    },
+    {
+      transport: 'anthropic_messages',
+      stream: () =>
+        anthropicSsePassthrough(
+          responseFromText(
+            'data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"hello"}}\n\n',
+          ),
+          'claude-test',
+        ),
+    },
+  ]
+
+  for (const scenario of cases) {
+    __resetInterruptionTraceForTests()
+    await collect(scenario.stream())
+
+    const closed = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'provider_stream.reader_closed' &&
+        entry.transport === scenario.transport,
+    )
+    expect(closed?.outcome).toBe('eof_without_terminal')
+  }
+})
+
+test('all non-Codex reader idle errors carry the provider timeout causal event', async () => {
+  process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = '20'
+  const cases = [
+    {
+      transport: 'openai_chat_completions',
+      stream: (response: Response) =>
+        openaiStreamToAnthropic(response, 'test-model'),
+    },
+    {
+      transport: 'gemini_sse',
+      stream: (response: Response) =>
+        geminiSseToAnthropic(response, 'gemini-test'),
+    },
+    {
+      transport: 'anthropic_messages',
+      stream: (response: Response) =>
+        anthropicSsePassthrough(response, 'claude-test'),
+    },
+  ]
+
+  for (const scenario of cases) {
+    __resetInterruptionTraceForTests()
+    const response = new Response(new ReadableStream<Uint8Array>())
+    let caught: unknown
+    try {
+      await collect(scenario.stream(response))
+    } catch (error) {
+      caught = error
+    }
+
+    const idleTimeout = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'provider_stream.idle_timeout' &&
+        entry.transport === scenario.transport,
+    )
+    const readerClosed = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'provider_stream.reader_closed' &&
+        entry.transport === scenario.transport,
+    )
+    expect(caught).toBeDefined()
+    expect(idleTimeout).toBeDefined()
+    expect(readerClosed?.causalEventId).toBe(idleTimeout?.eventId)
+  }
+})

src/services/api/openaiShim/responseAdapters.ts

@@ -25,6 +25,7 @@ import { openaiStreamToAnthropic as convertOpenAIStream } from './streamConversi
 import { geminiSseToAnthropic as convertGeminiStream } from './geminiStreamConversion.js'
 import {
   anthropicSsePassthrough as parseAnthropicSsePassthrough,
+  createProviderStreamTrace,
   createReaderCanceller,
   createStreamAbortError,
   getStreamIdleTimeoutMs,
@@ -93,6 +94,7 @@ export async function* geminiSseToAnthropic(
   signal?: AbortSignal,
 ): AsyncGenerator<AnthropicStreamEvent> {
   yield* convertGeminiStream(response, model, signal, {
+    createProviderStreamTrace,
     createReaderCanceller,
     createStreamAbortError,
     getStreamIdleTimeoutMs,
@@ -135,6 +137,7 @@ export async function* openaiStreamToAnthropic(
         streamModel,
       ),
     couldBeRawToolCallsRequestedPrefix,
+    createProviderStreamTrace,
     createReaderCanceller,
     createStreamAbortError,
     findXmlToolCallOpener,

src/services/api/openaiShim/streamControl.test.ts

@@ -142,6 +142,28 @@ test('readWithIdleTimeout settles when a custom canceller throws synchronously',
   reader.releaseLock()
 })
 
+test('readWithIdleTimeout contains a throwing custom error factory', async () => {
+  const cancelReasons: unknown[] = []
+  const reader = new ReadableStream<Uint8Array>({
+    cancel(reason) {
+      cancelReasons.push(reason)
+    },
+  }).getReader()
+
+  await expect(
+    withDeadline(
+      readWithIdleTimeout(reader, 20, {
+        createTimeoutError: () => {
+          throw new Error('factory failed')
+        },
+      }),
+      'idle timeout did not reject within 500ms',
+    ),
+  ).rejects.toBeInstanceOf(StreamIdleTimeoutError)
+  expect(cancelReasons).toHaveLength(1)
+  expect(cancelReasons[0]).toBeInstanceOf(StreamIdleTimeoutError)
+})
+
 test('stream idle timeout parser validates and bounds overrides', () => {
   expect(getStreamIdleTimeoutMs()).toBe(90_000)
   process.env.CLAUDE_STREAM_IDLE_TIMEOUT_MS = '25'

src/services/api/openaiShim/streamControl.ts

@@ -1,3 +1,10 @@
+import {
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  setInterruptionErrorCausalEventId,
+  traceInterruptionEvent,
+} from '../../../utils/interruptionTrace.js'
+
 const DEFAULT_STREAM_IDLE_TIMEOUT_MS = 90_000
 const MAX_STREAM_IDLE_TIMEOUT_MS = 2_147_483_647
 
@@ -57,13 +64,79 @@ export function getStreamIdleTimeoutMs(): number {
     : DEFAULT_STREAM_IDLE_TIMEOUT_MS
 }
 
+export function createProviderStreamTrace(transport: string) {
+  let lastRawByteTime = performance.now()
+  let lastParsedFrameTime = lastRawByteTime
+  let rawByteCount = 0
+  let parsedFrameCount = 0
+  let controlFrameCount = 0
+  let ignoredFrameCount = 0
+  let causalEventId: string | undefined
+
+  const fields = () => ({
+    subsystem: 'provider_stream',
+    transport,
+    rawByteCount,
+    parsedFrameCount,
+    controlFrameCount,
+    ignoredFrameCount,
+  })
+
+  traceInterruptionEvent('provider_stream.read_started', fields())
+
+  return {
+    recordRaw(value: Uint8Array | undefined): void {
+      if (!value || value.byteLength === 0) return
+      lastRawByteTime = performance.now()
+      rawByteCount += value.byteLength
+      if (rawByteCount === value.byteLength) {
+        traceInterruptionEvent('provider_stream.first_raw_byte', fields())
+      }
+    },
+    recordParsed(): void {
+      lastParsedFrameTime = performance.now()
+      parsedFrameCount++
+    },
+    recordControl(): void {
+      controlFrameCount++
+    },
+    recordIgnored(): void {
+      ignoredFrameCount++
+    },
+    recordIdleTimeout(error: unknown): void {
+      const now = performance.now()
+      causalEventId = traceInterruptionEvent('provider_stream.idle_timeout', {
+        ...fields(),
+        sinceLastRawByteMs: now - lastRawByteTime,
+        sinceLastParsedFrameMs: now - lastParsedFrameTime,
+      })
+      setInterruptionErrorCausalEventId(error, causalEventId)
+      flushInterruptionTrace('provider_stream_idle_timeout')
+    },
+    recordEof(): void {
+      traceInterruptionEvent('provider_stream.eof', fields())
+    },
+    recordClosed(outcome: string, signal?: AbortSignal): void {
+      traceInterruptionEvent('provider_stream.reader_closed', {
+        ...fields(),
+        outcome,
+        reason: signal?.reason,
+        causalEventId:
+          (signal && getInterruptionSignalAbortEventId(signal)) ??
+          causalEventId,
+      })
+    },
+  }
+}
+
 export async function readWithIdleTimeout(
   reader: ReadableStreamDefaultReader<Uint8Array>,
   timeoutMs: number,
   options: {
     signal?: AbortSignal
     cancelReader?: (error?: unknown) => void
-    onTimeout?: () => void
+    onTimeout?: (error: unknown) => void
+    createTimeoutError?: () => unknown
   } = {},
 ): Promise<StreamReadResult> {
   const signal = options.signal
@@ -111,9 +184,15 @@ export async function readWithIdleTimeout(
     }
 
     timeoutId = setTimeout(() => {
-      const error = new StreamIdleTimeoutError(timeoutMs)
+      let error: unknown
       try {
-        options.onTimeout?.()
+        error = options.createTimeoutError?.()
+      } catch {
+        // Fall back to the standard timeout error.
+      }
+      error ??= new StreamIdleTimeoutError(timeoutMs)
+      try {
+        options.onTimeout?.(error)
       } catch {
         // Ignore diagnostic callback failures.
       }
@@ -140,27 +219,33 @@ export async function* anthropicSsePassthrough<T extends object>(
   const decoder = new TextDecoder()
   let buffer = ''
   const streamIdleTimeoutMs = getStreamIdleTimeoutMs()
-  let lastDataTime = Date.now()
+  let lastDataTime = performance.now()
   let streamComplete = false
+  let protocolComplete = false
+  let readerFailed = false
+  const streamTrace = createProviderStreamTrace('anthropic_messages')
 
   try {
     while (true) {
       const { done, value } = await readWithIdleTimeout(reader, streamIdleTimeoutMs, {
         signal,
         cancelReader: readerCanceller.cancel,
-        onTimeout: () => {
+        onTimeout: error => {
-          const elapsed = Math.round((Date.now() - lastDataTime) / 1000)
+          const elapsed = Math.round((performance.now() - lastDataTime) / 1000)
           logForDebugging(
             `Anthropic-compatible SSE stream idle for ${elapsed}s (limit: ${streamIdleTimeoutMs / 1000}s). Connection likely dropped.`,
             { level: 'error' },
           )
+          streamTrace.recordIdleTimeout(error)
         },
       })
       if (done) {
         streamComplete = true
+        streamTrace.recordEof()
         buffer += decoder.decode()
       } else {
-        if (value) lastDataTime = Date.now()
+        if (value) lastDataTime = performance.now()
+        streamTrace.recordRaw(value)
         throwIfStreamAborted(signal)
         buffer += decoder.decode(value, { stream: true })
       }
@@ -170,10 +255,14 @@ export async function* anthropicSsePassthrough<T extends object>(
         throwIfStreamAborted(signal)
         const lines = chunk.split(/\r\n|\n|\r/).map(line => line.trim()).filter(Boolean)
         const dataLines = lines.filter(line => line.startsWith('data:'))
-        if (dataLines.length === 0) continue
+        if (dataLines.length === 0) {
+          streamTrace.recordControl()
+          continue
+        }
         const rawData = dataLines.map(line => line.slice(5).replace(/^ /, '')).join('\n')
         if (rawData === '[DONE]') {
-          streamComplete = true
+          streamTrace.recordControl()
+          protocolComplete = true
           readerCanceller.cancel()
           return
         }
@@ -182,17 +271,41 @@ export async function* anthropicSsePassthrough<T extends object>(
           parsed = JSON.parse(rawData) as T
         } catch {
           // Ignore malformed frames and continue parsing later frames.
+          streamTrace.recordIgnored()
           continue
         }
         if (parsed && typeof parsed === 'object' && 'type' in parsed) {
+          streamTrace.recordParsed()
+          if ((parsed as { type?: unknown }).type === 'message_stop') {
+            protocolComplete = true
+          }
           throwIfStreamAborted(signal)
           yield parsed as Awaited<T>
+        } else {
+          streamTrace.recordIgnored()
         }
       }
       if (done) break
     }
+  } catch (error) {
+    readerFailed = true
+    throw error
   } finally {
-    if (!streamComplete || signal?.aborted) readerCanceller.cancel(createStreamAbortError())
+    streamTrace.recordClosed(
+      signal?.aborted
+        ? 'root_aborted'
+        : readerFailed
+          ? 'failed'
+          : protocolComplete
+            ? 'complete'
+          : streamComplete
+            ? 'eof_without_terminal'
+            : 'incomplete',
+      signal,
+    )
+    if (!streamComplete || signal?.aborted) {
+      readerCanceller.cancel(createStreamAbortError())
+    }
     readerCanceller.cleanup()
     reader.releaseLock()
   }

src/services/api/openaiShim/streamConversion.test.ts

@@ -9,6 +9,7 @@ import {
   geminiSseToAnthropic,
   type GeminiStreamDependencies,
 } from './geminiStreamConversion.js'
+import { createProviderStreamTrace } from './streamControl.js'
 
 function makeSseResponse(frames: unknown[]): Response {
   const encoder = new TextEncoder()
@@ -77,6 +78,7 @@ async function readWithSignal(
 }
 
 const commonControlDependencies: GeminiStreamDependencies = {
+  createProviderStreamTrace,
   createReaderCanceller,
   createStreamAbortError: () => new DOMException('Aborted', 'AbortError'),
   getStreamIdleTimeoutMs: () => 1_000,

src/services/api/openaiShim/streamConversion.ts

@@ -16,6 +16,7 @@ import {
   getStreamStats,
   processStreamChunk,
 } from '../../../utils/streamingOptimizer.js'
+import type { createProviderStreamTrace } from './streamControl.js'
 
 type ParsedRawToolCall = { id: string; name: string; argumentsJson: string }
 type ParsedTextToolCall = { id: string; name: string; arguments: unknown }
@@ -65,6 +66,7 @@ export type StreamConversionDependencies = {
     reader: ReadableStreamDefaultReader<Uint8Array>,
     signal?: AbortSignal,
   ): ReaderCanceller
+  createProviderStreamTrace: typeof createProviderStreamTrace
   createStreamAbortError(): DOMException
   findXmlToolCallOpener(text: string, allowHy3: boolean): number
   geminiThoughtSignatureFromExtraContent(extraContent: unknown): string | undefined
@@ -85,7 +87,7 @@ export type StreamConversionDependencies = {
     options?: {
       signal?: AbortSignal
       cancelReader?: (error?: unknown) => void
-      onTimeout?: () => void
+      onTimeout?: (error: unknown) => void
     },
   ): Promise<StreamReadResult>
   repairPossiblyTruncatedObjectJson(raw: string): string | null
@@ -116,6 +118,7 @@ export async function* openaiStreamToAnthropic(
     convertNonStreamingResponseToAnthropicMessage,
     couldBeRawToolCallsRequestedPrefix,
     createReaderCanceller,
+    createProviderStreamTrace,
     createStreamAbortError,
     findXmlToolCallOpener,
     geminiThoughtSignatureFromExtraContent,
@@ -154,6 +157,8 @@ export async function* openaiStreamToAnthropic(
   let lastStopReason: 'tool_use' | 'max_tokens' | 'end_turn' | null = null
   let hasEmittedFinalUsage = false
   let protocolComplete = false
+  let providerTerminalObserved = false
+  let readerFailed = false
   let hasProcessedFinishReason = false
   // Accumulated text for Ollama text-based tool call fallback parsing (#1053)
   let accumulatedText = ''
@@ -299,8 +304,9 @@ export async function* openaiStreamToAnthropic(
   const decoder = new TextDecoder()
   let buffer = ''
   const streamIdleTimeoutMs = getStreamIdleTimeoutMs()
-  let lastDataTime = Date.now()
+  let lastDataTime = performance.now()
   let streamComplete = false
+  const streamTrace = createProviderStreamTrace('openai_chat_completions')
 
   const closeActiveContentBlock = async function* () {
     if (!hasEmittedContentStart) return
@@ -463,19 +469,22 @@ export async function* openaiStreamToAnthropic(
       const { done, value } = await readWithIdleTimeout(reader, streamIdleTimeoutMs, {
         signal,
         cancelReader: readerCanceller.cancel,
-        onTimeout: () => {
+        onTimeout: error => {
-          const elapsed = Math.round((Date.now() - lastDataTime) / 1000)
+          const elapsed = Math.round((performance.now() - lastDataTime) / 1000)
           logForDebugging(
             `OpenAI-compatible SSE stream idle for ${elapsed}s (limit: ${streamIdleTimeoutMs / 1000}s). Connection likely dropped.`,
             { level: 'error' },
           )
+          streamTrace.recordIdleTimeout(error)
         },
       })
       if (done) {
         streamComplete = true
+        streamTrace.recordEof()
         break
       }
-      if (value) lastDataTime = Date.now()
+      if (value) lastDataTime = performance.now()
+      streamTrace.recordRaw(value)
 
       throwIfStreamAborted(signal)
       buffer += decoder.decode(value, { stream: true })
@@ -487,17 +496,32 @@ export async function* openaiStreamToAnthropic(
       const trimmed = line.trim()
       if (!trimmed) continue
       if (trimmed === 'data: [DONE]') {
+        streamTrace.recordControl()
         // `[DONE]` is protocol completion; do not wait for a transport EOF.
         // Leave streamComplete false so finally cancels an unread response body.
         protocolComplete = true
         break
       }
-      if (!trimmed.startsWith('data: ')) continue
+      if (!trimmed.startsWith('data: ')) {
+        if (trimmed.startsWith(':') || trimmed.startsWith('event:')) {
+          streamTrace.recordControl()
+        } else {
+          streamTrace.recordIgnored()
+        }
+        continue
+      }
 
       let chunk: OpenAIStreamChunk
       try {
-        chunk = JSON.parse(trimmed.slice(6))
+        const parsed: unknown = JSON.parse(trimmed.slice(6))
+        if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
+          streamTrace.recordIgnored()
+        } else {
+          streamTrace.recordParsed()
+        }
+        chunk = parsed as OpenAIStreamChunk
       } catch {
+        streamTrace.recordIgnored()
         continue
       }
 
@@ -752,6 +776,7 @@ export async function* openaiStreamToAnthropic(
         // Finish — guard ensures we only process finish_reason once even if
         // multiple chunks arrive with finish_reason set (some providers do this)
         if (choice.finish_reason && !hasProcessedFinishReason) {
+          providerTerminalObserved = true
           hasProcessedFinishReason = true
 
           // Close any open thinking block that wasn't closed by content transition
@@ -1083,7 +1108,22 @@ export async function* openaiStreamToAnthropic(
       if (protocolComplete) break
     }
     yield* finalizeIncompleteStream()
+  } catch (error) {
+    readerFailed = true
+    throw error
   } finally {
+    streamTrace.recordClosed(
+      signal?.aborted
+        ? 'root_aborted'
+        : readerFailed
+          ? 'failed'
+          : protocolComplete || providerTerminalObserved
+            ? 'complete'
+          : streamComplete
+            ? 'eof_without_terminal'
+            : 'incomplete',
+      signal,
+    )
     if (!streamComplete || signal?.aborted) {
       readerCanceller.cancel(createStreamAbortError())
     }

src/services/api/openaiShim/transport.ts

@@ -9,6 +9,16 @@ import {
   redactSecretSubstringsForDisplay,
 } from '../../../utils/providerSecrets.js'
 import { redactUrlForDisplay } from '../../../utils/redaction.js'
+import {
+  getInterruptionSignalAbortEventId,
+  getInterruptionSignalId,
+  registerInterruptionController,
+  registerInterruptionSignal,
+  requestAbort,
+  traceCombinedAbortSignal,
+  traceCombinedSignal,
+  traceInterruptionEvent,
+} from '../../../utils/interruptionTrace.js'
 import {
   buildOpenAICompatibilityErrorMessage,
   classifyOpenAINetworkFailure,
@@ -82,28 +92,69 @@ function combineRequestSignals(
   }
 
   if (typeof AbortSignal.any === 'function') {
+    const signal = AbortSignal.any([callerSignal, deadlineSignal])
+    traceCombinedAbortSignal(signal, [callerSignal, deadlineSignal], {
+      subsystem: 'openai_shim_transport',
+      controllerRole: 'request-combined',
+    })
     return {
-      signal: AbortSignal.any([callerSignal, deadlineSignal]),
+      signal,
       cleanupAfterHeaders: () => {},
       cleanup: () => {},
     }
   }
 
   const combined = new AbortController()
+  const callerId = registerInterruptionSignal(callerSignal, {
+    subsystem: 'openai_shim_transport',
+    controllerRole: 'request-caller',
+  })
+  const deadlineId = registerInterruptionSignal(deadlineSignal, {
+    subsystem: 'openai_shim_transport',
+    controllerRole: 'headers-deadline',
+  })
+  const parentControllerIds = [callerId, deadlineId].filter(
+    (id): id is string => id !== undefined,
+  )
+  traceCombinedSignal(combined, [callerSignal, deadlineSignal], {
+    subsystem: 'openai_shim_transport',
+    controllerRole: 'request-combined',
+  })
   const abortFromCaller = () => {
     deadlineSignal.removeEventListener('abort', abortFromDeadline)
-    combined.abort(callerSignal.reason)
+    requestAbort(combined, callerSignal.reason, {
+      source: 'request_caller',
+      subsystem: 'openai_shim_transport',
+      controllerRole: 'request-combined',
+      parentControllerIds,
+      winningParentControllerId: getInterruptionSignalId(callerSignal),
+      causalEventId: getInterruptionSignalAbortEventId(callerSignal),
+    })
   }
   const abortFromDeadline = () => {
     callerSignal.removeEventListener('abort', abortFromCaller)
-    combined.abort(deadlineSignal.reason)
+    requestAbort(combined, deadlineSignal.reason, {
+      source: 'headers_deadline',
+      subsystem: 'openai_shim_transport',
+      controllerRole: 'request-combined',
+      parentControllerIds,
+      winningParentControllerId: getInterruptionSignalId(deadlineSignal),
+      causalEventId: getInterruptionSignalAbortEventId(deadlineSignal),
+    })
   }
   const cleanupAfterHeaders = () => {
     deadlineSignal.removeEventListener('abort', abortFromDeadline)
   }
+  let cleanedUp = false
   const cleanup = () => {
+    if (cleanedUp) return
+    cleanedUp = true
     callerSignal.removeEventListener('abort', abortFromCaller)
     cleanupAfterHeaders()
+    traceInterruptionEvent('combined_signal.cleanup', {
+      subsystem: 'openai_shim_transport',
+      controllerRole: 'request-combined',
+    })
   }
 
   callerSignal.addEventListener('abort', abortFromCaller, { once: true })
@@ -187,6 +238,10 @@ export async function fetchWithHeadersDeadline(
   const redactedUrl = redactUrlForDiagnostics(url)
   const fetchWithAttemptDeadline: ProxyRetryFetcher = async (input, attemptInit) => {
     const deadlineController = new AbortController()
+    registerInterruptionController(deadlineController, {
+      subsystem: 'openai_shim_transport',
+      controllerRole: 'headers-deadline',
+    })
     const timeoutReason = new ResponseHeadersTimeoutError(
       options.timeoutMs,
       redactedUrl,
@@ -198,7 +253,12 @@ export async function fetchWithHeadersDeadline(
       cleanupAfterBody,
     } = combineRequestSignals(options.callerSignal, deadlineController.signal)
     const timer = setTimeout(
-      () => deadlineController.abort(timeoutReason),
+      () =>
+        requestAbort(deadlineController, timeoutReason, {
+          source: 'headers_deadline_timer',
+          subsystem: 'openai_shim_transport',
+          controllerRole: 'headers-deadline',
+        }),
       options.timeoutMs,
     )
     timer.unref?.()

src/services/compact/compact.test.ts

@@ -7,6 +7,7 @@ import {
   expect,
   mock,
   test,
+  vi,
 } from 'bun:test'
 import { randomUUID } from 'crypto'
 import { unlink } from 'fs/promises'
@@ -19,6 +20,11 @@ import {
 } from '../../test/sharedMutationLock.js'
 import type { Message } from '../../types/message.js'
 import * as realConfig from '../../utils/config.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../../utils/interruptionTrace.js'
 
 // Several earlier test files in the smoke suite call
 // mock.module('../../utils/model/providers.js', ...) to stub getAPIProvider.
@@ -815,6 +821,51 @@ afterAll(async () => {
 })
 
 describe('compactConversation provider gate', () => {
+  test('attributes cache-sharing timeout aborts to the compact fork', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    vi.useFakeTimers()
+    try {
+      const runForkedAgent = mock(() => new Promise(() => {}))
+      const { compactConversation } = await importCompact({ runForkedAgent })
+      const messages = [userMessage('Hello'), assistantMessage('Hi there!')]
+      const compactPromise = compactConversation(
+        messages,
+        toolUseContext(),
+        cacheSafeParams(messages),
+        false,
+      )
+
+      for (let attempt = 0; attempt < 10 && runForkedAgent.mock.calls.length === 0; attempt++) {
+        await Promise.resolve()
+      }
+      expect(runForkedAgent).toHaveBeenCalledTimes(1)
+
+      vi.advanceTimersByTime(120_000)
+      await compactPromise
+
+      expect(
+        __getInterruptionTraceSnapshotForTests().find(
+          entry => entry.event === 'abort.requested',
+        ),
+      ).toMatchObject({
+        source: 'compact_timeout',
+        subsystem: 'compact',
+        controllerRole: 'compact-fork',
+      })
+    } finally {
+      vi.useRealTimers()
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) {
+        delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      } else {
+        process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      }
+    }
+  })
+
   test('skips forked-agent cache-sharing for non-Anthropic providers', async () => {
     // Simulate a non-Anthropic provider (e.g. OpenAI) via env vars.
     // The real isAnthropicProvider() reads from process.env and returns false.

src/services/compact/compact.ts

@@ -61,6 +61,7 @@ import {
 } from '../../utils/hooks.js'
 import { logError } from '../../utils/log.js'
 import { MEMORY_TYPE_VALUES } from '../../utils/memory/types.js'
+import { requestAbort } from '../../utils/interruptionTrace.js'
 import {
   createCompactBoundaryMessage,
   createUserMessage,
@@ -139,6 +140,14 @@ export const POST_COMPACT_SKILLS_TOKEN_BUDGET = 25_000
 const MAX_COMPACT_STREAMING_RETRIES = 2
 const COMPACT_TIMEOUT_MS = 120_000
 
+function requestCompactTimeoutAbort(controller: AbortController): void {
+  requestAbort(controller, undefined, {
+    source: 'compact_timeout',
+    subsystem: 'compact',
+    controllerRole: 'compact-fork',
+  })
+}
+
 /**
  * Strip image blocks from user messages before sending for compaction.
  * Images are not needed for generating a conversation summary and can
@@ -1268,7 +1277,10 @@ async function streamCompactSummary({
         // Use a child AbortController that properly propagates parent aborts
         // (user ESC) and cleans up listeners automatically via createChildAbortController.
         const forkAbortController = context.abortController
-          ? createChildAbortController(context.abortController)
+          ? createChildAbortController(context.abortController, undefined, {
+              subsystem: 'compact',
+              controllerRole: 'compact-fork',
+            })
           : new AbortController()
 
         let timeoutId: ReturnType<typeof setTimeout> | undefined
@@ -1298,7 +1310,7 @@ async function streamCompactSummary({
             }),
             new Promise<never>((_, reject) => {
               timeoutId = setTimeout(() => {
-                forkAbortController.abort()
+                requestCompactTimeoutAbort(forkAbortController)
                 reject(new Error('Compaction timed out'))
               }, COMPACT_TIMEOUT_MS)
             }),

src/services/goal/controller.test.ts

@@ -8,6 +8,17 @@ import {
 } from './controller.js'
 import type { GoalState } from './types.js'
 import type { AssistantMessage } from '../../types/message.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  registerInterruptionController,
+  requestAbort,
+} from '../../utils/interruptionTrace.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
 
 function assistant(uuid: string, text: string) {
   // Minimal fixture — cast rather than fabricate the full envelope.
@@ -57,6 +68,66 @@ async function drain(
 }
 
 describe('goal continuation controller', () => {
+  test.serial('traces goal evaluation start and completion', async () => {
+    await acquireSharedMutationLock('goal/controller trace')
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    try {
+      const { context, abortController } = makeContext()
+      registerInterruptionController(abortController, {
+        controllerRole: 'query-root',
+      })
+      await drain(
+        evaluateGoalAfterTurn({
+          messagesForQuery: [],
+          assistantMessages: [assistant('assistant-trace', 'Done.')],
+          toolUseContext: context,
+          querySource: 'repl_main_thread',
+          deps: {
+            evaluateGoal: async () => {
+              requestAbort(abortController, 'user-cancel', {
+                source: 'cancel_keybinding',
+                controllerRole: 'query-root',
+              })
+              return {
+                complete: false,
+                confidence: 0,
+                decision: 'error',
+                reason: 'cancelled',
+                nextInstruction: null,
+              }
+            },
+            saveGoalState: async () => {},
+          },
+        }),
+      )
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      expect(trace.map(entry => entry.event)).toEqual(
+        expect.arrayContaining([
+          'goal.evaluation_started',
+          'goal.evaluation_completed',
+        ]),
+      )
+      const rootAbort = trace.find(entry => entry.event === 'abort.requested')
+      const completed = trace.find(
+        entry => entry.event === 'goal.evaluation_completed',
+      )
+      expect(rootAbort).toBeDefined()
+      expect(completed).toBeDefined()
+      expect(typeof rootAbort!.eventId).toBe('string')
+      expect(typeof completed!.causalEventId).toBe('string')
+      expect(completed!.causalEventId).toBe(rootAbort!.eventId)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      releaseSharedMutationLock()
+    }
+  })
+
   test('evaluator complete => no blocking error, goal achieved', async () => {
     const { context, getState } = makeContext()
     const deps: GoalEvaluationDeps = {

src/services/goal/controller.ts

@@ -5,6 +5,10 @@ import type { ToolUseContext } from '../../Tool.js'
 import type { Message } from '../../types/message.js'
 import { logForDebugging } from '../../utils/debug.js'
 import { logForDiagnosticsNoPII } from '../../utils/diagLogs.js'
+import {
+  getInterruptionSignalAbortEventId,
+  traceInterruptionEvent,
+} from '../../utils/interruptionTrace.js'
 import { createSystemMessage, createUserMessage } from '../../utils/messages.js'
 import { evaluateGoal as evaluateGoalDefault } from './evaluator.js'
 import { buildGoalContinuationInstruction } from './instructions.js'
@@ -173,6 +177,12 @@ export async function* evaluateGoalAfterTurn({
     return []
   }
 
+  traceInterruptionEvent('goal.evaluation_started', {
+    subsystem: 'goal',
+    phase: 'evaluator',
+    querySource,
+    attemptId: goal.id,
+  })
   const decision = await evaluateGoal({
     goal,
     messages: getRecentGoalEvaluationMessages(
@@ -183,6 +193,17 @@ export async function* evaluateGoalAfterTurn({
     isNonInteractiveSession:
       toolUseContext.options.isNonInteractiveSession ?? false,
   })
+  traceInterruptionEvent('goal.evaluation_completed', {
+    subsystem: 'goal',
+    phase: 'evaluator',
+    querySource,
+    attemptId: goal.id,
+    outcome: decision.decision,
+    reason: toolUseContext.abortController.signal.reason,
+    causalEventId: getInterruptionSignalAbortEventId(
+      toolUseContext.abortController.signal,
+    ),
+  })
 
   if (toolUseContext.abortController.signal.aborted) return []
 

src/services/goal/evaluator.test.ts

@@ -6,6 +6,17 @@ import {
   evaluateGoal,
   type GoalModelCaller,
 } from './evaluator.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  registerInterruptionController,
+  requestAbort,
+} from '../../utils/interruptionTrace.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
 
 function user(uuid: string, content: string) {
   return {
@@ -27,6 +38,52 @@ function assistant(uuid: string, content: string) {
 }
 
 describe('goal evaluator', () => {
+  test.serial('traces provider failures without serializing the error message', async () => {
+    await acquireSharedMutationLock('goal/evaluator trace')
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    try {
+      const controller = new AbortController()
+      registerInterruptionController(controller, {
+        controllerRole: 'query-root',
+      })
+      await evaluateGoal({
+        goal: createGoalState('finish implementation'),
+        messages: [],
+        signal: controller.signal,
+        isNonInteractiveSession: false,
+        modelCaller: async () => {
+          requestAbort(controller, 'user-cancel', {
+            source: 'cancel_keybinding',
+            controllerRole: 'query-root',
+          })
+          throw new Error('private provider detail')
+        },
+      })
+
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const serialized = JSON.stringify(trace)
+      expect(serialized).toContain('goal.evaluation_failed')
+      expect(serialized).not.toContain('private provider detail')
+      const rootAbort = trace.find(entry => entry.event === 'abort.requested')
+      const failed = trace.find(
+        entry => entry.event === 'goal.evaluation_failed',
+      )
+      expect(rootAbort).toBeDefined()
+      expect(failed).toBeDefined()
+      expect(typeof rootAbort!.eventId).toBe('string')
+      expect(typeof failed!.causalEventId).toBe('string')
+      expect(failed!.causalEventId).toBe(rootAbort!.eventId)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+      releaseSharedMutationLock()
+    }
+  })
+
   test('valid complete JSON', async () => {
     const caller: GoalModelCaller = async () =>
       JSON.stringify({

src/services/goal/evaluator.ts

@@ -1,5 +1,9 @@
 import type { SystemPrompt } from '../../utils/systemPromptType.js'
 import { asSystemPrompt } from '../../utils/systemPromptType.js'
+import {
+  getInterruptionSignalAbortEventId,
+  traceInterruptionEvent,
+} from '../../utils/interruptionTrace.js'
 import { queryHaiku } from '../api/claude.js'
 import type { GoalEvaluatorDecision, GoalState } from './types.js'
 
@@ -267,7 +271,14 @@ export async function evaluateGoal({
         'Goal evaluator returned malformed JSON; pausing automatic goal continuation.',
       nextInstruction: null,
     }
-  } catch {
+  } catch (error) {
+    traceInterruptionEvent('goal.evaluation_failed', {
+      subsystem: 'goal',
+      phase: 'evaluator',
+      error,
+      reason: signal.reason,
+      causalEventId: getInterruptionSignalAbortEventId(signal),
+    })
     return {
       complete: false,
       confidence: 0,

src/services/tools/StreamingToolExecutor.ts

@@ -13,6 +13,10 @@ import {
   getMissingToolResultAbortMessage,
   shouldCreateUserInterruptionMessage,
 } from '../../utils/abortReasons.js'
+import {
+  getInterruptionSignalAbortEventId,
+  requestAbort,
+} from '../../utils/interruptionTrace.js'
 import { runToolUse } from './toolExecution.js'
 
 type MessageUpdate = {
@@ -66,6 +70,11 @@ export class StreamingToolExecutor {
     this.toolUseContext = toolUseContext
     this.siblingAbortController = createChildAbortController(
       toolUseContext.abortController,
+      undefined,
+      {
+        subsystem: 'streaming_tool_executor',
+        controllerRole: 'sibling-tools',
+      },
     )
   }
 
@@ -77,7 +86,11 @@ export class StreamingToolExecutor {
   discard(): void {
     if (this.discarded) return
     this.discarded = true
-    this.siblingAbortController.abort('streaming_fallback')
+    requestAbort(this.siblingAbortController, 'streaming_fallback', {
+      source: 'streaming_fallback',
+      subsystem: 'streaming_tool_executor',
+      controllerRole: 'sibling-tools',
+    })
     const activeLifecycleToolUseIds = new Set(
       this.toolUseContext.queryLifecycle
         ?.snapshot()
@@ -355,6 +368,11 @@ export class StreamingToolExecutor {
       // sends REJECT_MESSAGE to the model instead of aborting (#21056 regression).
       const toolAbortController = createChildAbortController(
         this.siblingAbortController,
+        undefined,
+        {
+          subsystem: 'streaming_tool_executor',
+          controllerRole: 'tool',
+        },
       )
       toolAbortController.signal.addEventListener(
         'abort',
@@ -364,8 +382,17 @@ export class StreamingToolExecutor {
             !this.toolUseContext.abortController.signal.aborted &&
             !this.discarded
           ) {
-            this.toolUseContext.abortController.abort(
+            requestAbort(
+              this.toolUseContext.abortController,
               toolAbortController.signal.reason,
+              {
+                source: 'tool_abort_propagation',
+                causalEventId: getInterruptionSignalAbortEventId(
+                  toolAbortController.signal,
+                ),
+                subsystem: 'streaming_tool_executor',
+                controllerRole: 'query-root',
+              },
             )
           }
         },
@@ -414,7 +441,11 @@ export class StreamingToolExecutor {
           if (tool.block.name === BASH_TOOL_NAME) {
             this.hasErrored = true
             this.erroredToolDescription = this.getToolDescription(tool)
-            this.siblingAbortController.abort('sibling_error')
+            requestAbort(this.siblingAbortController, 'sibling_error', {
+              source: 'sibling_error',
+              subsystem: 'streaming_tool_executor',
+              controllerRole: 'sibling-tools',
+            })
           }
         }
 

src/state/teammateViewHelpers.interruptionTrace.test.ts

@@ -0,0 +1,82 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import type { AppState } from './AppState.js'
+import { getDefaultAppState } from './AppStateStore.js'
+import { stopOrDismissAgent } from './teammateViewHelpers.js'
+import type { LocalAgentTaskState } from '../tasks/LocalAgentTask/LocalAgentTask.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../utils/interruptionTrace.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../test/sharedMutationLock.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock(
+    'state/teammateViewHelpers.interruptionTrace.test.ts',
+  )
+})
+
+afterEach(() => {
+  try {
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+test('records the panel stop source and causal input before aborting an agent', () => {
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  const abortController = new AbortController()
+  const taskId = 'agent-task-1'
+  const task = {
+    id: taskId,
+    type: 'local_agent',
+    status: 'running',
+    description: 'test agent',
+    startTime: Date.now(),
+    outputFile: '/tmp/test-agent-output',
+    outputOffset: 0,
+    notified: false,
+    agentId: 'agent-1',
+    prompt: 'test',
+    agentType: 'general-purpose',
+    abortController,
+    retrieved: false,
+    lastReportedToolCount: 0,
+    lastReportedTokenCount: 0,
+    isBackgrounded: true,
+    pendingMessages: [],
+    retain: false,
+    diskLoaded: false,
+  } satisfies LocalAgentTaskState
+  let state: AppState = {
+    ...getDefaultAppState(),
+    tasks: { [taskId]: task },
+  }
+
+  stopOrDismissAgent(taskId, updater => {
+    state = updater(state)
+  })
+
+  const entries = __getInterruptionTraceSnapshotForTests()
+  const input = entries.find(entry => entry.event === 'input.agent_panel_stop')
+  const requested = entries.find(entry => entry.event === 'abort.requested')
+  expect(abortController.signal.aborted).toBe(true)
+  expect(input).toBeDefined()
+  expect(requested).toMatchObject({
+    source: 'agent_panel_stop',
+    subsystem: 'local_agent_task',
+    controllerRole: 'background-agent',
+    subagentId: taskId,
+    causalEventId: input?.eventId,
+  })
+})

src/state/teammateViewHelpers.ts

@@ -1,6 +1,10 @@
 import { logEvent } from '../services/analytics/index.js'
 import { isTerminalTaskStatus } from '../Task.js'
 import type { LocalAgentTaskState } from '../tasks/LocalAgentTask/LocalAgentTask.js'
+import {
+  requestAbort,
+  traceInterruptionEvent,
+} from '../utils/interruptionTrace.js'
 
 // Inlined from framework.ts — importing creates a cycle through
 // BackgroundTasksDialog. Keep in sync with PANEL_GRACE_MS there.
@@ -121,7 +125,20 @@ export function stopOrDismissAgent(
     const task = prev.tasks[taskId]
     if (!isLocalAgent(task)) return prev
     if (task.status === 'running') {
-      task.abortController?.abort()
+      const causalEventId = traceInterruptionEvent('input.agent_panel_stop', {
+        source: 'agent_panel_stop',
+        subsystem: 'local_agent_task',
+        subagentId: taskId,
+      })
+      if (task.abortController) {
+        requestAbort(task.abortController, undefined, {
+          source: 'agent_panel_stop',
+          subsystem: 'local_agent_task',
+          controllerRole: 'background-agent',
+          subagentId: taskId,
+          causalEventId,
+        })
+      }
       return prev
     }
     if (task.evictAfter === 0) return prev

src/tasks/LocalAgentTask/LocalAgentTask.tsx

@@ -16,6 +16,7 @@ import { registerCleanup } from '../../utils/cleanupRegistry.js';
 import { getToolSearchOrReadInfo } from '../../utils/collapseReadSearch.js';
 import { enqueuePendingNotification } from '../../utils/messageQueueManager.js';
 import { getAgentTranscriptPath } from '../../utils/sessionStorage.js';
+import { requestAbort } from '../../utils/interruptionTrace.js';
 import { evictTaskOutput, getTaskOutputPath, initTaskOutputAsSymlink } from '../../utils/task/diskOutput.js';
 import { PANEL_GRACE_MS, registerTask, updateTaskState } from '../../utils/task/framework.js';
 import { emitTaskProgress } from '../../utils/task/sdkProgress.js';
@@ -271,21 +272,34 @@ export const LocalAgentTask: Task = {
   name: 'LocalAgentTask',
   type: 'local_agent',
   async kill(taskId, setAppState) {
-    killAsyncAgent(taskId, setAppState);
+    killAsyncAgent(taskId, setAppState, { source: 'task_stop' });
   }
 };
 
 /**
  * Kill an agent task. No-op if already killed/completed.
  */
-export function killAsyncAgent(taskId: string, setAppState: SetAppState): void {
+export type AgentKillTrace = {
+  source: string;
+  causalEventId?: string;
+};
+
+export function killAsyncAgent(taskId: string, setAppState: SetAppState, trace: AgentKillTrace = { source: 'agent_cleanup' }): void {
   let killed = false;
   updateTaskState<LocalAgentTaskState>(taskId, setAppState, task => {
     if (task.status !== 'running') {
       return task;
     }
     killed = true;
-    task.abortController?.abort();
+    if (task.abortController && !task.abortController.signal.aborted) {
+      requestAbort(task.abortController, undefined, {
+        source: trace.source,
+        subsystem: 'local_agent_task',
+        controllerRole: 'background-agent',
+        subagentId: taskId,
+        causalEventId: trace.causalEventId
+      });
+    }
     task.unregisterCleanup?.();
     return {
       ...task,
@@ -306,10 +320,10 @@ export function killAsyncAgent(taskId: string, setAppState: SetAppState): void {
  * Kill all running agent tasks.
  * Used by ESC cancellation in coordinator mode to stop all subagents.
  */
-export function killAllRunningAgentTasks(tasks: Record<string, TaskState>, setAppState: SetAppState): void {
+export function killAllRunningAgentTasks(tasks: Record<string, TaskState>, setAppState: SetAppState, trace: AgentKillTrace): void {
   for (const [taskId, task] of Object.entries(tasks)) {
     if (task.type === 'local_agent' && task.status === 'running') {
-      killAsyncAgent(taskId, setAppState);
+      killAsyncAgent(taskId, setAppState, trace);
     }
   }
 }
@@ -483,7 +497,13 @@ export function registerAsyncAgent({
   void initTaskOutputAsSymlink(agentId, getAgentTranscriptPath(asAgentId(agentId)));
 
   // Create abort controller - if parent provided, create child that auto-aborts with parent
-  const abortController = parentAbortController ? createChildAbortController(parentAbortController) : createAbortController();
+  const abortController = parentAbortController
+    ? createChildAbortController(parentAbortController, undefined, {
+        subsystem: 'local_agent_task',
+        controllerRole: 'background-agent',
+        subagentId: agentId,
+      })
+    : createAbortController();
   const taskState: LocalAgentTaskState = {
     ...createTaskStateBase(agentId, 'local_agent', description, toolUseId),
     type: 'local_agent',

src/test/fixtures/gracefulShutdownTrace.fixture.ts

@@ -0,0 +1,61 @@
+import { getFsImplementation, setFsImplementation } from '../../utils/fsOperations.js'
+import { gracefulShutdown, resetShutdownState } from '../../utils/gracefulShutdown.js'
+import {
+  __resetInterruptionTraceForTests,
+  requestAbort,
+  traceInterruptionEvent,
+} from '../../utils/interruptionTrace.js'
+
+process.env.NODE_ENV = 'test'
+process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/virtual/trace.jsonl'
+
+const originalFs = getFsImplementation()
+const originalExit = process.exit
+let writeSettled = false
+let exitObservedSettledWrite = false
+let exitCalled = false
+
+setFsImplementation({
+  ...originalFs,
+  mkdirSync: () => {},
+  appendRegularFile: async () => {
+    if (process.env.TRACE_SHUTDOWN_BLOCK_WRITE === '1') {
+      await new Promise<void>(() => {})
+    }
+    await Bun.sleep(50)
+    writeSettled = true
+  },
+})
+process.exit = ((_code?: number) => {
+  exitCalled = true
+  exitObservedSettledWrite = writeSettled
+  throw new Error('mocked process exit')
+}) as typeof process.exit
+
+try {
+  const controller = new AbortController()
+  if (process.env.TRACE_SHUTDOWN_PENDING_ONLY === '1') {
+    controller.abort('interrupt')
+    traceInterruptionEvent('shutdown.pending')
+  } else {
+    requestAbort(controller, 'interrupt', {
+      source: 'print_sigint',
+      controllerRole: 'query-root',
+    })
+  }
+  await gracefulShutdown(0).catch(() => {})
+  console.log(
+    `TRACE_SHUTDOWN_RESULT ${JSON.stringify({
+      aborted: controller.signal.aborted,
+      exitCalled,
+      writeSettled,
+      exitObservedSettledWrite,
+    })}`,
+  )
+} finally {
+  process.exit = originalExit
+  setFsImplementation(originalFs)
+  resetShutdownState()
+  __resetInterruptionTraceForTests()
+}

src/tools/SendMessageTool/SendMessageTool.ts

@@ -40,6 +40,7 @@ import {
 } from '../../utils/teammateMailbox.js'
 import { resumeAgentBackground } from '../AgentTool/resumeAgent.js'
 import { SEND_MESSAGE_TOOL_NAME } from './constants.js'
+import { abortApprovedInProcessTeammate } from './shutdownInterruptionTrace.js'
 import { DESCRIPTION, getPrompt } from './prompt.js'
 import { renderToolResultMessage, renderToolUseMessage } from './UI.js'
 
@@ -354,7 +355,9 @@ async function handleShutdownApproval(
       const appState = context.getAppState()
       const task = findTeammateTaskByAgentId(agentId, appState.tasks)
       if (task?.abortController) {
-        task.abortController.abort()
+        abortApprovedInProcessTeammate(task.abortController, {
+          agentId,
+        })
         logForDebugging(
           `[SendMessageTool] Aborted controller for in-process teammate ${agentName}`,
         )
@@ -372,7 +375,9 @@ async function handleShutdownApproval(
         logForDebugging(
           `[SendMessageTool] Fallback: Found in-process task for ${agentName} via AppState, aborting`,
         )
-        task.abortController.abort()
+        abortApprovedInProcessTeammate(task.abortController, {
+          agentId,
+        })
 
         return {
           data: {

src/tools/SendMessageTool/shutdownInterruptionTrace.test.ts

@@ -0,0 +1,66 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  registerInterruptionController,
+} from '../../utils/interruptionTrace.js'
+import { abortApprovedInProcessTeammate } from './shutdownInterruptionTrace.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('shutdownInterruptionTrace.test.ts')
+})
+
+afterEach(async () => {
+  try {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+test('shutdown approval records its input before requesting the teammate abort', () => {
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  const controller = new AbortController()
+  registerInterruptionController(controller, {
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: 'agent-1',
+  })
+
+  abortApprovedInProcessTeammate(controller, {
+    agentId: 'agent-1',
+  })
+
+  expect(controller.signal.aborted).toBe(true)
+  expect(controller.signal.reason).toBeInstanceOf(DOMException)
+  expect((controller.signal.reason as DOMException).name).toBe('AbortError')
+  const trace = __getInterruptionTraceSnapshotForTests()
+  const approved = trace.find(
+    entry => entry.event === 'teammate.shutdown_approved',
+  )
+  const requested = trace.find(entry => entry.event === 'abort.requested')
+  expect(approved).toMatchObject({
+    source: 'shutdown_approved',
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: 'agent-1',
+  })
+  expect(requested).toMatchObject({
+    source: 'shutdown_approved',
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: 'agent-1',
+    causalEventId: approved?.eventId,
+  })
+  expect(trace.indexOf(approved!)).toBeLessThan(trace.indexOf(requested!))
+})

src/tools/SendMessageTool/shutdownInterruptionTrace.ts

@@ -0,0 +1,23 @@
+import {
+  requestAbort,
+  traceInterruptionEvent,
+} from '../../utils/interruptionTrace.js'
+
+export function abortApprovedInProcessTeammate(
+  controller: AbortController,
+  identity: { agentId: string },
+): void {
+  const causalEventId = traceInterruptionEvent('teammate.shutdown_approved', {
+    source: 'shutdown_approved',
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: identity.agentId,
+  })
+  requestAbort(controller, undefined, {
+    source: 'shutdown_approved',
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: identity.agentId,
+    causalEventId,
+  })
+}

src/utils/QueryGuard.ts

@@ -29,6 +29,10 @@
  *   )
  */
 import { createSignal } from './signal.js'
+import {
+  flushInterruptionTrace,
+  traceInterruptionEvent,
+} from './interruptionTrace.js'
 import type {
   QueryActiveOperationSnapshot,
   QueryGuardMetadata,
@@ -127,6 +131,8 @@ export class QueryGuard {
   private _suspendedAt = 0
   private _totalSuspendedMs = 0
   private _leaseCounter = 0
+  private _traceActivityCount = 0
+  private _lastTraceActivityAt = 0
   private _activeLeases = new Map<string, LeaseRecord>()
   private _context: QueryLifecycleContext | null = null
   private _lastContext: QueryLifecycleContext | null = null
@@ -190,8 +196,17 @@ export class QueryGuard {
     this._totalSuspendedMs = 0
     this._lastContext = null
     this._queryStartedAt = performance.now()
+    this._traceActivityCount = 0
+    this._lastTraceActivityAt = 0
     this._lastActivityAt = this._queryStartedAt
     this._context = this._createContext(metadata)
+    traceInterruptionEvent('query_guard.started', {
+      subsystem: 'query_guard',
+      phase: 'running',
+      queryId: this._context.queryId,
+      queryGeneration: this._generation,
+      querySource: this._context.querySource,
+    })
     this._getActiveOperations = metadata?.getActiveOperations ?? null
     this._startTimeout()
     this._notify()
@@ -221,7 +236,16 @@ export class QueryGuard {
     this._suspendCount = 0
     this._suspendedAt = 0
     this._totalSuspendedMs = 0
+    const context = this._context
     this._completeContext(terminalReason, abortReason)
+    traceInterruptionEvent('query_guard.ended', {
+      subsystem: 'query_guard',
+      phase: terminalReason,
+      queryId: context?.queryId,
+      queryGeneration: generation,
+      querySource: context?.querySource,
+      reason: abortReason,
+    })
     this._status = 'idle'
     this._getActiveOperations = null
     this._notify()
@@ -244,7 +268,16 @@ export class QueryGuard {
     this._suspendCount = 0
     this._suspendedAt = 0
     this._totalSuspendedMs = 0
+    const context = this._context
     this._completeContext(terminalReason, abortReason)
+    traceInterruptionEvent('query_guard.force_ended', {
+      subsystem: 'query_guard',
+      phase: terminalReason,
+      queryId: context?.queryId,
+      queryGeneration: this._generation,
+      querySource: context?.querySource,
+      reason: abortReason,
+    })
     this._status = 'idle'
     this._getActiveOperations = null
     ++this._generation
@@ -260,7 +293,22 @@ export class QueryGuard {
     void reason
     if (this._status !== 'running') return
     if (generation !== undefined && generation !== this._generation) return
-    this._lastActivityAt = performance.now()
+    const now = performance.now()
+    this._lastActivityAt = now
+    this._traceActivityCount++
+    if (
+      this._traceActivityCount === 1 ||
+      now - this._lastTraceActivityAt >= 5_000
+    ) {
+      this._lastTraceActivityAt = now
+      traceInterruptionEvent('query_guard.activity', {
+        subsystem: 'query_guard',
+        queryId: this._context?.queryId,
+        queryGeneration: this._generation,
+        querySource: this._context?.querySource,
+        yieldedEventCount: this._traceActivityCount,
+      })
+    }
     this._scheduleTimeout()
   }
 
@@ -314,6 +362,13 @@ export class QueryGuard {
       deadlineAt: leaseDeadlineAt,
       description: input.description,
     })
+    traceInterruptionEvent('query_guard.lease_acquired', {
+      subsystem: 'query_guard',
+      queryId: this._context?.queryId,
+      queryGeneration: this._generation,
+      source: input.owner,
+      leaseCount: this._activeLeases.size,
+    })
     this._lastActivityAt = now
     this._scheduleTimeout()
 
@@ -331,6 +386,13 @@ export class QueryGuard {
     const lease = this._activeLeases.get(leaseId)
     if (!lease || lease.generation !== generation) return
     this._activeLeases.delete(leaseId)
+    traceInterruptionEvent('query_guard.lease_released', {
+      subsystem: 'query_guard',
+      queryId: this._context?.queryId,
+      queryGeneration: this._generation,
+      source: lease.owner,
+      leaseCount: this._activeLeases.size,
+    })
     this._scheduleTimeout()
   }
 
@@ -352,6 +414,12 @@ export class QueryGuard {
       this._suspendedAt = performance.now()
     }
     this._suspendCount++
+    traceInterruptionEvent('query_guard.suspended', {
+      subsystem: 'query_guard',
+      queryId: this._context?.queryId,
+      queryGeneration: this._generation,
+      suspendCount: this._suspendCount,
+    })
     this._scheduleTimeout()
 
     let resumed = false
@@ -362,6 +430,12 @@ export class QueryGuard {
       if (generation !== this._generation) return
       if (this._suspendCount === 0) return
       this._suspendCount--
+      traceInterruptionEvent('query_guard.resumed', {
+        subsystem: 'query_guard',
+        queryId: this._context?.queryId,
+        queryGeneration: this._generation,
+        suspendCount: this._suspendCount,
+      })
       if (this._suspendCount === 0) {
         this._resumeAfterInteraction()
       }
@@ -534,6 +608,21 @@ export class QueryGuard {
       context,
       activeOperations: this._snapshotActiveOperations(),
     }
+    const causalEventId = traceInterruptionEvent('query_guard.fired', {
+      subsystem: 'query_guard',
+      phase: terminalReason,
+      queryId: context.queryId,
+      queryGeneration: context.queryGeneration,
+      querySource: context.querySource,
+      trigger: reason,
+      elapsedQueryMs: timeout.elapsedMs,
+      sinceLastActivityMs: now - this._lastActivityAt,
+      activeApiCallCount: timeout.activeOperations.apiCalls.length,
+      activeToolUseCount: timeout.activeOperations.toolUses.length,
+      leaseCount: this._activeLeases.size,
+      suspendCount: this._suspendCount,
+    })
+    if (causalEventId) timeout.causalEventId = causalEventId
 
     console.error(
       `[QueryGuard] Query ${reason} timeout - force-ending to prevent infinite spinner`,
@@ -544,6 +633,7 @@ export class QueryGuard {
       console.error('[QueryGuard] Timeout handler failed', error)
     } finally {
       this.forceEnd(terminalReason, reason)
+      flushInterruptionTrace('query_guard_timeout')
     }
   }
 

src/utils/abortController.ts

@@ -1,4 +1,11 @@
 import { setMaxListeners } from 'events'
+import {
+  getInterruptionSignalAbortEventId,
+  getInterruptionSignalId,
+  registerInterruptionController,
+  requestAbort,
+  type InterruptionTraceFields,
+} from './interruptionTrace.js'
 
 /**
  * Default max listeners for standard operations
@@ -32,7 +39,19 @@ function propagateAbort(
   weakChild: WeakRef<AbortController>,
 ): void {
   const parent = this.deref()
-  weakChild.deref()?.abort(parent?.signal.reason)
+  const child = weakChild.deref()
+  if (!child) return
+  requestAbort(child, parent?.signal.reason, {
+    source: 'parent_signal',
+    subsystem: 'abort_controller',
+    controllerRole: 'child',
+    ...(parent && {
+      causalEventId: getInterruptionSignalAbortEventId(parent.signal),
+    }),
+    ...(parent && {
+      parentControllerIds: [getInterruptionSignalId(parent.signal) ?? 'unregistered-parent'],
+    }),
+  })
 }
 
 /**
@@ -63,17 +82,40 @@ function removeAbortHandler(
  *
  * @param parent - The parent AbortController
  * @param maxListeners - Maximum number of listeners (default: 50)
+ * @param traceFields - Owning lifecycle identity for interruption diagnostics
  * @returns Child AbortController
  */
 export function createChildAbortController(
   parent: AbortController,
   maxListeners?: number,
+  traceFields: InterruptionTraceFields = {},
 ): AbortController {
   const child = createAbortController(maxListeners)
+  const parentId = registerInterruptionController(parent, {
+    subsystem: 'abort_controller',
+    controllerRole: 'parent',
+  }, { provisionalRole: true })
+  const hasOwningRole = traceFields.controllerRole !== undefined
+  registerInterruptionController(
+    child,
+    {
+      subsystem: 'abort_controller',
+      controllerRole: 'child',
+      ...traceFields,
+      ...(parentId && { parentControllerIds: [parentId] }),
+    },
+    { provisionalRole: !hasOwningRole },
+  )
 
   // Fast path: parent already aborted, no listener setup needed
   if (parent.signal.aborted) {
-    child.abort(parent.signal.reason)
+    requestAbort(child, parent.signal.reason, {
+      source: 'already_aborted_parent',
+      subsystem: 'abort_controller',
+      controllerRole: 'child',
+      causalEventId: getInterruptionSignalAbortEventId(parent.signal),
+      ...(parentId && { parentControllerIds: [parentId] }),
+    })
     return child
   }
 

src/utils/attachments.ts

@@ -2699,7 +2699,14 @@ export function startRelevantMemoryPrefetch(
 
   // Chained to the turn-level abort so user Escape cancels the sideQuery
   // immediately, not just on [Symbol.dispose] when queryLoop exits.
-  const controller = createChildAbortController(toolUseContext.abortController)
+  const controller = createChildAbortController(
+    toolUseContext.abortController,
+    undefined,
+    {
+      subsystem: 'memory_attachments',
+      controllerRole: 'memory-prefetch',
+    },
+  )
   const firedAt = Date.now()
   const promise = getRelevantMemoryAttachments(
     input,

src/utils/combinedAbortSignal.ts

@@ -1,4 +1,12 @@
 import { createAbortController } from './abortController.js'
+import {
+  getInterruptionSignalAbortEventId,
+  getInterruptionSignalId,
+  registerInterruptionSignal,
+  requestAbort,
+  traceCombinedSignal,
+  traceInterruptionEvent,
+} from './interruptionTrace.js'
 
 /**
  * Creates a combined AbortSignal that aborts when the input signal aborts,
@@ -14,17 +22,47 @@ import { createAbortController } from './abortController.js'
  */
 export function createCombinedAbortSignal(
   signal: AbortSignal | undefined,
-  opts?: { signalB?: AbortSignal; timeoutMs?: number },
+  opts?: {
+    signalB?: AbortSignal
+    timeoutMs?: number
+    trace?: { subsystem: string; controllerRole?: string }
+  },
 ): { signal: AbortSignal; cleanup: () => void } {
-  const { signalB, timeoutMs } = opts ?? {}
+  const { signalB, timeoutMs, trace } = opts ?? {}
   const combined = createAbortController()
+  const traceFields = {
+    subsystem: trace?.subsystem ?? 'combined_abort_signal',
+    controllerRole: trace?.controllerRole ?? 'combined',
+  }
+  const parentIds = [signal, signalB]
+    .filter((parent): parent is AbortSignal => parent !== undefined)
+    .map(parent =>
+      registerInterruptionSignal(parent, {
+        ...traceFields,
+        controllerRole: 'combined-parent',
+      }),
+    )
+    .filter((id): id is string => id !== undefined)
+  traceCombinedSignal(combined, [signal, signalB], traceFields)
 
   if (signal?.aborted) {
-    combined.abort(signal.reason)
+    requestAbort(combined, signal.reason, {
+      ...traceFields,
+      source: 'signal_a_already_aborted',
+      parentControllerIds: parentIds,
+      winningParentControllerId: getInterruptionSignalId(signal),
+      causalEventId: getInterruptionSignalAbortEventId(signal),
+    })
     return { signal: combined.signal, cleanup: () => {} }
   }
   if (signalB?.aborted) {
-    combined.abort(signalB.reason)
+    requestAbort(combined, signalB.reason, {
+      ...traceFields,
+      source: 'signal_b_already_aborted',
+      parentControllerIds: parentIds,
+      winningParentControllerId: getInterruptionSignalId(signalB),
+      causalEventId: getInterruptionSignalAbortEventId(signalB),
+    })
     return { signal: combined.signal, cleanup: () => {} }
   }
 
@@ -39,15 +77,35 @@ export function createCombinedAbortSignal(
     }
     signal?.removeEventListener('abort', abortFromSignal)
     signalB?.removeEventListener('abort', abortFromSignalB)
+    traceInterruptionEvent('combined_signal.cleanup', traceFields)
   }
-  const abortCombined = (reason?: unknown) => {
+  const abortCombined = (
+    reason: unknown,
+    source: string,
+    winningParent?: AbortSignal,
+  ) => {
     cleanup()
-    combined.abort(reason)
+    requestAbort(combined, reason, {
+      ...traceFields,
+      source,
+      parentControllerIds: parentIds,
+      winningParentControllerId: winningParent
+        ? getInterruptionSignalId(winningParent)
+        : undefined,
+      causalEventId: winningParent
+        ? getInterruptionSignalAbortEventId(winningParent)
+        : undefined,
+    })
   }
-  const abortFromSignal = () => abortCombined(signal?.reason)
+  const abortFromSignal = () =>
-  const abortFromSignalB = () => abortCombined(signalB?.reason)
+    abortCombined(signal?.reason, 'signal_a', signal)
+  const abortFromSignalB = () =>
+    abortCombined(signalB?.reason, 'signal_b', signalB)
   const abortFromTimeout = () =>
-    abortCombined(new DOMException('The operation timed out.', 'TimeoutError'))
+    abortCombined(
+      new DOMException('The operation timed out.', 'TimeoutError'),
+      'timeout',
+    )
 
   if (timeoutMs !== undefined) {
     timer = setTimeout(abortFromTimeout, timeoutMs)

src/utils/computerUse/wrapper.tsx

@@ -22,6 +22,7 @@ import { getSessionId } from '../../bootstrap/state.js';
 import { ComputerUseApproval } from '../../components/permissions/ComputerUseApproval/ComputerUseApproval.js';
 import type { Tool, ToolUseContext } from '../../Tool.js';
 import { logForDebugging } from '../debug.js';
+import { requestAbort } from '../interruptionTrace.js';
 import { checkComputerUseLock, tryAcquireComputerUseLock } from './computerUseLock.js';
 import { registerEscHotkey } from './escHotkey.js';
 import { getChicagoCoordinateMode } from './gates.js';
@@ -219,7 +220,11 @@ export function buildSessionContext(): ComputerUseSessionContext {
         // holds a pump retain until unregisterEscHotkey() in cleanup.ts.
         const escRegistered = registerEscHotkey(() => {
           logForDebugging('[cu-esc] user escape, aborting turn');
-          tuc().abortController.abort();
+          requestAbort(tuc().abortController, undefined, {
+            source: 'computer_use_escape',
+            subsystem: 'computer_use',
+            controllerRole: 'tool',
+          });
         });
         tuc().sendOSNotification?.({
           message: escRegistered ? 'Claude is using your computer · press Esc to stop' : 'Claude is using your computer · press Ctrl+C to stop',

src/utils/diagLogs.ts

@@ -1,4 +1,5 @@
 import { dirname } from 'path'
+import { getErrnoCode } from './errors.js'
 import { getFsImplementation } from './fsOperations.js'
 import { jsonStringify } from './slowOperations.js'
 
@@ -11,6 +12,40 @@ type DiagnosticLogEntry = {
   data: Record<string, unknown>
 }
 
+export type DiagnosticAppendResult =
+  | 'committed'
+  | 'unsupported'
+  | 'retryable_failure'
+  | 'uncertain_failure'
+
+/**
+ * Append already-sanitized diagnostic records to an explicit file.
+ *
+ * This is the shared filesystem boundary for opt-in diagnostic streams. Callers
+ * must rebuild records from an allowlist before using it; arbitrary runtime
+ * objects, messages, prompts, and file paths are not safe inputs.
+ */
+export async function appendDiagnosticsNoPII(
+  logFile: string,
+  entries: readonly Record<string, unknown>[],
+): Promise<DiagnosticAppendResult> {
+  if (entries.length === 0) return 'committed'
+  // Node exposes the descriptor-relative namespace required by the secure
+  // append implementation through /proc/self/fd on Linux only.
+  if (process.platform !== 'linux') return 'unsupported'
+
+  try {
+    const fs = getFsImplementation()
+    const lines = entries.map(entry => jsonStringify(entry)).join('\n') + '\n'
+    await fs.appendRegularFile(logFile, lines, { mode: 0o600 })
+    return 'committed'
+  } catch (error) {
+    return getErrnoCode(error) === 'ERR_DIAGNOSTIC_APPEND_UNCERTAIN'
+      ? 'uncertain_failure'
+      : 'retryable_failure'
+  }
+}
+
 /**
  * Logs diagnostic information to a logfile. This information is sent
  * via the environment manager to session-ingress to monitor issues from
@@ -46,12 +81,12 @@ export function logForDiagnosticsNoPII(
   try {
     fs.appendFileSync(logFile, line)
   } catch {
-    // If append fails, try creating the directory first
+    // Preserve the legacy diagnostic logger's append-through-symlink contract.
     try {
       fs.mkdirSync(dirname(logFile))
       fs.appendFileSync(logFile, line)
     } catch {
-      // Silently fail if logging is not possible
+      // Silently fail if logging is not possible.
     }
   }
 }

src/utils/forkedAgent.ts

@@ -358,7 +358,11 @@ export function createSubagentContext(
     overrides?.abortController ??
     (overrides?.shareAbortController
       ? parentContext.abortController
-      : createChildAbortController(parentContext.abortController))
+      : createChildAbortController(parentContext.abortController, undefined, {
+          subsystem: 'forked_agent',
+          controllerRole: 'subagent-context',
+          subagentId: overrides?.agentId,
+        }))
 
   // Determine getAppState - wrap to set shouldAvoidPermissionPrompts unless sharing abortController
   // (if sharing abortController, it's an interactive agent that CAN show UI)

src/utils/fsOperations.ts

@@ -97,6 +97,18 @@ export type FsOperations = {
   }
   /** Appends string to file */
   appendFileSync(path: string, data: string, options?: { mode?: number }): void
+  /**
+   * Opens a regular file without following path symlinks and appends data.
+   *
+   * Linux only and requires an absolute path; throws on unsupported platforms
+   * or relative paths. A partial write that cannot be rolled back rejects with
+   * `ERR_DIAGNOSTIC_APPEND_UNCERTAIN`.
+   */
+  appendRegularFile(
+    path: string,
+    data: string,
+    options?: { mode?: number },
+  ): Promise<void>
   /** Copies file from source to destination */
   copyFileSync(src: string, dest: string): void
   /** Deletes file */
@@ -546,6 +558,103 @@ export const NodeFsOperations: FsOperations = {
     fs.appendFileSync(path, data)
   },
 
+  async appendRegularFile(path, data, options) {
+    if (process.platform !== 'linux') {
+      throw new Error('Secure diagnostic file output is available on Linux only')
+    }
+    if (!nodePath.isAbsolute(path)) {
+      throw new Error('Secure diagnostic file output requires an absolute path')
+    }
+
+    const resolvedPath = nodePath.resolve(path)
+    const components = nodePath
+      .relative(nodePath.parse(resolvedPath).root, nodePath.dirname(resolvedPath))
+      .split(nodePath.sep)
+      .filter(Boolean)
+    const directoryFlags = fs.constants.O_RDONLY |
+      fs.constants.O_DIRECTORY |
+      fs.constants.O_NOFOLLOW
+    const descriptorDirectory = '/proc/self/fd'
+    let directoryHandle = await open('/', directoryFlags)
+    let committed = false
+    let operationError: unknown
+
+    try {
+      for (const component of components) {
+        const descriptorPath = `${descriptorDirectory}/${directoryHandle.fd}/${component}`
+        let nextDirectoryHandle
+        try {
+          nextDirectoryHandle = await open(descriptorPath, directoryFlags)
+        } catch (error) {
+          if (getErrnoCode(error) !== 'ENOENT') throw error
+          await mkdirPromise(descriptorPath, { mode: 0o700 })
+          nextDirectoryHandle = await open(descriptorPath, directoryFlags)
+        }
+        try {
+          await directoryHandle.close()
+        } catch (error) {
+          await nextDirectoryHandle.close().catch(() => {})
+          throw error
+        }
+        directoryHandle = nextDirectoryHandle
+      }
+
+      const descriptorPath = `${descriptorDirectory}/${directoryHandle.fd}/${nodePath.basename(resolvedPath)}`
+      const flags = fs.constants.O_APPEND |
+      fs.constants.O_CREAT |
+      fs.constants.O_NONBLOCK |
+      fs.constants.O_WRONLY |
+      fs.constants.O_NOFOLLOW
+      const handle = await open(descriptorPath, flags, options?.mode ?? 0o600)
+      let fileOperationError: unknown
+      try {
+        const stats = await handle.stat()
+        if (!stats.isFile()) {
+          throw new Error('Diagnostics target is not a regular file')
+        }
+        if (options?.mode !== undefined) await handle.chmod(options.mode)
+        try {
+          await handle.writeFile(data, { encoding: 'utf8' })
+          committed = true
+        } catch (error) {
+          try {
+            await handle.truncate(stats.size)
+          } catch (rollbackError) {
+            throw Object.assign(
+              new Error('Diagnostic append may have partially committed', {
+                cause: rollbackError,
+              }),
+              { code: 'ERR_DIAGNOSTIC_APPEND_UNCERTAIN' },
+            )
+          }
+          throw error
+        }
+      } catch (error) {
+        fileOperationError = error
+      }
+      try {
+        await handle.close()
+      } catch (error) {
+        // A close failure after writeFile completed cannot safely be interpreted
+        // as a failed append; replaying would duplicate the committed batch.
+        if (!committed && fileOperationError === undefined) {
+          fileOperationError = error
+        }
+      }
+      if (fileOperationError !== undefined) throw fileOperationError
+    } catch (error) {
+      operationError = error
+    }
+    try {
+      await directoryHandle.close()
+    } catch (error) {
+      // Preserve an earlier operation error so a cleanup failure cannot hide an
+      // uncertain commit and cause the caller to replay the same batch.
+      if (!committed && operationError === undefined) operationError = error
+    }
+    if (operationError !== undefined) throw operationError
+  },
+
   copyFileSync(src, dest) {
     using _ = slowLogging`fs.copyFileSync(${src} → ${dest})`
     fs.copyFileSync(src, dest)

src/utils/gracefulShutdown.interruptionTrace.test.ts

@@ -0,0 +1,60 @@
+import { expect, test } from 'bun:test'
+import { spawnSync } from 'node:child_process'
+import { resolve } from 'node:path'
+
+const testLinuxTraceFile = process.platform === 'linux' ? test : test.skip
+
+function runFixture(extraEnv: NodeJS.ProcessEnv = {}): {
+  aborted: boolean
+  exitCalled: boolean
+  writeSettled: boolean
+  exitObservedSettledWrite: boolean
+} {
+  const fixture = resolve(
+    import.meta.dirname,
+    '../test/fixtures/gracefulShutdownTrace.fixture.ts',
+  )
+  const result = spawnSync(process.execPath, [fixture], {
+    encoding: 'utf8',
+    timeout: 15_000,
+    env: { ...process.env, FORCE_COLOR: '0', ...extraEnv },
+  })
+  if (result.error) throw result.error
+  if (result.status !== 0) {
+    throw new Error(
+      `fixture exited with ${result.status}\nstderr:\n${result.stderr}`,
+    )
+  }
+  const resultLine = result.stdout
+    .split('\n')
+    .find(line => line.startsWith('TRACE_SHUTDOWN_RESULT '))
+  expect(resultLine).toBeDefined()
+  return JSON.parse(resultLine!.slice('TRACE_SHUTDOWN_RESULT '.length))
+}
+
+testLinuxTraceFile('graceful shutdown drains the interruption trace before process exit', () => {
+  expect(runFixture()).toEqual({
+    aborted: true,
+    exitCalled: true,
+    writeSettled: true,
+    exitObservedSettledWrite: true,
+  })
+}, 20_000)
+
+testLinuxTraceFile('graceful shutdown queues otherwise-pending trace records', () => {
+  expect(runFixture({ TRACE_SHUTDOWN_PENDING_ONLY: '1' })).toEqual({
+    aborted: true,
+    exitCalled: true,
+    writeSettled: true,
+    exitObservedSettledWrite: true,
+  })
+}, 20_000)
+
+testLinuxTraceFile('graceful shutdown bounds a blocked interruption trace drain', () => {
+  expect(runFixture({ TRACE_SHUTDOWN_BLOCK_WRITE: '1' })).toEqual({
+    aborted: true,
+    exitCalled: true,
+    writeSettled: false,
+    exitObservedSettledWrite: false,
+  })
+}, 20_000)

src/utils/gracefulShutdown.ts

@@ -39,6 +39,10 @@ import { runCleanupFunctions } from './cleanupRegistry.js'
 import { createCombinedAbortSignal } from './combinedAbortSignal.js'
 import { logForDebugging } from './debug.js'
 import { logForDiagnosticsNoPII } from './diagLogs.js'
+import {
+  flushInterruptionTrace,
+  waitForInterruptionTraceFlush,
+} from './interruptionTrace.js'
 import { isEnvTruthy } from './envUtils.js'
 import { getCurrentSessionTitle, sessionIdExists } from './sessionStorage.js'
 import { sleep } from './sleep.js'
@@ -534,6 +538,12 @@ export async function gracefulShutdown(
     }
   }
 
+  // Root interruption traces are queued off the cancellation path so they
+  // cannot delay abort. Drain that queue before the final process exit; the
+  // drain has its own budget so a blocked target cannot stall normal exit.
+  flushInterruptionTrace('graceful_shutdown')
+  await Promise.race([waitForInterruptionTraceFlush(), sleep(500)])
+
   forceExit(exitCode)
 }
 

src/utils/handlePromptSubmit.test.ts

@@ -7,6 +7,12 @@ import * as realAnalyticsModule from 'src/services/analytics/index.js'
 import { getCommandQueue, resetCommandQueue } from './messageQueueManager.js'
 import { createUserMessage } from './messages.js'
 import * as realProcessUserInputModule from './processUserInput/processUserInput.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from './interruptionTrace.js'
+import type { HandlePromptSubmitParams } from './handlePromptSubmit.js'
 
 const realAnalytics = { ...realAnalyticsModule }
 const realProcessUserInput = { ...realProcessUserInputModule }
@@ -666,4 +672,61 @@ describe('handlePromptSubmit', () => {
       },
     ])
   })
+
+  it('traces the explicit submit-interrupt path at runtime', async () => {
+    const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const controller = new AbortController()
+    const { handlePromptSubmit } = await import('./handlePromptSubmit.js')
+    try {
+      const params: HandlePromptSubmitParams = {
+        input: 'echo ready',
+        mode: 'bash',
+        pastedContents: {},
+        helpers: {
+          setCursorOffset: () => {},
+          clearBuffer: () => {},
+          resetHistory: () => {},
+        },
+        onInputChange: () => {},
+        setPastedContents: () => {},
+        abortController: controller,
+        hasInterruptibleToolInProgress: true,
+        streamMode: 'requesting',
+        queryGuard: { isActive: true } as never,
+        isExternalLoading: false,
+        commands: [],
+        messages: [],
+        mainLoopModel: 'sonnet',
+        ideSelection: undefined,
+        querySource: 'repl' as never,
+        setToolJSX: () => {},
+        getToolUseContext: () => ({}) as never,
+        setUserInputOnProcessing: () => {},
+        setAbortController: () => {},
+        onQuery: async () => {},
+        setAppState: () => ({}) as never,
+      }
+      await handlePromptSubmit(params)
+
+      expect(controller.signal.aborted).toBe(true)
+      const trace = __getInterruptionTraceSnapshotForTests()
+      const inputEvent = trace.find(
+        entry => entry.event === 'input.submit_interrupt',
+      )
+      const abortEvent = trace.find(entry => entry.event === 'abort.requested')
+      expect(abortEvent?.source).toBe('interrupt_on_submit')
+      expect(inputEvent).toBeDefined()
+      expect(abortEvent).toBeDefined()
+      expect(typeof inputEvent!.eventId).toBe('string')
+      expect(typeof abortEvent!.causalEventId).toBe('string')
+      expect(abortEvent!.causalEventId).toBe(inputEvent!.eventId)
+    } finally {
+      await __waitForInterruptionTraceFlushForTests()
+      __resetInterruptionTraceForTests()
+      if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+      else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  })
 })

src/utils/handlePromptSubmit.ts

@@ -24,6 +24,7 @@ import type { EffortValue } from './effort.js'
 import type { FileHistoryState } from './fileHistory.js'
 import { fileHistoryEnabled, fileHistoryMakeSnapshot } from './fileHistory.js'
 import { gracefulShutdownSync } from './gracefulShutdown.js'
+import { requestAbort, traceInterruptionEvent } from './interruptionTrace.js'
 import { enqueue } from './messageQueueManager.js'
 import { resolveSkillModelOverride } from './model/model.js'
 import type { ProcessUserInputContext } from './processUserInput/processUserInput.js'
@@ -376,7 +377,18 @@ export async function handlePromptSubmit(
         streamMode:
           params.streamMode as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
       })
-      params.abortController?.abort('interrupt')
+      if (params.abortController) {
+        const causalEventId = traceInterruptionEvent('input.submit_interrupt', {
+          source: 'interrupt_on_submit',
+          subsystem: 'prompt_submit',
+        })
+        requestAbort(params.abortController, 'interrupt', {
+          source: 'interrupt_on_submit',
+          subsystem: 'prompt_submit',
+          controllerRole: 'query-root',
+          causalEventId,
+        })
+      }
     }
 
     // Enqueue with string value + raw pastedContents. Images will be resized

src/utils/interruptionTrace.test.ts

@@ -0,0 +1,923 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import { mkdir, mkdtemp, readFile, rm, stat, symlink, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import * as interruptionTraceModule from './interruptionTrace.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  flushInterruptionTrace,
+  getInterruptionSignalAbortEventId,
+  registerInterruptionController,
+  requestAbort,
+  traceInterruptionEvent,
+} from './interruptionTrace.js'
+import { createCombinedAbortSignal } from './combinedAbortSignal.js'
+import { createChildAbortController } from './abortController.js'
+import { logForDiagnosticsNoPII } from './diagLogs.js'
+import {
+  getFsImplementation,
+  setFsImplementation,
+  type FsOperations,
+} from './fsOperations.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../test/sharedMutationLock.js'
+
+const originalEnabled = process.env.OPENCLAUDE_INTERRUPT_TRACE
+const originalFile = process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE
+const originalDiagnosticsFile = process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+let tempDirectory: string | undefined
+let originalFs: FsOperations
+const testLinuxTraceFile = process.platform === 'linux' ? test : test.skip
+const testPosixSymlink = process.platform === 'win32' ? test.skip : test
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('utils/interruptionTrace.test.ts')
+  originalFs = getFsImplementation()
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
+  delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+  delete process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE
+  delete process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+})
+
+afterEach(async () => {
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
+  setFsImplementation(originalFs)
+  if (originalEnabled === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+  else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalEnabled
+  if (originalFile === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE
+  else process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = originalFile
+  if (originalDiagnosticsFile === undefined) {
+    delete process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+  } else {
+    process.env.CLAUDE_CODE_DIAGNOSTICS_FILE = originalDiagnosticsFile
+  }
+  if (tempDirectory) {
+    await rm(tempDirectory, { recursive: true, force: true })
+    tempDirectory = undefined
+  }
+  releaseSharedMutationLock()
+})
+
+describe('interruptionTrace', () => {
+  test('is a true no-op while disabled and preserves native abort behavior', () => {
+    const controller = new AbortController()
+    registerInterruptionController(controller, { controllerRole: 'root' })
+    traceInterruptionEvent('query.started', { queryId: 'query-1' })
+    requestAbort(controller, 'query-timeout', {
+      source: 'query_guard',
+      controllerRole: 'root',
+    })
+
+    expect(controller.signal.reason).toBe('query-timeout')
+    expect(__getInterruptionTraceSnapshotForTests()).toEqual([])
+  })
+
+  test('correlates controllers and records first-wins plus repeated requests', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const controller = new AbortController()
+    const controllerId = registerInterruptionController(controller, {
+      controllerRole: 'query-root',
+      queryId: 'query-1',
+    })
+
+    requestAbort(controller, 'query-timeout', {
+      source: 'query_guard',
+      queryId: 'query-1',
+    })
+    requestAbort(controller, 'user-cancel', {
+      source: 'cancel_keybinding',
+      queryId: 'query-1',
+    })
+
+    const entries = __getInterruptionTraceSnapshotForTests()
+    const requested = entries.find(entry => entry.event === 'abort.requested')
+    const observed = entries.find(entry => entry.event === 'signal.observed')
+    const repeated = entries.find(entry => entry.event === 'abort.repeated')
+    expect(controller.signal.reason).toBe('query-timeout')
+    expect(requested?.controllerId).toBe(controllerId)
+    expect(requested?.normalizedReason).toBe('query-timeout')
+    expect(requested?.abortStackFingerprint).toMatch(/^[a-f0-9]{16}$/)
+    expect(requested).not.toHaveProperty('abortCallSites')
+    expect(typeof requested?.eventId).toBe('string')
+    expect(typeof observed?.firstAbortEventId).toBe('string')
+    expect(typeof repeated?.firstAbortEventId).toBe('string')
+    expect(observed!.firstAbortEventId).toBe(requested!.eventId)
+    expect(repeated!.firstAbortEventId).toBe(requested!.eventId)
+    expect(repeated?.existingNormalizedReason).toBe('query-timeout')
+    expect(repeated?.attemptedNormalizedReason).toBe('user-abort')
+    expect(repeated?.outcome).toBe('ignored_first_abort_wins')
+    expect(repeated?.repeatedCount).toBe(1)
+  })
+
+  test('links a combined signal abort to the winning parent request', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const parent = new AbortController()
+    registerInterruptionController(parent, {
+      controllerRole: 'query-root',
+    })
+    const combined = createCombinedAbortSignal(parent.signal, {
+      trace: {
+        subsystem: 'trace-test',
+        controllerRole: 'combined',
+      },
+    })
+
+    requestAbort(parent, 'query-timeout', {
+      source: 'query_guard',
+      subsystem: 'trace-test',
+      controllerRole: 'query-root',
+    })
+
+    const requested = __getInterruptionTraceSnapshotForTests().filter(
+      entry => entry.event === 'abort.requested',
+    )
+    expect(combined.signal.reason).toBe('query-timeout')
+    expect(requested).toHaveLength(2)
+    expect(requested[1]?.causalEventId).toBe(requested[0]?.eventId)
+    expect(requested[1]?.winningParentControllerId).toBe(
+      requested[0]?.controllerId,
+    )
+    combined.cleanup()
+  })
+
+  test('assigns a causal event id when a registered signal aborts natively', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const controller = new AbortController()
+    registerInterruptionController(controller, { controllerRole: 'external' })
+
+    controller.abort('external-abort')
+
+    const observed = __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'signal.observed',
+    )
+    expect(observed).toBeDefined()
+    expect(typeof observed?.eventId).toBe('string')
+    expect(getInterruptionSignalAbortEventId(controller.signal)).toBe(
+      observed!.eventId,
+    )
+
+    requestAbort(controller, 'second-abort', {
+      source: 'native-abort-test',
+      controllerRole: 'external',
+    })
+    const repeated = __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'abort.repeated',
+    )
+    expect(repeated).toBeDefined()
+    expect(typeof repeated?.firstAbortEventId).toBe('string')
+    expect(repeated!.firstAbortEventId).toBe(observed!.eventId)
+  })
+
+  test('links a native AbortSignal.any result to its winning parent', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const caller = new AbortController()
+    const deadline = new AbortController()
+    const combined = AbortSignal.any([caller.signal, deadline.signal])
+    interruptionTraceModule.traceCombinedAbortSignal(
+      combined,
+      [caller.signal, deadline.signal], {
+      subsystem: 'native-any-test',
+      controllerRole: 'request-combined',
+      },
+    )
+
+    caller.abort('user-cancel')
+
+    const entries = __getInterruptionTraceSnapshotForTests()
+    const parentObserved = entries.find(
+      entry =>
+        entry.event === 'signal.observed' &&
+        entry.controllerRole === 'combined-parent',
+    )
+    const combinedObserved = entries.find(
+      entry =>
+        entry.event === 'signal.observed' &&
+        entry.controllerRole === 'request-combined',
+    )
+    expect(parentObserved).toBeDefined()
+    expect(combinedObserved).toMatchObject({
+      subsystem: 'native-any-test',
+      causalEventId: parentObserved!.eventId,
+      winningParentControllerId: parentObserved!.controllerId,
+    })
+  })
+
+  test('records permission abort resolution with the input causal edge', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const inputEventId = traceInterruptionEvent('input.ctrl_c')
+
+    interruptionTraceModule.tracePermissionAbortResolution(
+      'ctrl_c',
+      inputEventId,
+      'remote-permission',
+    )
+
+    expect(__getInterruptionTraceSnapshotForTests().at(-1)).toMatchObject({
+      event: 'permission.abort_resolved',
+      source: 'ctrl_c',
+      subsystem: 'remote-permission',
+      causalEventId: inputEventId,
+      outcome: 'denied',
+    })
+  })
+
+  testLinuxTraceFile('observes and flushes a query-root controller already aborted when registered', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let writes = 0
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async () => {
+        writes++
+      },
+    })
+    const controller = new AbortController()
+    controller.abort('external-abort')
+
+    registerInterruptionController(controller, { controllerRole: 'query-root' })
+    await __waitForInterruptionTraceFlushForTests()
+
+    const observed = __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'signal.observed',
+    )
+    expect(observed?.controllerRole).toBe('query-root')
+    expect(getInterruptionSignalAbortEventId(controller.signal)).toBe(
+      observed?.eventId,
+    )
+    expect(writes).toBe(1)
+  })
+
+  testLinuxTraceFile('preserves an established query-root role when creating a child', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let writes = 0
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async () => {
+        writes++
+      },
+    })
+    const parent = new AbortController()
+    registerInterruptionController(parent, {
+      controllerRole: 'query-root',
+      queryId: 'query-root-1',
+      queryGeneration: 3,
+    })
+    createChildAbortController(parent)
+
+    requestAbort(parent, 'user-cancel', {
+      source: 'cancel_keybinding',
+      controllerRole: 'tool',
+    })
+    await __waitForInterruptionTraceFlushForTests()
+
+    const observed = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'signal.observed' &&
+        entry.normalizedReason === 'user-abort',
+    )
+    const requested = __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'abort.requested',
+    )
+    expect(requested).toMatchObject({
+      source: 'cancel_keybinding',
+      controllerRole: 'query-root',
+      queryId: 'query-root-1',
+      queryGeneration: 3,
+    })
+    expect(observed?.controllerRole).toBe('query-root')
+    expect(writes).toBe(1)
+  })
+
+  test('replaces provisional parent and child roles with concrete lifecycle roles', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const parent = new AbortController()
+    const child = createChildAbortController(parent)
+
+    requestAbort(child, 'sibling_error', {
+      source: 'sibling_error',
+      subsystem: 'streaming_tool_executor',
+      controllerRole: 'sibling-tools',
+    })
+    requestAbort(parent, 'task_stop', {
+      source: 'task_stop',
+      subsystem: 'local_agent_task',
+      controllerRole: 'background-agent',
+      subagentId: 'agent-1',
+    })
+
+    const requested = __getInterruptionTraceSnapshotForTests().filter(
+      entry => entry.event === 'abort.requested',
+    )
+    expect(requested).toHaveLength(2)
+    expect(requested[0]).toMatchObject({
+      source: 'sibling_error',
+      controllerRole: 'sibling-tools',
+    })
+    expect(requested[1]).toMatchObject({
+      source: 'task_stop',
+      controllerRole: 'background-agent',
+      subagentId: 'agent-1',
+    })
+    const observed = __getInterruptionTraceSnapshotForTests().filter(
+      entry => entry.event === 'signal.observed',
+    )
+    expect(observed).toHaveLength(2)
+    expect(observed[0]?.controllerRole).toBe('sibling-tools')
+    expect(observed[1]).toMatchObject({
+      controllerRole: 'background-agent',
+      subagentId: 'agent-1',
+    })
+  })
+
+  test('retains a child owner when the parent aborts before a later request', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const parent = new AbortController()
+    const child = createChildAbortController(parent, undefined, {
+      subsystem: 'in_process_teammate',
+      controllerRole: 'subagent-lifecycle',
+      subagentId: 'agent-1',
+    })
+
+    requestAbort(parent, undefined, {
+      source: 'cancel_keybinding',
+      subsystem: 'query_engine',
+      controllerRole: 'query-root',
+    })
+
+    const childObserved = __getInterruptionTraceSnapshotForTests().find(
+      entry =>
+        entry.event === 'signal.observed' &&
+        entry.controllerRole === 'subagent-lifecycle',
+    )
+    expect(child.signal.aborted).toBe(true)
+    expect(childObserved).toMatchObject({
+      subsystem: 'in_process_teammate',
+      controllerRole: 'subagent-lifecycle',
+      subagentId: 'agent-1',
+    })
+  })
+
+  test('throwing abort-reason accessors cannot block native or combined aborts', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const reason = new Proxy(
+      {},
+      {
+        get() {
+          throw new Error('reason getter must stay isolated')
+        },
+      },
+    )
+    const direct = new AbortController()
+    expect(() =>
+      requestAbort(direct, reason, {
+        source: 'throwing-reason-test',
+        controllerRole: 'query-root',
+      }),
+    ).not.toThrow()
+    expect(direct.signal.aborted).toBe(true)
+    expect(direct.signal.reason).toBe(reason)
+
+    const parent = new AbortController()
+    const combined = createCombinedAbortSignal(parent.signal)
+    expect(() => parent.abort(reason)).not.toThrow()
+    expect(combined.signal.aborted).toBe(true)
+    expect(combined.signal.reason).toBe(reason)
+    combined.cleanup()
+  })
+
+  test('does not persist arbitrary custom error names', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const reason = new Error('private reason message')
+    reason.name = 'private customer prompt'
+
+    traceInterruptionEvent('custom.error', { reason, error: reason })
+
+    const serialized = JSON.stringify(__getInterruptionTraceSnapshotForTests())
+    expect(serialized).not.toContain('private customer prompt')
+    expect(serialized).not.toContain('private reason message')
+    const entry = __getInterruptionTraceSnapshotForTests().at(-1)
+    expect(entry?.rawReasonType).toBe('Error:Error')
+    expect(entry?.safeErrorIdentity).toBe('Error')
+  })
+
+  test('preserves only standardized DOMException names', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const standard = new DOMException('private message', 'AbortError')
+    const custom = new DOMException('private message', 'private customer prompt')
+
+    traceInterruptionEvent('standard.dom.error', {
+      reason: standard,
+      error: standard,
+    })
+    traceInterruptionEvent('custom.dom.error', {
+      reason: custom,
+      error: custom,
+    })
+
+    const entries = __getInterruptionTraceSnapshotForTests()
+    expect(entries.at(-2)?.rawReasonType).toBe('DOMException:AbortError')
+    expect(entries.at(-2)?.safeErrorIdentity).toBe('DOMException:AbortError')
+    expect(entries.at(-1)?.rawReasonType).toBe('DOMException')
+    expect(entries.at(-1)?.safeErrorIdentity).toBe('DOMException')
+    expect(JSON.stringify(entries)).not.toContain('private customer prompt')
+    expect(JSON.stringify(entries)).not.toContain('private message')
+  })
+
+  test('keeps only the newest allowlisted records up to capacity', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = 'true'
+    const emitted = __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS + 88
+    for (let index = 0; index < emitted; index++) {
+      traceInterruptionEvent('stream.progress', {
+        rawByteCount: index,
+        // Runtime extras are deliberately ignored by the allowlist boundary.
+        ...({ prompt: 'must-not-appear' } as Record<string, unknown>),
+      })
+    }
+
+    const entries = __getInterruptionTraceSnapshotForTests()
+    expect(entries).toHaveLength(__INTERRUPTION_TRACE_CAPACITY_FOR_TESTS)
+    expect(entries[0]?.sequence).toBe(emitted - __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS + 1)
+    expect(entries.at(-1)?.sequence).toBe(emitted)
+    expect(JSON.stringify(entries)).not.toContain('must-not-appear')
+    expect(JSON.stringify(entries)).not.toContain('prompt')
+  })
+
+  testLinuxTraceFile('flushes valid JSONL once to an explicit absolute path', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-interrupt-trace-'))
+    const traceFile = join(tempDirectory, 'trace.jsonl')
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = traceFile
+
+    traceInterruptionEvent('query.started', {
+      queryId: 'query-1',
+      model: 'gpt-test',
+    })
+    flushInterruptionTrace('test')
+    flushInterruptionTrace('test-repeat')
+    await __waitForInterruptionTraceFlushForTests()
+
+    const lines = (await readFile(traceFile, 'utf8')).trim().split('\n')
+    const entries = lines.map(line => JSON.parse(line) as { event: string })
+    expect(entries.map(entry => entry.event)).toEqual([
+      'query.started',
+      'trace.flush',
+    ])
+  })
+
+  testLinuxTraceFile('flushes every pending record when the ring is at capacity', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-interrupt-trace-'))
+    const traceFile = join(tempDirectory, 'trace.jsonl')
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = traceFile
+    for (let index = 0; index < __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS; index++) {
+      traceInterruptionEvent('stream.progress', { rawByteCount: index })
+    }
+
+    flushInterruptionTrace('capacity')
+    await __waitForInterruptionTraceFlushForTests()
+
+    const entries = (await readFile(traceFile, 'utf8'))
+      .trim()
+      .split('\n')
+      .map(line => JSON.parse(line) as { sequence: number; event: string })
+    expect(entries).toHaveLength(__INTERRUPTION_TRACE_CAPACITY_FOR_TESTS + 1)
+    expect(entries[0]?.sequence).toBe(1)
+    expect(entries.at(-1)?.event).toBe('trace.flush')
+  })
+
+  testLinuxTraceFile('retains pending records after a failed write and retries them', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let failWrites = true
+    let writeAttempts = 0
+    const successfulWrites: string[] = []
+    setFsImplementation({
+      ...originalFs,
+      mkdirSync: () => {},
+      appendRegularFile: async (_path, data) => {
+        writeAttempts++
+        if (failWrites) throw new Error('synthetic write failure')
+        successfulWrites.push(data)
+      },
+    })
+
+    traceInterruptionEvent('first')
+    flushInterruptionTrace('failed')
+    await __waitForInterruptionTraceFlushForTests()
+    expect(writeAttempts).toBe(1)
+    failWrites = false
+    traceInterruptionEvent('second')
+    flushInterruptionTrace('retry')
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(writeAttempts).toBe(3)
+    expect(successfulWrites).toHaveLength(2)
+    const events = successfulWrites.flatMap(write =>
+      write
+        .trim()
+        .split('\n')
+        .map(line => (JSON.parse(line) as { event: string }).event),
+    )
+    expect(events).toEqual(['first', 'trace.flush', 'second', 'trace.flush'])
+  })
+
+  testLinuxTraceFile('captures the enabled output target before a detached flush starts', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/captured/trace.jsonl'
+    const writes: Array<{ path: string; data: string }> = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (path, data) => {
+        writes.push({ path, data })
+      },
+    })
+
+    traceInterruptionEvent('before_restore')
+    flushInterruptionTrace('captured-target')
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(writes).toHaveLength(1)
+    expect(writes[0]?.path).toBe('/captured/trace.jsonl')
+    expect(writes[0]?.data).toContain('"event":"before_restore"')
+    expect(writes[0]?.data).toContain('"event":"trace.flush"')
+  })
+
+  testLinuxTraceFile('keeps a retry batch bound to its original output target', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/first/trace.jsonl'
+    const writes: Array<{ path: string; data: string }> = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (path, data) => {
+        writes.push({ path, data })
+        if (writes.length === 1) throw new Error('synthetic retryable failure')
+      },
+    })
+
+    traceInterruptionEvent('first_target')
+    flushInterruptionTrace('first')
+    await __waitForInterruptionTraceFlushForTests()
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/second/trace.jsonl'
+    traceInterruptionEvent('second_target')
+    flushInterruptionTrace('second')
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(writes.map(write => write.path)).toEqual([
+      '/first/trace.jsonl',
+      '/first/trace.jsonl',
+      '/second/trace.jsonl',
+    ])
+    expect(writes[1]?.data).toContain('"event":"first_target"')
+    expect(writes[2]?.data).toContain('"event":"second_target"')
+    expect(writes[2]?.data).not.toContain('"event":"first_target"')
+  })
+
+  testLinuxTraceFile('retains an in-flight failed batch outside the bounded ring', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let rejectFirstWrite!: (error: Error) => void
+    let markFirstWriteStarted!: () => void
+    const firstWriteStarted = new Promise<void>(resolve => {
+      markFirstWriteStarted = resolve
+    })
+    const firstWriteBlocked = new Promise<void>((_resolve, reject) => {
+      rejectFirstWrite = reject
+    })
+    const writes: string[] = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (_path, data) => {
+        if (writes.length === 0) {
+          writes.push('failed')
+          markFirstWriteStarted()
+          await firstWriteBlocked
+          return
+        }
+        writes.push(data)
+      },
+    })
+
+    traceInterruptionEvent('must_survive')
+    flushInterruptionTrace('blocked')
+    await firstWriteStarted
+    for (let index = 0; index < __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS + 32; index++) {
+      traceInterruptionEvent('newer', { rawByteCount: index })
+    }
+    rejectFirstWrite(new Error('synthetic write failure'))
+    await __waitForInterruptionTraceFlushForTests()
+    flushInterruptionTrace('retry')
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(writes).toHaveLength(3)
+    expect(writes[1]).toContain('"event":"must_survive"')
+  })
+
+  testLinuxTraceFile('does not replay a batch after an uncertain append failure', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    const writes: string[] = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (_path, data) => {
+        writes.push(data)
+        if (writes.length === 1) {
+          throw Object.assign(new Error('partial append'), {
+            code: 'ERR_DIAGNOSTIC_APPEND_UNCERTAIN',
+          })
+        }
+      },
+    })
+
+    traceInterruptionEvent('first')
+    flushInterruptionTrace('uncertain')
+    await __waitForInterruptionTraceFlushForTests()
+    traceInterruptionEvent('second')
+    flushInterruptionTrace('later')
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(writes).toHaveLength(2)
+    expect(writes[0]).toContain('"event":"first"')
+    expect(writes[1]).not.toContain('"event":"first"')
+    expect(writes[1]).toContain('"event":"second"')
+  })
+
+  testLinuxTraceFile('rejects an existing non-regular trace target', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-interrupt-trace-'))
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = tempDirectory
+    traceInterruptionEvent('pending')
+
+    flushInterruptionTrace('non-regular')
+    await __waitForInterruptionTraceFlushForTests()
+
+    expect(
+      __getInterruptionTraceSnapshotForTests().some(
+        entry => entry.event === 'trace.flush',
+      ),
+    ).toBe(false)
+  })
+
+  testLinuxTraceFile('rejects symlink targets and creates private files and directories', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-interrupt-trace-'))
+    const target = join(tempDirectory, 'target.jsonl')
+    const link = join(tempDirectory, 'trace-link.jsonl')
+    await writeFile(target, '')
+    await symlink(target, link)
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = link
+    traceInterruptionEvent('symlink-pending')
+    flushInterruptionTrace('symlink')
+    await __waitForInterruptionTraceFlushForTests()
+    expect(await readFile(target, 'utf8')).toBe('')
+
+    // The rejected batch remains bound to its original target for retry.
+    // Reset before exercising independent creation and permission behavior.
+    __resetInterruptionTraceForTests()
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+
+    const privateDirectory = join(tempDirectory, 'private')
+    const privateTrace = join(privateDirectory, 'trace.jsonl')
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = privateTrace
+    traceInterruptionEvent('private-target-pending')
+    flushInterruptionTrace('private-target')
+    await __waitForInterruptionTraceFlushForTests()
+    expect((await stat(privateDirectory)).mode & 0o777).toBe(0o700)
+    expect((await stat(privateTrace)).mode & 0o777).toBe(0o600)
+
+    const existingTrace = join(tempDirectory, 'existing.jsonl')
+    await writeFile(existingTrace, '', { mode: 0o644 })
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = existingTrace
+    traceInterruptionEvent('existing-private-target')
+    flushInterruptionTrace('existing-private-target')
+    await __waitForInterruptionTraceFlushForTests()
+    expect((await stat(existingTrace)).mode & 0o777).toBe(0o600)
+  })
+
+  testLinuxTraceFile('rejects a trace target beneath a symlinked parent directory', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-interrupt-trace-'))
+    const realDirectory = join(tempDirectory, 'real-parent')
+    const linkedDirectory = join(tempDirectory, 'linked-parent')
+    const realTrace = join(realDirectory, 'trace.jsonl')
+    await mkdir(realDirectory)
+    await symlink(realDirectory, linkedDirectory, 'dir')
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = join(
+      linkedDirectory,
+      'trace.jsonl',
+    )
+
+    traceInterruptionEvent('symlinked-parent-pending')
+    flushInterruptionTrace('symlinked-parent')
+    await __waitForInterruptionTraceFlushForTests()
+
+    const result = await readFile(realTrace, 'utf8').catch(
+      error => (error as NodeJS.ErrnoException).code,
+    )
+    expect(result).toBe('ENOENT')
+  })
+
+  testPosixSymlink('preserves legacy diagnostics append-through-symlink behavior', async () => {
+    tempDirectory = await mkdtemp(join(tmpdir(), 'openclaude-diagnostics-'))
+    const target = join(tempDirectory, 'target.jsonl')
+    const link = join(tempDirectory, 'diagnostics-link.jsonl')
+    await writeFile(target, '')
+    await symlink(target, link)
+    process.env.CLAUDE_CODE_DIAGNOSTICS_FILE = link
+
+    logForDiagnosticsNoPII('info', 'symlink-test')
+
+    expect(await readFile(target, 'utf8')).toContain('symlink-test')
+    delete process.env.CLAUDE_CODE_DIAGNOSTICS_FILE
+  })
+
+  test('does not block native abort while a trace append is pending', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let releaseWrite!: () => void
+    const writeBlocked = new Promise<void>(resolve => {
+      releaseWrite = resolve
+    })
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async () => writeBlocked,
+    })
+    const controller = new AbortController()
+
+    try {
+      requestAbort(controller, 'user-cancel', {
+        source: 'cancel_keybinding',
+        controllerRole: 'query-root',
+      })
+
+      expect(controller.signal.aborted).toBe(true)
+    } finally {
+      releaseWrite()
+      await __waitForInterruptionTraceFlushForTests()
+    }
+  })
+
+  testLinuxTraceFile('keeps sequence IDs unique and drains later events during an async flush', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    let releaseFirstWrite!: () => void
+    let markFirstWriteStarted!: () => void
+    const firstWriteStarted = new Promise<void>(resolve => {
+      markFirstWriteStarted = resolve
+    })
+    const firstWriteBlocked = new Promise<void>(resolve => {
+      releaseFirstWrite = resolve
+    })
+    const writes: string[] = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (_path, data) => {
+        writes.push(data)
+        if (writes.length === 1) {
+          markFirstWriteStarted()
+          await firstWriteBlocked
+        }
+      },
+    })
+
+    traceInterruptionEvent('before')
+    flushInterruptionTrace('first')
+    try {
+      await firstWriteStarted
+      traceInterruptionEvent('during_one')
+      traceInterruptionEvent('during_two')
+    } finally {
+      releaseFirstWrite()
+      await __waitForInterruptionTraceFlushForTests()
+    }
+    const persistedEvents = writes.flatMap(write =>
+      write
+        .trim()
+        .split('\n')
+        .map(line => (JSON.parse(line) as { event: string }).event),
+    )
+    expect(persistedEvents.filter(event => event === 'before')).toHaveLength(1)
+    expect(persistedEvents.filter(event => event === 'during_one')).toHaveLength(1)
+    expect(persistedEvents.filter(event => event === 'during_two')).toHaveLength(1)
+    const snapshot = __getInterruptionTraceSnapshotForTests()
+    expect(new Set(snapshot.map(entry => entry.eventId)).size).toBe(snapshot.length)
+    expect(snapshot.map(entry => entry.sequence)).toEqual(
+      [...snapshot.map(entry => entry.sequence)].sort((left, right) => left - right),
+    )
+  })
+
+  test('never persists dynamic function names from abort stacks', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const controller = new AbortController()
+    const customerSpecificHandlerName = () => {
+      requestAbort(controller, 'user-cancel', { source: 'test' })
+    }
+
+    customerSpecificHandlerName()
+
+    const serialized = JSON.stringify(__getInterruptionTraceSnapshotForTests())
+    expect(serialized).not.toContain('customerSpecificHandlerName')
+    expect(serialized).not.toContain('abortCallSites')
+  })
+
+  test('does not write for relative paths and isolates write failures', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    traceInterruptionEvent('query.started')
+
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = 'relative-trace.jsonl'
+    expect(() => flushInterruptionTrace('relative')).not.toThrow()
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/proc/openclaude/trace.jsonl'
+    expect(() => flushInterruptionTrace('unwritable')).not.toThrow()
+    await __waitForInterruptionTraceFlushForTests()
+  })
+
+  test('discards trace-file batches without retrying on unsupported platforms', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    process.env.OPENCLAUDE_INTERRUPT_TRACE_FILE = '/trace.jsonl'
+    const writtenData: string[] = []
+    setFsImplementation({
+      ...originalFs,
+      appendRegularFile: async (_path, data) => {
+        writtenData.push(data)
+      },
+    })
+    const platformDescriptor = Object.getOwnPropertyDescriptor(process, 'platform')
+    Object.defineProperty(process, 'platform', {
+      value: 'darwin',
+      configurable: true,
+    })
+    try {
+      traceInterruptionEvent('pending')
+      flushInterruptionTrace('posix-platform')
+      await __waitForInterruptionTraceFlushForTests()
+      traceInterruptionEvent('later')
+      flushInterruptionTrace('posix-platform-later')
+      await __waitForInterruptionTraceFlushForTests()
+      expect(writtenData).toEqual([])
+    } finally {
+      if (platformDescriptor) {
+        Object.defineProperty(process, 'platform', platformDescriptor)
+      }
+    }
+    if (process.platform === 'linux') {
+      traceInterruptionEvent('after_restore')
+      flushInterruptionTrace('restored-platform')
+      await __waitForInterruptionTraceFlushForTests()
+      expect(writtenData).toHaveLength(1)
+      const restoredWrite = writtenData[0] ?? ''
+      expect(restoredWrite).toContain('"event":"after_restore"')
+      expect(restoredWrite).not.toContain('"event":"pending"')
+      expect(restoredWrite).not.toContain('"event":"later"')
+    }
+  })
+
+  test('redacts secret-shaped values and absolute local paths', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    traceInterruptionEvent('provider.failed', {
+      model: 'AKIA1234567890ABCDEF',
+      providerRoute: 'github_pat_1234567890abcdef',
+      attemptId: '\\\\server\\share\\private',
+      queryId: 'prefix(/srv/private/project)',
+      error: new Error('message content is never serialized'),
+    })
+
+    const serialized = JSON.stringify(__getInterruptionTraceSnapshotForTests())
+    expect(serialized).toContain('[redacted]')
+    expect(serialized).toContain('Error')
+    expect(serialized).not.toContain('AKIA1234567890ABCDEF')
+    expect(serialized).not.toContain('github_pat_1234567890abcdef')
+    expect(serialized).not.toContain('server')
+    expect(serialized).not.toContain('/srv/private/project')
+    expect(serialized).not.toContain('message content')
+  })
+
+  test('never serializes secret-shaped or path-shaped abort reasons', () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    const secretReason = 'github_pat_1234567890abcdef'
+    const pathReason = '/srv/private/project/abort-reason'
+
+    traceInterruptionEvent('abort.requested', { reason: secretReason })
+    traceInterruptionEvent('abort.repeated', {
+      existingReason: pathReason,
+      attemptedReason: secretReason,
+    })
+
+    const snapshot = __getInterruptionTraceSnapshotForTests()
+    const serialized = JSON.stringify(snapshot)
+    expect(snapshot).toHaveLength(2)
+    expect(snapshot[0]?.normalizedReason).toBe('unknown-abort')
+    expect(snapshot[1]?.existingNormalizedReason).toBe('unknown-abort')
+    expect(snapshot[1]?.attemptedNormalizedReason).toBe('unknown-abort')
+    expect(serialized).not.toContain(secretReason)
+    expect(serialized).not.toContain(pathReason)
+  })
+})

src/utils/interruptionTrace.ts

@@ -0,0 +1,790 @@
+import { createHash, randomUUID } from 'node:crypto'
+import { isAbsolute, posix, win32 } from 'node:path'
+import {
+  monitorEventLoopDelay,
+  type IntervalHistogram,
+} from 'node:perf_hooks'
+import { normalizeAbortReason } from './abortReasons.js'
+import { appendDiagnosticsNoPII } from './diagLogs.js'
+import { redactHomePath, redactLikelySecrets } from './redaction.js'
+
+const TRACE_CAPACITY = 512
+export const __INTERRUPTION_TRACE_CAPACITY_FOR_TESTS = TRACE_CAPACITY
+const TRACE_SCHEMA_VERSION = 1
+const TRACE_ENABLED_ENV = 'OPENCLAUDE_INTERRUPT_TRACE'
+const TRACE_FILE_ENV = 'OPENCLAUDE_INTERRUPT_TRACE_FILE'
+
+export type InterruptionTraceFields = {
+  source?: string
+  subsystem?: string
+  phase?: string
+  queryId?: string
+  queryGeneration?: number
+  querySource?: string
+  parentQueryId?: string
+  subagentId?: string
+  providerRoute?: string
+  transport?: string
+  model?: string
+  attemptId?: string
+  controllerRole?: string
+  parentControllerIds?: readonly string[]
+  winningParentControllerId?: string
+  causalEventId?: string
+  trigger?: string
+  outcome?: string
+  reason?: unknown
+  existingReason?: unknown
+  attemptedReason?: unknown
+  error?: unknown
+  elapsedQueryMs?: number
+  sinceLastActivityMs?: number
+  sinceLastRawByteMs?: number
+  sinceLastParsedFrameMs?: number
+  sinceLastYieldMs?: number
+  rawByteCount?: number
+  parsedFrameCount?: number
+  controlFrameCount?: number
+  ignoredFrameCount?: number
+  ignoredParsedFrameCount?: number
+  yieldedEventCount?: number
+  activeApiCallCount?: number
+  activeToolUseCount?: number
+  leaseCount?: number
+  suspendCount?: number
+  repeatedCount?: number
+  eventLoopDelayMaxMs?: number
+  eventLoopDelayMeanMs?: number
+}
+
+type SafeTraceFields = Omit<
+  InterruptionTraceFields,
+  | 'reason'
+  | 'existingReason'
+  | 'attemptedReason'
+  | 'error'
+  | 'parentControllerIds'
+> & {
+  normalizedReason?: string
+  rawReasonType?: string
+  existingNormalizedReason?: string
+  existingRawReasonType?: string
+  attemptedNormalizedReason?: string
+  attemptedRawReasonType?: string
+  safeErrorIdentity?: string
+  parentControllerIds?: string[]
+}
+
+export type InterruptionTraceEntry = SafeTraceFields & {
+  schemaVersion: number
+  sequence: number
+  eventId: string
+  traceSessionId: string
+  timestamp: string
+  monotonicMs: number
+  clockDeltaMs: number
+  event: string
+  controllerId?: string
+  firstAbortEventId?: string
+  abortStackFingerprint?: string
+}
+
+type ControllerTraceState = {
+  id: string
+  firstAbortEventId?: string
+  repeatedCount: number
+  fields: InterruptionTraceFields
+  provisionalRole: boolean
+}
+
+type SignalTraceState = {
+  id: string
+  fields: InterruptionTraceFields
+  getAbortFields?: () => InterruptionTraceFields
+}
+
+let traceSessionId = ''
+let sequence = 0
+let startedWallMs = Date.now()
+let startedMonotonicMs = performance.now()
+let ring: InterruptionTraceEntry[] = []
+let flushedThroughSequence = 0
+let controllerCounter = 0
+let signalCounter = 0
+let controllerStates = new WeakMap<AbortController, ControllerTraceState>()
+let signalIds = new WeakMap<AbortSignal, string>()
+let signalAbortEventIds = new WeakMap<AbortSignal, string>()
+let signalAbortSources = new WeakMap<AbortSignal, string>()
+let signalStates = new WeakMap<AbortSignal, SignalTraceState>()
+let errorCausalEventIds = new WeakMap<object, string>()
+let eventLoopDelay: IntervalHistogram | undefined
+let flushQueue: Promise<void> = Promise.resolve()
+let retryBatch:
+  | {
+      entries: readonly InterruptionTraceEntry[]
+      marker: InterruptionTraceEntry
+      logFile: string
+    }
+  | undefined
+
+function isEnabled(): boolean {
+  const value = process.env[TRACE_ENABLED_ENV]?.toLowerCase()
+  return value === '1' || value === 'true'
+}
+
+export function isInterruptionTraceEnabled(): boolean {
+  return isEnabled()
+}
+
+function safeString(value: unknown): string | undefined {
+  if (typeof value !== 'string' || value.length === 0) return undefined
+  const clipped = value.slice(0, 160)
+  const redacted = redactLikelySecrets(redactHomePath(clipped))
+  if (
+    redacted !== clipped ||
+    posix.isAbsolute(clipped) ||
+    win32.isAbsolute(clipped) ||
+    /(?:^|[^a-z0-9_])(?:[a-z]:[\\/]|[/\\]{1,2})/i.test(clipped)
+  ) {
+    return '[redacted]'
+  }
+  return clipped
+}
+
+function safeEventName(value: string): string {
+  return /^[a-z0-9][a-z0-9._-]{0,79}$/i.test(value) ? value : 'unknown'
+}
+
+function safeFiniteNumber(value: unknown): number | undefined {
+  return typeof value === 'number' && Number.isFinite(value) ? value : undefined
+}
+
+const BUILTIN_ERROR_NAMES = new Set([
+  'AggregateError',
+  'Error',
+  'EvalError',
+  'RangeError',
+  'ReferenceError',
+  'SyntaxError',
+  'TypeError',
+  'URIError',
+])
+
+const STANDARD_DOM_EXCEPTION_NAMES = new Set([
+  'AbortError',
+  'DataCloneError',
+  'DataError',
+  'EncodingError',
+  'HierarchyRequestError',
+  'InUseAttributeError',
+  'IndexSizeError',
+  'InvalidAccessError',
+  'InvalidCharacterError',
+  'InvalidModificationError',
+  'InvalidNodeTypeError',
+  'InvalidStateError',
+  'NamespaceError',
+  'NetworkError',
+  'NoDataAllowedError',
+  'NoModificationAllowedError',
+  'NotAllowedError',
+  'NotFoundError',
+  'NotReadableError',
+  'NotSupportedError',
+  'OperationError',
+  'QuotaExceededError',
+  'ReadOnlyError',
+  'SecurityError',
+  'TimeoutError',
+  'TransactionInactiveError',
+  'UnknownError',
+  'URLMismatchError',
+  'VersionError',
+  'WrongDocumentError',
+])
+
+function getSafeErrorName(error: Error): string {
+  if (error instanceof DOMException) {
+    return STANDARD_DOM_EXCEPTION_NAMES.has(error.name)
+      ? `DOMException:${error.name}`
+      : 'DOMException'
+  }
+  return BUILTIN_ERROR_NAMES.has(error.name) ? error.name : 'Error'
+}
+
+function getRawReasonType(reason: unknown): string {
+  if (reason === null) return 'null'
+  if (reason instanceof DOMException) return getSafeErrorName(reason)
+  if (reason instanceof Error) return `Error:${getSafeErrorName(reason)}`
+  if (Array.isArray(reason)) return 'array'
+  return typeof reason
+}
+
+function getSafeErrorIdentity(error: unknown): string | undefined {
+  if (error instanceof Error) return getSafeErrorName(error)
+  return error === undefined ? undefined : typeof error
+}
+
+function toSafeFields(fields: InterruptionTraceFields): SafeTraceFields {
+  const reason = fields.reason
+  const safe: SafeTraceFields = {}
+  const stringFields = [
+    'source',
+    'subsystem',
+    'phase',
+    'queryId',
+    'querySource',
+    'parentQueryId',
+    'subagentId',
+    'providerRoute',
+    'transport',
+    'model',
+    'attemptId',
+    'controllerRole',
+    'winningParentControllerId',
+    'causalEventId',
+    'trigger',
+    'outcome',
+  ] as const
+  for (const key of stringFields) {
+    const value = safeString(fields[key])
+    if (value !== undefined) safe[key] = value
+  }
+  const numberFields = [
+    'queryGeneration',
+    'elapsedQueryMs',
+    'sinceLastActivityMs',
+    'sinceLastRawByteMs',
+    'sinceLastParsedFrameMs',
+    'sinceLastYieldMs',
+    'rawByteCount',
+    'parsedFrameCount',
+    'controlFrameCount',
+    'ignoredFrameCount',
+    'ignoredParsedFrameCount',
+    'yieldedEventCount',
+    'activeApiCallCount',
+    'activeToolUseCount',
+    'leaseCount',
+    'suspendCount',
+    'repeatedCount',
+    'eventLoopDelayMaxMs',
+    'eventLoopDelayMeanMs',
+  ] as const
+  for (const key of numberFields) {
+    const value = safeFiniteNumber(fields[key])
+    if (value !== undefined) safe[key] = value
+  }
+  if (fields.parentControllerIds) {
+    safe.parentControllerIds = fields.parentControllerIds
+      .map(safeString)
+      .filter((value): value is string => value !== undefined)
+      .slice(0, 4)
+  }
+  if (reason !== undefined) {
+    safe.normalizedReason = safeString(normalizeAbortReason(reason))
+    safe.rawReasonType = getRawReasonType(reason)
+  }
+  if (fields.existingReason !== undefined) {
+    safe.existingNormalizedReason = safeString(
+      normalizeAbortReason(fields.existingReason),
+    )
+    safe.existingRawReasonType = getRawReasonType(fields.existingReason)
+  }
+  if (fields.attemptedReason !== undefined) {
+    safe.attemptedNormalizedReason = safeString(
+      normalizeAbortReason(fields.attemptedReason),
+    )
+    safe.attemptedRawReasonType = getRawReasonType(fields.attemptedReason)
+  }
+  const safeErrorIdentity = getSafeErrorIdentity(fields.error)
+  if (safeErrorIdentity !== undefined) safe.safeErrorIdentity = safeErrorIdentity
+  return safe
+}
+
+function getAbortStackEvidence(): { abortStackFingerprint?: string } {
+  const rawStack = new Error().stack
+  if (!rawStack) return {}
+  const sites = rawStack
+    .split('\n')
+    .slice(2, 7)
+    .map(line => {
+      const functionMatch = line.match(/^\s*at\s+([^\s(]+)/)
+      const candidate = safeString(functionMatch?.[1])
+      return candidate && !/[\\/:]/.test(candidate)
+        ? candidate
+        : '<anonymous>'
+    })
+  const fingerprint = createHash('sha256').update(sites.join('>')).digest('hex').slice(0, 16)
+  return { abortStackFingerprint: fingerprint }
+}
+
+function buildEntry(
+  event: string,
+  fields: InterruptionTraceFields,
+  nextSequence: number,
+  extra: Partial<InterruptionTraceEntry> = {},
+  allowDisabled = false,
+): InterruptionTraceEntry | undefined {
+  if (!allowDisabled && !isEnabled()) return undefined
+  if (!traceSessionId) traceSessionId = randomUUID()
+  if (!eventLoopDelay) {
+    eventLoopDelay = monitorEventLoopDelay({ resolution: 20 })
+    eventLoopDelay.enable()
+  }
+  const monotonicMs = performance.now() - startedMonotonicMs
+  const wallElapsedMs = Date.now() - startedWallMs
+  const entry: InterruptionTraceEntry = {
+    schemaVersion: TRACE_SCHEMA_VERSION,
+    sequence: nextSequence,
+    eventId: `${traceSessionId}:${nextSequence}`,
+    traceSessionId,
+    timestamp: new Date().toISOString(),
+    monotonicMs,
+    clockDeltaMs: wallElapsedMs - monotonicMs,
+    event: safeEventName(event),
+    ...toSafeFields({
+      ...fields,
+      eventLoopDelayMaxMs: Number.isFinite(eventLoopDelay.max)
+        ? eventLoopDelay.max / 1_000_000
+        : 0,
+      eventLoopDelayMeanMs: Number.isFinite(eventLoopDelay.mean)
+        ? eventLoopDelay.mean / 1_000_000
+        : 0,
+    }),
+    ...extra,
+  }
+  return entry
+}
+
+function addEntry(
+  event: string,
+  fields: InterruptionTraceFields,
+  extra: Partial<InterruptionTraceEntry> = {},
+): InterruptionTraceEntry | undefined {
+  if (!isEnabled()) return undefined
+  try {
+    const entry = buildEntry(event, fields, sequence + 1, extra)
+    if (!entry) return undefined
+    sequence = entry.sequence
+    ring.push(entry)
+    if (ring.length > TRACE_CAPACITY) ring = ring.slice(-TRACE_CAPACITY)
+    return entry
+  } catch {
+    // Diagnostics must be total for arbitrary abort reasons and metadata.
+    return undefined
+  }
+}
+
+export function traceInterruptionEvent(
+  event: string,
+  fields: InterruptionTraceFields = {},
+): string | undefined {
+  return addEntry(event, fields)?.eventId
+}
+
+export function setInterruptionErrorCausalEventId(
+  error: unknown,
+  eventId: string | undefined,
+): void {
+  if (
+    eventId &&
+    ((typeof error === 'object' && error !== null) ||
+      typeof error === 'function')
+  ) {
+    errorCausalEventIds.set(error, eventId)
+  }
+}
+
+export function getInterruptionErrorCausalEventId(
+  error: unknown,
+): string | undefined {
+  return (typeof error === 'object' && error !== null) ||
+    typeof error === 'function'
+    ? errorCausalEventIds.get(error)
+    : undefined
+}
+
+export function tracePermissionAbortResolution(
+  source: string | undefined,
+  causalEventId: string | undefined,
+  subsystem: string,
+): string | undefined {
+  return traceInterruptionEvent('permission.abort_resolved', {
+    source: source ?? 'unknown',
+    subsystem,
+    causalEventId,
+    outcome: 'denied',
+  })
+}
+
+export function registerInterruptionController(
+  controller: AbortController,
+  fields: InterruptionTraceFields = {},
+  options: {
+    provisionalRole?: boolean
+    refreshQueryContext?: boolean
+  } = {},
+): string | undefined {
+  if (!isEnabled()) return undefined
+  const existing = controllerStates.get(controller)
+  if (existing) {
+    // Registration metadata describes controller identity. Later callers may
+    // add missing context, but must not relabel an established query root as a
+    // parent/tool/controller role merely because they are observing it there.
+    existing.fields = { ...fields, ...existing.fields }
+    if (
+      existing.provisionalRole &&
+      fields.controllerRole !== undefined &&
+      !options.provisionalRole
+    ) {
+      existing.fields.controllerRole = fields.controllerRole
+      existing.provisionalRole = false
+    }
+    if (options.refreshQueryContext) {
+      existing.fields = {
+        ...existing.fields,
+        ...(fields.queryId !== undefined && { queryId: fields.queryId }),
+        ...(fields.queryGeneration !== undefined && {
+          queryGeneration: fields.queryGeneration,
+        }),
+        ...(fields.querySource !== undefined && {
+          querySource: fields.querySource,
+        }),
+        ...(fields.parentQueryId !== undefined && {
+          parentQueryId: fields.parentQueryId,
+        }),
+      }
+    }
+    return existing.id
+  }
+
+  const id = `controller-${++controllerCounter}`
+  controllerStates.set(controller, {
+    id,
+    repeatedCount: 0,
+    fields,
+    provisionalRole: options.provisionalRole === true,
+  })
+  signalIds.set(controller.signal, id)
+  addEntry('controller.registered', fields, { controllerId: id })
+  const observeAbort = () => {
+    const state = controllerStates.get(controller)
+    const observed = addEntry(
+      'signal.observed',
+      { ...state?.fields, reason: controller.signal.reason },
+      {
+        controllerId: id,
+        ...(state?.firstAbortEventId && {
+          firstAbortEventId: state.firstAbortEventId,
+        }),
+      },
+    )
+    if (observed && !signalAbortEventIds.has(controller.signal)) {
+      signalAbortEventIds.set(controller.signal, observed.eventId)
+    }
+    if (
+      observed &&
+      state?.fields.source &&
+      !signalAbortSources.has(controller.signal)
+    ) {
+      signalAbortSources.set(controller.signal, state.fields.source)
+    }
+    if (observed && state && !state.firstAbortEventId) {
+      state.firstAbortEventId = observed.eventId
+    }
+    if (state?.fields.controllerRole === 'query-root') {
+      flushInterruptionTrace('root_abort_observed')
+    }
+  }
+  if (controller.signal.aborted) observeAbort()
+  else controller.signal.addEventListener('abort', observeAbort, { once: true })
+  return id
+}
+
+function preserveControllerIdentity(
+  fields: InterruptionTraceFields,
+  state: ControllerTraceState | undefined,
+): InterruptionTraceFields {
+  const identity = state?.fields
+  if (!identity) return fields
+  return {
+    ...fields,
+    ...(identity.queryId !== undefined && { queryId: identity.queryId }),
+    ...(identity.queryGeneration !== undefined && {
+      queryGeneration: identity.queryGeneration,
+    }),
+    ...(identity.querySource !== undefined && {
+      querySource: identity.querySource,
+    }),
+    ...(identity.parentQueryId !== undefined && {
+      parentQueryId: identity.parentQueryId,
+    }),
+    ...(identity.subagentId !== undefined && {
+      subagentId: identity.subagentId,
+    }),
+    ...(identity.controllerRole !== undefined && {
+      controllerRole: identity.controllerRole,
+    }),
+    ...(identity.parentControllerIds !== undefined && {
+      parentControllerIds: identity.parentControllerIds,
+    }),
+  }
+}
+
+export function getInterruptionSignalId(signal: AbortSignal): string | undefined {
+  return isEnabled() ? signalIds.get(signal) : undefined
+}
+
+export function getInterruptionSignalAbortEventId(
+  signal: AbortSignal,
+): string | undefined {
+  return isEnabled() ? signalAbortEventIds.get(signal) : undefined
+}
+
+export function getInterruptionSignalAbortTrace(
+  signal: AbortSignal,
+): { source?: string; causalEventId?: string } {
+  if (!isEnabled()) return {}
+  return {
+    source: signalAbortSources.get(signal),
+    causalEventId: signalAbortEventIds.get(signal),
+  }
+}
+
+export function registerInterruptionSignal(
+  signal: AbortSignal,
+  fields: InterruptionTraceFields = {},
+  getAbortFields?: () => InterruptionTraceFields,
+): string | undefined {
+  if (!isEnabled()) return undefined
+  const existing = signalIds.get(signal)
+  if (existing) return existing
+  const id = `signal-${++signalCounter}`
+  signalIds.set(signal, id)
+  signalStates.set(signal, { id, fields, getAbortFields })
+  addEntry('signal.registered', fields, { controllerId: id })
+  const observeAbort = () => observeRegisteredSignal(signal)
+  if (signal.aborted) observeAbort()
+  else signal.addEventListener('abort', observeAbort, { once: true })
+  return id
+}
+
+function observeRegisteredSignal(signal: AbortSignal): string | undefined {
+  const existingEventId = signalAbortEventIds.get(signal)
+  if (existingEventId) return existingEventId
+  const state = signalStates.get(signal)
+  if (!state) return undefined
+  const observed = addEntry(
+    'signal.observed',
+    { ...state.fields, ...state.getAbortFields?.(), reason: signal.reason },
+    { controllerId: state.id },
+  )
+  if (observed) signalAbortEventIds.set(signal, observed.eventId)
+  return observed?.eventId
+}
+
+export function traceCombinedAbortSignal(
+  combinedSignal: AbortSignal,
+  parents: readonly AbortSignal[],
+  fields: InterruptionTraceFields = {},
+): string | undefined {
+  if (!isEnabled()) return undefined
+  const parentControllerIds = parents
+    .map(parent =>
+      registerInterruptionSignal(parent, {
+        subsystem: fields.subsystem,
+        controllerRole: 'combined-parent',
+      }),
+    )
+    .filter((value): value is string => value !== undefined)
+  return registerInterruptionSignal(
+    combinedSignal,
+    {
+      ...fields,
+      parentControllerIds,
+    },
+    () => {
+      const winner = parents.find(parent => parent.aborted)
+      if (!winner) return {}
+      // AbortSignal.any can abort the combined signal before ordinary listeners
+      // on the winning parent run. Record the parent synchronously here so the
+      // combined observation carries the causal edge on the native path.
+      observeRegisteredSignal(winner)
+      return {
+        winningParentControllerId: getInterruptionSignalId(winner),
+        causalEventId: getInterruptionSignalAbortEventId(winner),
+      }
+    },
+  )
+}
+
+export function requestAbort(
+  controller: AbortController,
+  reason: unknown,
+  fields: InterruptionTraceFields,
+): void {
+  if (!isEnabled()) {
+    controller.abort(reason)
+    return
+  }
+
+  let shouldFlushRoot = fields.controllerRole === 'query-root'
+  try {
+    const controllerId =
+      registerInterruptionController(controller, fields) ?? 'controller-unknown'
+    const state = controllerStates.get(controller)
+    const requestFields = preserveControllerIdentity(fields, state)
+    shouldFlushRoot ||= state?.fields.controllerRole === 'query-root'
+    if (controller.signal.aborted) {
+      if (state) state.repeatedCount++
+      addEntry(
+        'abort.repeated',
+        {
+          ...requestFields,
+          existingReason: controller.signal.reason,
+          attemptedReason: reason,
+          outcome: 'ignored_first_abort_wins',
+          repeatedCount: state?.repeatedCount ?? 1,
+        },
+        {
+          controllerId,
+          ...(state?.firstAbortEventId && {
+            firstAbortEventId: state.firstAbortEventId,
+          }),
+        },
+      )
+    } else {
+      const entry = addEntry(
+        'abort.requested',
+        { ...requestFields, reason },
+        { controllerId, ...getAbortStackEvidence() },
+      )
+      if (entry && state) {
+        state.firstAbortEventId = entry.eventId
+        signalAbortEventIds.set(controller.signal, entry.eventId)
+        if (fields.source) {
+          signalAbortSources.set(controller.signal, fields.source)
+        }
+      }
+    }
+  } catch {
+    // Best-effort diagnostics must never interfere with the native abort.
+  } finally {
+    controller.abort(reason)
+  }
+  if (shouldFlushRoot) flushInterruptionTrace('root_abort_observed')
+}
+
+export function traceCombinedSignal(
+  combinedController: AbortController,
+  parents: readonly (AbortSignal | undefined)[],
+  fields: InterruptionTraceFields = {},
+): string | undefined {
+  if (!isEnabled()) return undefined
+  const parentControllerIds = parents
+    .map(parent =>
+      parent
+        ? registerInterruptionSignal(parent, {
+            subsystem: fields.subsystem,
+            controllerRole: 'combined-parent',
+          })
+        : undefined,
+    )
+    .filter((value): value is string => value !== undefined)
+  return registerInterruptionController(combinedController, {
+    ...fields,
+    parentControllerIds,
+  })
+}
+
+async function performInterruptionTraceFlush(
+  trigger: string,
+  logFile: string,
+): Promise<void> {
+  try {
+    while (true) {
+      let batch = retryBatch
+      if (!batch) {
+        const pending = ring.filter(
+          entry => entry.sequence > flushedThroughSequence,
+        )
+        if (pending.length === 0) return
+        const marker = buildEntry(
+          'trace.flush',
+          { trigger, repeatedCount: pending.length },
+          sequence + 1,
+          {},
+          true,
+        )
+        if (!marker) return
+        // Reserve the marker before awaiting. Later events get larger IDs, and
+        // this immutable batch remains reachable even if the ring wraps.
+        sequence = marker.sequence
+        batch = { entries: [...pending, marker], marker, logFile }
+      }
+
+      const result = await appendDiagnosticsNoPII(batch.logFile, batch.entries)
+      if (result === 'retryable_failure') {
+        retryBatch = batch
+        return
+      }
+
+      retryBatch = undefined
+      flushedThroughSequence = batch.marker.sequence
+      if (result === 'committed') {
+        ring = [...ring, batch.marker]
+          .sort((left, right) => left.sequence - right.sequence)
+          .slice(-TRACE_CAPACITY)
+      }
+      // Keep draining: events can be recorded while an append is in flight,
+      // including during graceful shutdown after the caller requested a flush.
+    }
+  } catch {
+    // A trace flush is never allowed to affect request cleanup.
+  }
+}
+
+export function flushInterruptionTrace(trigger: string): void {
+  if (!isEnabled()) return
+  const logFile = process.env[TRACE_FILE_ENV]
+  if (!logFile || !isAbsolute(logFile)) return
+  flushQueue = flushQueue
+    .then(() => performInterruptionTraceFlush(trigger, logFile))
+    .catch(() => {
+      // Diagnostics are deliberately detached from request cancellation.
+    })
+}
+
+export async function waitForInterruptionTraceFlush(): Promise<void> {
+  await flushQueue
+}
+
+export async function __waitForInterruptionTraceFlushForTests(): Promise<void> {
+  await waitForInterruptionTraceFlush()
+}
+
+export function __getInterruptionTraceSnapshotForTests(): readonly InterruptionTraceEntry[] {
+  return [...ring]
+}
+
+export function __resetInterruptionTraceForTests(): void {
+  traceSessionId = ''
+  sequence = 0
+  startedWallMs = Date.now()
+  startedMonotonicMs = performance.now()
+  ring = []
+  flushedThroughSequence = 0
+  controllerCounter = 0
+  signalCounter = 0
+  controllerStates = new WeakMap()
+  signalIds = new WeakMap()
+  signalAbortEventIds = new WeakMap()
+  signalAbortSources = new WeakMap()
+  signalStates = new WeakMap()
+  errorCausalEventIds = new WeakMap()
+  retryBatch = undefined
+  flushQueue = Promise.resolve()
+  eventLoopDelay?.disable()
+  eventLoopDelay = undefined
+}

src/utils/permissions/PermissionPromptToolResultSchema.ts

@@ -2,6 +2,7 @@ import type { Tool, ToolUseContext } from 'src/Tool.js'
 import z from 'zod/v4'
 import { logForDebugging } from '../debug.js'
 import { lazySchema } from '../lazySchema.js'
+import { requestAbort } from '../interruptionTrace.js'
 import type {
   PermissionDecision,
   PermissionDecisionReason,
@@ -159,7 +160,11 @@ export async function permissionPromptToolResultToPermissionDecision(
     logForDebugging(
       `SDK permission prompt deny+interrupt: tool=${tool.name} message=${result.message}`,
     )
-    toolUseContext.abortController.abort('interrupt')
+    requestAbort(toolUseContext.abortController, 'interrupt', {
+      source: 'sdk_permission_interrupt',
+      subsystem: 'tool_permission',
+      controllerRole: 'query-root',
+    })
   }
   return {
     ...result,

src/utils/permissions/permissions.headlessPlanHooks.test.ts

@@ -1,4 +1,12 @@
-import { afterAll, beforeAll, describe, expect, mock, test } from 'bun:test'
+import {
+  afterAll,
+  afterEach,
+  beforeAll,
+  describe,
+  expect,
+  mock,
+  test,
+} from 'bun:test'
 import { z } from 'zod/v4'
 import type { ToolPermissionContext, ToolUseContext } from '../../Tool.js'
 import { createToolFixture } from '../../test/toolFixtures.js'
@@ -6,13 +14,15 @@ import {
   acquireSharedMutationLock,
   releaseSharedMutationLock,
 } from '../../test/sharedMutationLock.js'
-import type { PermissionDecision } from './PermissionResult.js'
+import type { PermissionRequestResult } from '../../types/hooks.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from '../interruptionTrace.js'
 import { permissionPromptToolResultToPermissionDecision } from './PermissionPromptToolResultSchema.js'
-import type { PermissionUpdate } from './PermissionUpdateSchema.js'
 
-type HookDecision = PermissionDecision & {
+type HookDecision = PermissionRequestResult
-  updatedPermissions?: PermissionUpdate[]
-}
 
 let hookDecision: HookDecision
 let hasPermissionsToUseTool: typeof import('./permissions.js').hasPermissionsToUseTool
@@ -20,6 +30,7 @@ let createPermissionContext: typeof import('../../hooks/toolPermission/Permissio
 let StructuredIO: typeof import('../../cli/structuredIO.js').StructuredIO
 let actualHooks: typeof import('../hooks.js')
 let beforeHookDecision: (() => void) | undefined
+const originalInterruptionTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
 
 beforeAll(async () => {
   await acquireSharedMutationLock(
@@ -55,6 +66,16 @@ afterAll(() => {
   }
 })
 
+afterEach(async () => {
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
+  if (originalInterruptionTrace === undefined) {
+    delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+  } else {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = originalInterruptionTrace
+  }
+})
+
 function planContext(
   overrides: Partial<ToolPermissionContext> = {},
 ): {
@@ -367,6 +388,82 @@ describe('headless plan-mode PermissionRequest hooks', () => {
     expect(state.getPermissionContext().mode).toBe('plan')
   })
 
+  test('labels SDK permission prompt interrupts as query-root aborts', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const tool = createToolFixture(z.object({}), {
+      name: 'SDKPromptInterruptTool',
+      isReadOnly: () => true,
+    })
+    const state = planContext({ mode: 'default' })
+
+    const result = await permissionPromptToolResultToPermissionDecision(
+      {
+        behavior: 'deny',
+        message: 'Stop the query',
+        interrupt: true,
+      },
+      tool,
+      {},
+      state.context,
+    )
+
+    expect(result.behavior).toBe('deny')
+    expect(state.context.abortController.signal.aborted).toBe(true)
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'sdk_permission_interrupt',
+      ),
+    ).toMatchObject({
+      subsystem: 'tool_permission',
+      controllerRole: 'query-root',
+    })
+  })
+
+  test('labels headless permission hook interrupts as query-root aborts', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const tool = createToolFixture(z.object({}), {
+      name: 'HeadlessHookInterruptTool',
+      isReadOnly: () => true,
+      async checkPermissions() {
+        return { behavior: 'ask' as const, message: 'Review read' }
+      },
+    })
+    const state = planContext({
+      mode: 'default',
+      shouldAvoidPermissionPrompts: true,
+    })
+    hookDecision = {
+      behavior: 'deny',
+      message: 'Stop the query',
+      interrupt: true,
+    }
+
+    const result = await hasPermissionsToUseTool(
+      tool,
+      {},
+      state.context,
+      assistantMessage,
+      'headless-hook-interrupt',
+    )
+
+    expect(result.behavior).toBe('deny')
+    expect(state.context.abortController.signal.aborted).toBe(true)
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'permission_hook',
+      ),
+    ).toMatchObject({
+      subsystem: 'tool_permission',
+      controllerRole: 'query-root',
+    })
+  })
+
   test('SDK permission prompt rechecks plan mode after approval normalization', async () => {
     const conditionalTool = createToolFixture(
       z.object({ operation: z.enum(['read', 'write']) }),
@@ -597,6 +694,47 @@ describe('headless plan-mode PermissionRequest hooks', () => {
     ])
   })
 
+  test('labels interactive permission hook interrupts as query-root aborts', async () => {
+    process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+    __resetInterruptionTraceForTests()
+    const tool = createToolFixture(z.object({}), {
+      name: 'InteractiveHookInterruptTool',
+      isReadOnly: () => true,
+    })
+    const state = planContext({ mode: 'default' })
+    const permissionContext = createPermissionContext(
+      tool,
+      {},
+      state.context,
+      { message: { id: 'assistant-message' } } as never,
+      'interactive-hook-interrupt',
+      state.setPermissionContext,
+    )
+    hookDecision = {
+      behavior: 'deny',
+      message: 'Stop the query',
+      interrupt: true,
+    }
+
+    const result = await permissionContext.runHooks(undefined, undefined)
+
+    expect(result).toMatchObject({
+      behavior: 'deny',
+      message: 'Stop the query',
+    })
+    expect(state.context.abortController.signal.aborted).toBe(true)
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry =>
+          entry.event === 'abort.requested' &&
+          entry.source === 'permission_hook',
+      ),
+    ).toMatchObject({
+      subsystem: 'tool_permission',
+      controllerRole: 'query-root',
+    })
+  })
+
   test('interactive PermissionRequest hooks cannot rewrite a read into a mutation', async () => {
     const conditionalTool = createToolFixture(
       z.object({ operation: z.enum(['read', 'write']) }),

src/utils/permissions/permissions.ts

@@ -25,6 +25,7 @@ import { extractOutputRedirections } from '../bash/commands.js'
 import { logForDebugging } from '../debug.js'
 import { AbortError, toError } from '../errors.js'
 import { logError } from '../log.js'
+import { requestAbort } from '../interruptionTrace.js'
 import { SandboxManager } from '../sandbox/sandbox-adapter.js'
 import {
   getSettingSourceDisplayNameLowercase,
@@ -524,7 +525,11 @@ async function runPermissionRequestHooksForHeadlessAgent(
           logForDebugging(
             `Hook interrupt: tool=${tool.name} hookMessage=${decision.message}`,
           )
-          context.abortController.abort('interrupt')
+          requestAbort(context.abortController, 'interrupt', {
+            source: 'permission_hook',
+            subsystem: 'tool_permission',
+            controllerRole: 'query-root',
+          })
         }
         return {
           behavior: 'deny',

src/utils/queryEventDriver.test.ts

@@ -0,0 +1,79 @@
+import { describe, expect, test } from 'bun:test'
+import { driveQueryEvents } from './queryEventDriver.js'
+
+describe('driveQueryEvents', () => {
+  test('registers activity only for yielded events and returns terminal state', async () => {
+    async function* query(): AsyncGenerator<
+      { type: string },
+      { reason: string }
+    > {
+      yield { type: 'stream_request_start' }
+      yield { type: 'stream_event' }
+      return { reason: 'completed' }
+    }
+    const activity: string[] = []
+    const events: string[] = []
+
+    const terminal = await driveQueryEvents(
+      query(),
+      reason => activity.push(reason),
+      event => events.push(event.type),
+    )
+
+    expect(activity).toEqual([
+      'query_event:stream_request_start',
+      'query_event:stream_event',
+    ])
+    expect(events).toEqual(['stream_request_start', 'stream_event'])
+    expect(terminal).toEqual({ reason: 'completed' })
+  })
+
+  test('closes the generator if event handling throws', async () => {
+    let finalized = false
+    async function* query(): AsyncGenerator<{ type: string }, void> {
+      try {
+        yield { type: 'stream_event' }
+        yield { type: 'must_not_be_seen' }
+      } finally {
+        finalized = true
+      }
+    }
+
+    await expect(
+      driveQueryEvents(
+        query(),
+        () => {},
+        () => {
+          throw new Error('consumer failed')
+        },
+      ),
+    ).rejects.toThrow('consumer failed')
+    expect(finalized).toBe(true)
+  })
+
+  test('does not let generator cleanup mask an event-handler failure', async () => {
+    const generator: AsyncGenerator<{ type: string }, void> = {
+      next: async () => ({ done: false, value: { type: 'stream_event' } }),
+      return: async () => {
+        throw new Error('generator cleanup failed')
+      },
+      throw: async error => {
+        throw error
+      },
+      [Symbol.asyncIterator]() {
+        return this
+      },
+      [Symbol.asyncDispose]: async () => {},
+    }
+
+    await expect(
+      driveQueryEvents(
+        generator,
+        () => {},
+        () => {
+          throw new Error('consumer failed')
+        },
+      ),
+    ).rejects.toThrow('consumer failed')
+  })
+})

src/utils/queryEventDriver.ts

@@ -0,0 +1,30 @@
+/**
+ * Consume a query event generator while preserving the REPL's activity policy:
+ * only events yielded to the consumer count as QueryGuard progress.
+ */
+export async function driveQueryEvents<TEvent extends { type: string }, TReturn>(
+  queryGenerator: AsyncGenerator<TEvent, TReturn>,
+  registerActivity: (reason: string) => void,
+  onEvent: (event: TEvent) => void,
+): Promise<TReturn> {
+  let generatorDone = false
+  try {
+    while (true) {
+      const next = await queryGenerator.next()
+      if (next.done) {
+        generatorDone = true
+        return next.value
+      }
+      registerActivity(`query_event:${next.value.type}`)
+      onEvent(next.value)
+    }
+  } finally {
+    if (!generatorDone) {
+      try {
+        await queryGenerator.return(undefined as never)
+      } catch {
+        // Preserve the generator or event-handler failure that triggered cleanup.
+      }
+    }
+  }
+}

src/utils/queryLifecycle.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from 'vitest'
 import {
   formatQueryLifecycleAbortSignalReason,
   formatQueryLifecycleLogMessage,
+  getQueryTerminalOutcome,
   getQueryTerminalReason,
   type QueryLifecycleContext,
 } from './queryLifecycle.js'
@@ -47,6 +48,13 @@ describe('query lifecycle log formatting', () => {
 })
 
 describe('query terminal reason classification', () => {
+  test('classifies coarse terminal outcomes with abort precedence', () => {
+    expect(getQueryTerminalOutcome({ aborted: false }, false)).toBe('completed')
+    expect(getQueryTerminalOutcome({ aborted: false }, true)).toBe('failed')
+    expect(getQueryTerminalOutcome({ aborted: true }, false)).toBe('aborted')
+    expect(getQueryTerminalOutcome({ aborted: true }, true)).toBe('aborted')
+  })
+
   test('classifies non-aborted completion from throw state', () => {
     expect(
       getQueryTerminalReason({ aborted: false, reason: undefined }, false),

src/utils/queryLifecycle.ts

@@ -13,6 +13,8 @@ export type QueryTerminalReason =
 
 export type QueryGuardTimeoutReason = 'idle' | 'hard_max' | 'lease_expired'
 
+export type QueryTerminalOutcome = 'aborted' | 'failed' | 'completed'
+
 export type QueryActiveApiCall = {
   clientRequestId?: string
   requestId?: string | null
@@ -67,6 +69,7 @@ export type QueryGuardTimeoutInfo = {
   elapsedMs: number
   context: QueryLifecycleContext
   activeOperations: QueryActiveOperationSnapshot
+  causalEventId?: string
 }
 
 export function getQueryTerminalReason(
@@ -93,6 +96,14 @@ export function getQueryTerminalReason(
   }
 }
 
+export function getQueryTerminalOutcome(
+  signal: Pick<AbortSignal, 'aborted'>,
+  didThrow: boolean,
+): QueryTerminalOutcome {
+  if (signal.aborted) return 'aborted'
+  return didThrow ? 'failed' : 'completed'
+}
+
 export function formatQueryLifecycleAbortSignalReason(reason: string): string {
   return `abortSignalReason=${reason}`
 }

src/utils/replInterruption.test.ts

@@ -0,0 +1,79 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+} from './interruptionTrace.js'
+import {
+  requestBackgroundHandoffAbort,
+  requestBridgeInterrupt,
+  requestPriorityNowAbort,
+} from './replInterruption.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+})
+
+afterEach(async () => {
+  await __waitForInterruptionTraceFlushForTests()
+  __resetInterruptionTraceForTests()
+  if (originalTrace === undefined) delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+  else process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+})
+
+describe('REPL interruption source wiring', () => {
+  test('bridge interruption reads the current controller and links its input event', () => {
+    const stale = new AbortController()
+    const current = new AbortController()
+    const ref = { current: stale }
+    ref.current = current
+
+    requestBridgeInterrupt(ref)
+
+    expect(stale.signal.aborted).toBe(false)
+    expect(current.signal.aborted).toBe(true)
+    const trace = __getInterruptionTraceSnapshotForTests()
+    const input = trace.find(entry => entry.event === 'input.bridge_interrupt')
+    const abort = trace.find(entry => entry.event === 'abort.requested')
+    expect(abort?.source).toBe('bridge_interrupt')
+    expect(input).toBeDefined()
+    expect(abort).toBeDefined()
+    expect(typeof input!.eventId).toBe('string')
+    expect(typeof abort!.causalEventId).toBe('string')
+    expect(abort!.causalEventId).toBe(input!.eventId)
+  })
+
+  test('background handoff aborts the foreground query with its source', () => {
+    const controller = new AbortController()
+
+    requestBackgroundHandoffAbort(controller)
+
+    expect(controller.signal.reason).toBe('background')
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'abort.requested',
+      )?.source,
+    ).toBe('background_handoff')
+  })
+
+  test('priority-now reads and aborts the current query controller', () => {
+    const stale = new AbortController()
+    const current = new AbortController()
+    const ref = { current: stale }
+    ref.current = current
+
+    requestPriorityNowAbort(ref)
+
+    expect(stale.signal.aborted).toBe(false)
+    expect(current.signal.reason).toBe('interrupt')
+    expect(
+      __getInterruptionTraceSnapshotForTests().find(
+        entry => entry.event === 'abort.requested',
+      )?.source,
+    ).toBe('priority_now')
+  })
+})

src/utils/replInterruption.ts

@@ -0,0 +1,39 @@
+import { requestAbort, traceInterruptionEvent } from './interruptionTrace.js'
+
+type AbortControllerRef = { readonly current: AbortController | null }
+
+export function requestBridgeInterrupt(ref: AbortControllerRef): void {
+  const controller = ref.current
+  const causalEventId = traceInterruptionEvent('input.bridge_interrupt', {
+    source: 'bridge_interrupt',
+    subsystem: 'repl_bridge',
+  })
+  if (!controller) return
+  requestAbort(controller, 'interrupt', {
+    source: 'bridge_interrupt',
+    subsystem: 'repl_bridge',
+    controllerRole: 'query-root',
+    causalEventId,
+  })
+}
+
+export function requestBackgroundHandoffAbort(
+  controller: AbortController | null,
+): void {
+  if (!controller) return
+  requestAbort(controller, 'background', {
+    source: 'background_handoff',
+    subsystem: 'repl',
+    controllerRole: 'query-root',
+  })
+}
+
+export function requestPriorityNowAbort(ref: AbortControllerRef): void {
+  const controller = ref.current
+  if (!controller) return
+  requestAbort(controller, 'interrupt', {
+    source: 'priority_now',
+    subsystem: 'repl',
+    controllerRole: 'query-root',
+  })
+}

src/utils/swarm/inProcessPermissionAbort.test.ts

@@ -0,0 +1,138 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import type { ToolUseConfirm } from '../../components/permissions/PermissionRequest.js'
+import { getDefaultAppState } from '../../state/AppStateStore.js'
+import type { Tool } from '../../Tool.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+  __waitForInterruptionTraceFlushForTests,
+  requestAbort,
+} from '../interruptionTrace.js'
+import { createInProcessPermissionAbortCompleter } from './inProcessPermissionAbort.js'
+import { createInProcessCanUseTool } from './inProcessRunner.js'
+import {
+  registerLeaderToolUseConfirmQueue,
+  unregisterLeaderToolUseConfirmQueue,
+} from './leaderPermissionBridge.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('inProcessPermissionAbort.test.ts')
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  __resetInterruptionTraceForTests()
+})
+
+afterEach(async () => {
+  try {
+    await __waitForInterruptionTraceFlushForTests()
+    __resetInterruptionTraceForTests()
+    unregisterLeaderToolUseConfirmQueue()
+    if (originalTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+test('links signal-driven permission denial to the winning abort request once', () => {
+  const controller = new AbortController()
+  let deniedCount = 0
+  const completion = createInProcessPermissionAbortCompleter(
+    controller.signal,
+    () => {
+      deniedCount++
+    },
+  )
+
+  requestAbort(controller, undefined, {
+    source: 'query_guard',
+    subsystem: 'query_engine',
+    controllerRole: 'query-root',
+  })
+
+  const trace = __getInterruptionTraceSnapshotForTests()
+  const abortRequest = trace.find(entry => entry.event === 'abort.requested')
+  const permissionResolution = trace.find(
+    entry => entry.event === 'permission.abort_resolved',
+  )
+  expect(deniedCount).toBe(1)
+  expect(abortRequest?.eventId).toBeString()
+  expect(permissionResolution).toMatchObject({
+    source: 'query_guard',
+    subsystem: 'in_process_permission_bridge',
+    outcome: 'denied',
+    causalEventId: abortRequest?.eventId,
+  })
+  expect(completion.completeAbort('ui_cancel', 'later-event')).toBe(false)
+  expect(deniedCount).toBe(1)
+})
+
+test('aborts a queued in-process permission through the production signal path', async () => {
+  const controller = new AbortController()
+  let queue: ToolUseConfirm[] = []
+  registerLeaderToolUseConfirmQueue(updater => {
+    queue = updater(queue)
+  })
+  const canUseTool = createInProcessCanUseTool(
+    {
+      agentId: 'worker-1',
+      agentName: 'worker',
+      teamName: 'test-team',
+      planModeRequired: false,
+      parentSessionId: 'parent-session',
+    },
+    controller,
+  )
+  const appState = getDefaultAppState()
+  const decisionPromise = canUseTool(
+    {
+      name: 'TraceTestTool',
+      description: async () => 'test permission',
+    } as unknown as Tool,
+    {},
+    {
+      getAppState: () => appState,
+      options: {
+        isNonInteractiveSession: false,
+        tools: [],
+      },
+    } as never,
+    {} as never,
+    'tool-use-1',
+    { behavior: 'ask', message: 'approval required' },
+  )
+
+  for (let attempt = 0; attempt < 10 && queue.length === 0; attempt++) {
+    await Promise.resolve()
+  }
+  expect(queue).toHaveLength(1)
+
+  requestAbort(controller, undefined, {
+    source: 'query_guard',
+    subsystem: 'query_engine',
+    controllerRole: 'query-root',
+  })
+
+  await expect(decisionPromise).resolves.toMatchObject({
+    behavior: 'ask',
+  })
+  expect(queue).toHaveLength(0)
+  const trace = __getInterruptionTraceSnapshotForTests()
+  const abortRequest = trace.find(entry => entry.event === 'abort.requested')
+  expect(
+    trace.find(entry => entry.event === 'permission.abort_resolved'),
+  ).toMatchObject({
+    source: 'query_guard',
+    subsystem: 'in_process_permission_bridge',
+    outcome: 'denied',
+    causalEventId: abortRequest?.eventId,
+  })
+})

src/utils/swarm/inProcessPermissionAbort.ts

@@ -0,0 +1,61 @@
+import {
+  getInterruptionSignalAbortTrace,
+  tracePermissionAbortResolution,
+} from '../interruptionTrace.js'
+
+export type InProcessPermissionAbortCompleter = {
+  claim(): boolean
+  completeAbort(
+    source: string | undefined,
+    causalEventId: string | undefined,
+  ): boolean
+  completeSignalAbort(): boolean
+  isSettled(): boolean
+}
+
+export function createInProcessPermissionAbortCompleter(
+  signal: AbortSignal,
+  onAbortSettled: () => void,
+): InProcessPermissionAbortCompleter {
+  let settled = false
+
+  const claim = (): boolean => {
+    if (settled) return false
+    settled = true
+    signal.removeEventListener('abort', onSignalAbort)
+    return true
+  }
+
+  const completeAbort = (
+    source: string | undefined,
+    causalEventId: string | undefined,
+  ): boolean => {
+    if (!claim()) return false
+    tracePermissionAbortResolution(
+      source,
+      causalEventId,
+      'in_process_permission_bridge',
+    )
+    onAbortSettled()
+    return true
+  }
+
+  const completeSignalAbort = (): boolean => {
+    const trace = getInterruptionSignalAbortTrace(signal)
+    return completeAbort(trace.source, trace.causalEventId)
+  }
+
+  const onSignalAbort = () => {
+    completeSignalAbort()
+  }
+
+  signal.addEventListener('abort', onSignalAbort, { once: true })
+  if (signal.aborted) onSignalAbort()
+
+  return {
+    claim,
+    completeAbort,
+    completeSignalAbort,
+    isSettled: () => settled,
+  }
+}

src/utils/swarm/inProcessRunner.ts

@@ -49,6 +49,9 @@ import {
 } from '../../tasks/LocalAgentTask/LocalAgentTask.js'
 import type { CustomAgentDefinition } from '../../tools/AgentTool/loadAgentsDir.js'
 import { runAgent } from '../../tools/AgentTool/runAgent.js'
+import {
+  registerInterruptionController,
+} from '../interruptionTrace.js'
 import { awaitClassifierAutoApproval } from '../../tools/BashTool/bashPermissions.js'
 import { BASH_TOOL_NAME } from '../../tools/BashTool/toolName.js'
 import { SEND_MESSAGE_TOOL_NAME } from '../../tools/SendMessageTool/constants.js'
@@ -126,6 +129,7 @@ import {
   sendPermissionRequestViaMailbox,
 } from './permissionSync.js'
 import { TEAMMATE_SYSTEM_PROMPT_ADDENDUM } from './teammatePromptAddendum.js'
+import { createInProcessPermissionAbortCompleter } from './inProcessPermissionAbort.js'
 
 type SetAppStateFn = (updater: (prev: AppState) => AppState) => void
 
@@ -143,7 +147,7 @@ const PERMISSION_POLL_INTERVAL_MS = 500
  * sends a permission request to the leader's inbox, waits for the response
  * in the teammate's own mailbox.
  */
-function createInProcessCanUseTool(
+export function createInProcessCanUseTool(
   identity: TeammateIdentity,
   abortController: AbortController,
   onPermissionWaitMs?: (waitMs: number) => void,
@@ -259,7 +263,6 @@ function createInProcessCanUseTool(
     // Standard path: use ToolUseConfirm dialog with worker badge
     if (setToolUseConfirmQueue) {
       return new Promise<PermissionDecision>(resolve => {
-        let decisionMade = false
         const permissionStartMs = Date.now()
 
         // Report permission wait time to the caller so it can be
@@ -268,19 +271,20 @@ function createInProcessCanUseTool(
           onPermissionWaitMs?.(Date.now() - permissionStartMs)
         }
 
-        const onAbortListener = () => {
+        const completion = createInProcessPermissionAbortCompleter(
-          if (decisionMade) return
+          abortController.signal,
-          decisionMade = true
+          () => {
             reportPermissionWait()
             resolve({ behavior: 'ask', message: SUBAGENT_REJECT_MESSAGE })
             setToolUseConfirmQueue(queue =>
               queue.filter(item => item.toolUseID !== toolUseID),
             )
-        }
+          },
+        )
 
-        abortController.signal.addEventListener('abort', onAbortListener, {
+        if (completion.isSettled()) {
-          once: true,
+          return
-        })
+        }
 
         setToolUseConfirmQueue(queue => [
           ...queue,
@@ -299,15 +303,8 @@ function createInProcessCanUseTool(
             onUserInteraction() {
               // No-op for teammates (no classifier auto-approval)
             },
-            onAbort() {
+            onAbort(source, causalEventId) {
-              if (decisionMade) return
+              completion.completeAbort(source, causalEventId)
-              decisionMade = true
-              abortController.signal.removeEventListener(
-                'abort',
-                onAbortListener,
-              )
-              reportPermissionWait()
-              resolve({ behavior: 'ask', message: SUBAGENT_REJECT_MESSAGE })
             },
             async onAllow(
               updatedInput: Record<string, unknown>,
@@ -315,12 +312,7 @@ function createInProcessCanUseTool(
               feedback?: string,
               contentBlocks?: ContentBlockParam[],
             ) {
-              if (decisionMade) return
+              if (!completion.claim()) return
-              decisionMade = true
-              abortController.signal.removeEventListener(
-                'abort',
-                onAbortListener,
-              )
               reportPermissionWait()
               const approval = await guardExternalApproval(
                 updatedInput,
@@ -365,12 +357,7 @@ function createInProcessCanUseTool(
               })
             },
             onReject(feedback?: string, contentBlocks?: ContentBlockParam[]) {
-              if (decisionMade) return
+              if (!completion.claim()) return
-              decisionMade = true
-              abortController.signal.removeEventListener(
-                'abort',
-                onAbortListener,
-              )
               reportPermissionWait()
               const message = feedback
                 ? `${SUBAGENT_REJECT_MESSAGE_WITH_REASON_PREFIX}${feedback}`
@@ -378,7 +365,7 @@ function createInProcessCanUseTool(
               resolve({ behavior: 'ask', message, contentBlocks })
             },
             async recheckPermission() {
-              if (decisionMade) return
+              if (completion.isSettled()) return
               const freshResult = await hasPermissionsToUseTool(
                 tool,
                 input,
@@ -386,12 +373,10 @@ function createInProcessCanUseTool(
                 assistantMessage,
                 toolUseID,
               )
-              if (freshResult.behavior === 'allow') {
+              if (
-                decisionMade = true
+                freshResult.behavior === 'allow' &&
-                abortController.signal.removeEventListener(
+                completion.claim()
-                  'abort',
+              ) {
-                  onAbortListener,
-                )
                 reportPermissionWait()
                 setToolUseConfirmQueue(queue =>
                   queue.filter(item => item.toolUseID !== toolUseID),
@@ -421,6 +406,26 @@ function createInProcessCanUseTool(
         workerColor: identity.color,
         teamName: identity.teamName,
       })
+      let pollInterval: ReturnType<typeof setInterval> | undefined
+
+      function cleanup() {
+        if (pollInterval !== undefined) {
+          clearInterval(pollInterval)
+        }
+        unregisterPermissionCallback(request.id)
+      }
+
+      const completion = createInProcessPermissionAbortCompleter(
+        abortController.signal,
+        () => {
+          cleanup()
+          resolve({ behavior: 'ask', message: SUBAGENT_REJECT_MESSAGE })
+        },
+      )
+
+      if (completion.isSettled()) {
+        return
+      }
 
       // Register callback to be invoked when the leader responds
       registerPermissionCallback({
@@ -432,6 +437,7 @@ function createInProcessCanUseTool(
           _feedback?: string,
           contentBlocks?: ContentBlockParam[],
         ) {
+          if (!completion.claim()) return
           cleanup()
           const finalInput =
             updatedInput && Object.keys(updatedInput).length > 0
@@ -460,6 +466,7 @@ function createInProcessCanUseTool(
           })
         },
         onReject(feedback?: string, contentBlocks?: ContentBlockParam[]) {
+          if (!completion.claim()) return
           cleanup()
           const message = feedback
             ? `${SUBAGENT_REJECT_MESSAGE_WITH_REASON_PREFIX}${feedback}`
@@ -472,11 +479,10 @@ function createInProcessCanUseTool(
       void sendPermissionRequestViaMailbox(request)
 
       // Poll teammate's mailbox for the response
-      const pollInterval = setInterval(
+      pollInterval = setInterval(
-        async (abortController, cleanup, resolve, identity, request) => {
+        async (completion, identity, request) => {
           if (abortController.signal.aborted) {
-            cleanup()
+            completion.completeSignalAbort()
-            resolve({ behavior: 'ask', message: SUBAGENT_REJECT_MESSAGE })
             return
           }
 
@@ -514,27 +520,10 @@ function createInProcessCanUseTool(
           }
         },
         PERMISSION_POLL_INTERVAL_MS,
-        abortController,
+        completion,
-        cleanup,
-        resolve,
         identity,
         request,
       )
-
-      const onAbortListener = () => {
-        cleanup()
-        resolve({ behavior: 'ask', message: SUBAGENT_REJECT_MESSAGE })
-      }
-
-      abortController.signal.addEventListener('abort', onAbortListener, {
-        once: true,
-      })
-
-      function cleanup() {
-        clearInterval(pollInterval)
-        unregisterPermissionCallback(request.id)
-        abortController.signal.removeEventListener('abort', onAbortListener)
-      }
     })
   }
 }
@@ -1168,6 +1157,12 @@ export async function runInProcessTeammate(
       // This allows Escape to stop current work without killing the whole teammate.
       // The lifecycle abortController still kills the whole teammate if needed.
       const currentWorkAbortController = createAbortController()
+      registerInterruptionController(currentWorkAbortController, {
+        subsystem: 'in_process_teammate',
+        controllerRole: 'subagent-turn',
+        subagentId: identity.agentId,
+        querySource: 'agent:custom',
+      })
 
       // Store the work controller in task state so UI can abort it
       updateTaskState(

src/utils/swarm/spawnInProcess.interruptionTrace.test.ts

@@ -0,0 +1,88 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import type { AppState } from '../../state/AppState.js'
+import { getDefaultAppState } from '../../state/AppStateStore.js'
+import type { InProcessTeammateTaskState } from '../../tasks/InProcessTeammateTask/types.js'
+import {
+  __getInterruptionTraceSnapshotForTests,
+  __resetInterruptionTraceForTests,
+} from '../interruptionTrace.js'
+import {
+  acquireSharedMutationLock,
+  releaseSharedMutationLock,
+} from '../../test/sharedMutationLock.js'
+import { killInProcessTeammate } from './spawnInProcess.js'
+
+const originalTrace = process.env.OPENCLAUDE_INTERRUPT_TRACE
+
+beforeEach(async () => {
+  await acquireSharedMutationLock(
+    'utils/swarm/spawnInProcess.interruptionTrace.test.ts',
+  )
+})
+
+afterEach(() => {
+  try {
+    __resetInterruptionTraceForTests()
+    if (originalTrace === undefined) {
+      delete process.env.OPENCLAUDE_INTERRUPT_TRACE
+    } else {
+      process.env.OPENCLAUDE_INTERRUPT_TRACE = originalTrace
+    }
+  } finally {
+    releaseSharedMutationLock()
+  }
+})
+
+test('records the teammate lifecycle source before a kill abort', () => {
+  process.env.OPENCLAUDE_INTERRUPT_TRACE = '1'
+  const abortController = new AbortController()
+  const taskId = 'teammate-task-1'
+  const task = {
+    id: taskId,
+    type: 'in_process_teammate',
+    status: 'running',
+    description: 'test teammate',
+    startTime: Date.now(),
+    outputFile: '/tmp/test-teammate-output',
+    outputOffset: 0,
+    notified: false,
+    identity: {
+      agentId: 'researcher',
+      agentName: 'researcher',
+      teamName: '',
+      planModeRequired: false,
+      parentSessionId: 'parent-session',
+    },
+    prompt: 'test',
+    abortController,
+    awaitingPlanApproval: false,
+    permissionMode: 'default',
+    isIdle: false,
+    shutdownRequested: false,
+    pendingUserMessages: [],
+    lastReportedToolCount: 0,
+    lastReportedTokenCount: 0,
+  } satisfies InProcessTeammateTaskState
+  let state: AppState = {
+    ...getDefaultAppState(),
+    tasks: { [taskId]: task },
+  }
+
+  expect(
+    killInProcessTeammate(taskId, updater => {
+      state = updater(state)
+    }),
+  ).toBe(true)
+
+  expect(abortController.signal.aborted).toBe(true)
+  expect(
+    __getInterruptionTraceSnapshotForTests().find(
+      entry => entry.event === 'abort.requested',
+    ),
+  ).toMatchObject({
+    source: 'task_stop',
+    subsystem: 'in_process_teammate',
+    controllerRole: 'subagent-lifecycle',
+    subagentId: 'researcher',
+  })
+})

src/utils/swarm/spawnInProcess.ts

@@ -27,6 +27,10 @@ import { createAbortController } from '../abortController.js'
 import { formatAgentId } from '../agentId.js'
 import { registerCleanup } from '../cleanupRegistry.js'
 import { logForDebugging } from '../debug.js'
+import {
+  registerInterruptionController,
+  requestAbort,
+} from '../interruptionTrace.js'
 import { emitTaskTerminatedSdk } from '../sdkEventQueue.js'
 import { evictTaskOutput } from '../task/diskOutput.js'
 import {
@@ -44,6 +48,11 @@ import { removeMemberByAgentId } from './teamHelpers.js'
 
 type SetAppStateFn = (updater: (prev: AppState) => AppState) => void
 
+export type InProcessTeammateKillTrace = {
+  source: string
+  causalEventId?: string
+}
+
 /**
  * Minimal context required for spawning an in-process teammate.
  * This is a subset of ToolUseContext - only what spawnInProcessTeammate actually uses.
@@ -120,6 +129,11 @@ export async function spawnInProcessTeammate(
     // Create independent AbortController for this teammate
     // Teammates should not be aborted when the leader's query is interrupted
     const abortController = createAbortController()
+    registerInterruptionController(abortController, {
+      subsystem: 'in_process_teammate',
+      controllerRole: 'subagent-lifecycle',
+      subagentId: agentId,
+    })
 
     // Get parent session ID for transcript correlation
     const parentSessionId = getSessionId()
@@ -182,7 +196,12 @@ export async function spawnInProcessTeammate(
     // Register cleanup handler for graceful shutdown
     const unregisterCleanup = registerCleanup(async () => {
       logForDebugging(`[spawnInProcessTeammate] Cleanup called for ${agentId}`)
-      abortController.abort()
+      requestAbort(abortController, undefined, {
+        source: 'graceful_shutdown',
+        subsystem: 'in_process_teammate',
+        controllerRole: 'subagent-lifecycle',
+        subagentId: agentId,
+      })
       // Task state will be updated by the execution loop when it detects abort
     })
     taskState.unregisterCleanup = unregisterCleanup
@@ -227,6 +246,7 @@ export async function spawnInProcessTeammate(
 export function killInProcessTeammate(
   taskId: string,
   setAppState: SetAppStateFn,
+  trace: InProcessTeammateKillTrace = { source: 'task_stop' },
 ): boolean {
   let killed = false
   let teamName: string | null = null
@@ -253,7 +273,15 @@ export function killInProcessTeammate(
     description = teammateTask.description
 
     // Abort the controller to stop execution
-    teammateTask.abortController?.abort()
+    if (teammateTask.abortController) {
+      requestAbort(teammateTask.abortController, undefined, {
+        source: trace.source,
+        subsystem: 'in_process_teammate',
+        controllerRole: 'subagent-lifecycle',
+        subagentId: teammateTask.identity.agentId,
+        causalEventId: trace.causalEventId,
+      })
+    }
 
     // Call cleanup handler
     teammateTask.unregisterCleanup?.()

tests/sdk/query-lifecycle.test.ts

@@ -128,6 +128,21 @@ describe('Engine lazy-init guard (COR-1)', () => {
     expect(() => q.close()).not.toThrow()
   })
 
+  test('QueryImpl close() aborts its wrapper controller after an engine override', () => {
+    const abortController = new AbortController()
+    const q = query({
+      prompt: 'test',
+      options: { cwd: process.cwd(), abortController },
+    })
+    ;(q as unknown as {
+      setEngine(engine: { interrupt(): void }): void
+    }).setEngine({ interrupt() {} })
+
+    q.close()
+
+    expect(abortController.signal.aborted).toBe(true)
+  })
+
   test('SDKSession getMessages() works after construction', async () => {
     const { unstable_v2_createSession } = await import('../../src/entrypoints/sdk/index.js')
     const session = unstable_v2_createSession({

tests/sdk/sdk-v2-lifecycle.test.ts

@@ -151,6 +151,19 @@ describe('V2: session interrupt', () => {
     expect(() => session.interrupt()).not.toThrow()
   })
 
+  test('session.close() aborts its wrapper controller after an engine override', () => {
+    const abortController = new AbortController()
+    const session = unstable_v2_createSession({
+      cwd: process.cwd(),
+      abortController,
+    })
+    attachMockEngine(session, new MockQueryEngine())
+
+    session.close()
+
+    expect(abortController.signal.aborted).toBe(true)
+  })
+
   test('session with external abortController — abort signal propagates', async () => {
     const ac = new AbortController()
     const session = unstable_v2_createSession({