diff --git a/src/commands/provider/provider.tsx b/src/commands/provider/provider.tsx
index 57f0fdbb2..43069714e 100644
--- a/src/commands/provider/provider.tsx
+++ b/src/commands/provider/provider.tsx
@@ -303,9 +303,21 @@ export function buildCurrentProviderSummary(options?: {
   })
 
   if (effectiveRouteId === 'gemini-vertex') {
-    const vertexMetadata = getProviderPresetUiMetadata('gemini-vertex', processEnv)
-    const location = getGeminiVertexLocation(processEnv)
-    const project = getGeminiVertexProjectId(processEnv)
+    // Mirror getAnthropicClient: when routing purely from the saved profile (no
+    // env flag), the saved profile env supplies the project/model/location and
+    // wins over ambient process defaults. With an explicit env flag, the env
+    // values take precedence (the saved keys only fill gaps).
+    const routedFromProfileOnly =
+      !isEnvTruthy(processEnv.CLAUDE_CODE_USE_GEMINI_VERTEX) &&
+      persisted?.profile === 'gemini-vertex'
+    const vertexEnv = (
+      routedFromProfileOnly
+        ? { ...processEnv, ...persisted?.env }
+        : processEnv
+    ) as NodeJS.ProcessEnv
+    const vertexMetadata = getProviderPresetUiMetadata('gemini-vertex', vertexEnv)
+    const location = getGeminiVertexLocation(vertexEnv)
+    const project = getGeminiVertexProjectId(vertexEnv)
     // Mirror the startup screen: the native client always targets
     // /projects/<project>/locations/<location> and requires a project, so
     // surface a project-required state rather than a project-less endpoint.
@@ -315,7 +327,7 @@ export function buildCurrentProviderSummary(options?: {
     return {
       providerLabel: vertexMetadata.label,
       modelLabel: getSafeDisplayValue(
-        getGeminiVertexModel(processEnv),
+        getGeminiVertexModel(vertexEnv),
         secretSource,
       ),
       endpointLabel: getSafeDisplayValue(endpoint, secretSource),
diff --git a/src/components/StartupScreen.test.ts b/src/components/StartupScreen.test.ts
index 8bfdf75f6..b957a4240 100644
--- a/src/components/StartupScreen.test.ts
+++ b/src/components/StartupScreen.test.ts
@@ -403,4 +403,35 @@ describe('detectProvider — Gemini Vertex endpoint reflects the runtime project
       'https://aiplatform.googleapis.com/v1/projects/alias-project/locations/global',
     )
   })
+
+  test('detects Vertex from a saved active profile with no env flag (profile-only)', () => {
+    // No CLAUDE_CODE_USE_GEMINI_VERTEX: routing comes purely from the saved
+    // active profile, exactly like getAnthropicClient. The profile's project
+    // (stored in baseUrl) and model must drive the startup display instead of
+    // falling through to the default Anthropic/OpenAI branch.
+    const restore = getGlobalConfig()
+    saveGlobalConfig(current => ({
+      ...current,
+      providerProfiles: [
+        {
+          id: 'saved_vertex',
+          name: 'Saved Vertex',
+          provider: 'gemini-vertex',
+          baseUrl: 'saved-proj',
+          model: 'gemini-2.5-pro',
+        },
+      ],
+      activeProviderProfileId: 'saved_vertex',
+    }))
+    try {
+      const result = detectProvider()
+      expect(result.name).toBe('Gemini Vertex')
+      expect(result.model).toBe('gemini-2.5-pro')
+      expect(result.baseUrl).toBe(
+        'https://aiplatform.googleapis.com/v1/projects/saved-proj/locations/global',
+      )
+    } finally {
+      saveGlobalConfig(() => restore)
+    }
+  })
 })
diff --git a/src/components/StartupScreen.ts b/src/components/StartupScreen.ts
index ec886dc8a..39a4983c3 100644
--- a/src/components/StartupScreen.ts
+++ b/src/components/StartupScreen.ts
@@ -24,6 +24,12 @@ import {
 import { BRAND_TAGLINE } from '../constants/brand.js'
 import { getGlobalConfig } from '../utils/config.js'
 import { isEnvTruthy } from '../utils/envUtils.js'
+import { getPrimaryModel } from '../utils/providerModels.js'
+import {
+  geminiVertexProjectFromProfile,
+  getActiveProviderProfile,
+  isGeminiVertexEffectiveProvider,
+} from '../utils/providerProfiles.js'
 import { ANSI_DIM, ANSI_RESET, ansiRgb } from '../utils/terminalAnsi.js'
 import {
   resolveLogoPalette,
@@ -84,22 +90,43 @@ const LOGO_CLAUDE = [
 // ─── Provider detection ───────────────────────────────────────────────────────
 
 export function detectProvider(modelOverride?: string): { name: string; model: string; baseUrl: string; isLocal: boolean } {
-  const useGeminiVertex = isEnvTruthy(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX)
+  // Mirror getAnthropicClient: a saved active gemini-vertex profile routes the
+  // session to Vertex even with no CLAUDE_CODE_USE_GEMINI_VERTEX env flag, so
+  // the startup display must reuse the effective-provider check (env flag OR
+  // saved profile) instead of looking at the raw env flag alone.
+  const activeProfile = getActiveProviderProfile()
+  const useGeminiVertex = isGeminiVertexEffectiveProvider(
+    process.env,
+    activeProfile,
+  )
   const useGemini = isEnvTruthy(process.env.CLAUDE_CODE_USE_GEMINI)
   const useGithub = isEnvTruthy(process.env.CLAUDE_CODE_USE_GITHUB)
   const useOpenAI = isEnvTruthy(process.env.CLAUDE_CODE_USE_OPENAI)
   const useMistral = isEnvTruthy(process.env.CLAUDE_CODE_USE_MISTRAL)
 
   if (useGeminiVertex) {
-    // Use the shared resolvers so this display matches the runtime/provider
-    // summary contract (same default model, location and project-alias chain,
-    // with sanitization) instead of drifting via manual env reads.
+    // When routing purely from the saved profile (no env flag), the profile's
+    // own project (stored in baseUrl) and model win over ambient/default env —
+    // exactly as getAnthropicClient resolves them. Env still wins when the flag
+    // is explicitly set. Use the shared resolvers so this display matches the
+    // runtime/provider contract (default model, location and project-alias
+    // chain, with sanitization) instead of drifting via manual env reads.
+    const routedFromProfileOnly =
+      !isEnvTruthy(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX)
+    const profileProject = routedFromProfileOnly
+      ? geminiVertexProjectFromProfile(activeProfile?.baseUrl)
+      : undefined
+    const profileModel =
+      routedFromProfileOnly && activeProfile?.model
+        ? getPrimaryModel(activeProfile.model)
+        : undefined
     const model =
       modelOverride?.trim() ||
+      profileModel ||
       getGeminiVertexModel(process.env) ||
       DEFAULT_GEMINI_VERTEX_MODEL
     const location = getGeminiVertexLocation(process.env)
-    const project = getGeminiVertexProjectId(process.env)
+    const project = profileProject ?? getGeminiVertexProjectId(process.env)
     // The native client always targets /projects/<project>/locations/<location>
     // and throws when no project resolves. Mirror that contract here: when a
     // project is missing, surface a clear "project required" state instead of a
diff --git a/src/integrations/vendors/gemini-vertex.ts b/src/integrations/vendors/gemini-vertex.ts
index be0d1b7c9..4956f686a 100644
--- a/src/integrations/vendors/gemini-vertex.ts
+++ b/src/integrations/vendors/gemini-vertex.ts
@@ -62,7 +62,10 @@ export default defineVendor({
         contextWindow: 1_048_576,
         maxOutputTokens: 65_536,
       },
-      // Thinking model — available on global endpoint only
+      // Thinking model — available on the global endpoint only. The client
+      // enforces this via isGlobalOnlyVertexModel (utils/geminiAuth.ts): a
+      // regional GEMINI_VERTEX_LOCATION with this model is rejected. Keep the
+      // two in sync.
       {
         id: 'gemini-3.5-flash',
         apiName: 'gemini-3.5-flash',
diff --git a/src/services/api/client.test.ts b/src/services/api/client.test.ts
index 9951e4a17..56209d662 100644
--- a/src/services/api/client.test.ts
+++ b/src/services/api/client.test.ts
@@ -377,7 +377,9 @@ test('routes Gemini Vertex provider requests through the native client', async (
   process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
   process.env.GEMINI_VERTEX_PROJECT = 'project-test-1234'
   process.env.GEMINI_VERTEX_LOCATION = 'us-central1'
-  process.env.GEMINI_VERTEX_MODEL = 'gemini-3.5-flash'
+  // A regional location requires a regionally-available model (gemini-3.5-flash
+  // is global-only and would be rejected — see the dedicated test below).
+  process.env.GEMINI_VERTEX_MODEL = 'gemini-2.5-flash'
   process.env.GEMINI_ACCESS_TOKEN = 'vertex-access-token'
   process.env.OPENAI_MODEL = 'gpt-5.5'
 
@@ -405,18 +407,18 @@ test('routes Gemini Vertex provider requests through the native client', async (
 
   const client = (await getAnthropicClient({
     maxRetries: 0,
-    model: 'gemini-3.5-flash',
+    model: 'gemini-2.5-flash',
   })) as unknown as ShimClient
 
   const response = await client.beta.messages.create({
-    model: 'gemini-3.5-flash',
+    model: 'gemini-2.5-flash',
     messages: [{ role: 'user', content: 'hello' }],
     max_tokens: 64,
     stream: false,
   })
 
   expect(capturedUrl).toBe(
-    'https://us-central1-aiplatform.googleapis.com/v1/projects/project-test-1234/locations/us-central1/publishers/google/models/gemini-3.5-flash:generateContent',
+    'https://us-central1-aiplatform.googleapis.com/v1/projects/project-test-1234/locations/us-central1/publishers/google/models/gemini-2.5-flash:generateContent',
   )
   expect(capturedHeaders?.get('authorization')).toBe('Bearer vertex-access-token')
   expect(capturedHeaders?.get('x-goog-user-project')).toBe('project-test-1234')
@@ -425,10 +427,71 @@ test('routes Gemini Vertex provider requests through the native client', async (
   ])
   expect(response).toMatchObject({
     role: 'assistant',
-    model: 'gemini-3.5-flash',
+    model: 'gemini-2.5-flash',
   })
 })
 
+test('rejects a global-only Vertex model paired with a regional location', async () => {
+  delete process.env.CLAUDE_CODE_USE_OPENAI
+  delete process.env.CLAUDE_CODE_USE_GEMINI
+  delete process.env.CLAUDE_CODE_USE_VERTEX
+  process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
+  process.env.GEMINI_VERTEX_PROJECT = 'project-test-1234'
+  process.env.GEMINI_VERTEX_LOCATION = 'us-central1'
+  // gemini-3.5-flash is served only from the global endpoint, so a regional
+  // location must fail fast instead of building an unusable regional URL.
+  process.env.GEMINI_VERTEX_MODEL = 'gemini-3.5-flash'
+  process.env.GEMINI_ACCESS_TOKEN = 'vertex-access-token'
+
+  await expect(
+    getAnthropicClient({ maxRetries: 0, model: 'gemini-3.5-flash' }),
+  ).rejects.toThrow(/only available on the global endpoint/)
+})
+
+test('allows a global-only Vertex model on the global endpoint', async () => {
+  let capturedUrl: string | undefined
+
+  delete process.env.CLAUDE_CODE_USE_OPENAI
+  delete process.env.CLAUDE_CODE_USE_GEMINI
+  delete process.env.CLAUDE_CODE_USE_VERTEX
+  process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
+  process.env.GEMINI_VERTEX_PROJECT = 'project-test-1234'
+  process.env.GEMINI_VERTEX_LOCATION = 'global'
+  process.env.GEMINI_VERTEX_MODEL = 'gemini-3.5-flash'
+  process.env.GEMINI_ACCESS_TOKEN = 'vertex-access-token'
+
+  globalThis.fetch = (async (input, init) => {
+    capturedUrl =
+      typeof input === 'string'
+        ? input
+        : input instanceof URL
+          ? input.toString()
+          : input.url
+    return new Response(
+      JSON.stringify({
+        candidates: [{ content: { parts: [{ text: 'vertex ok' }] } }],
+      }),
+      { headers: { 'Content-Type': 'application/json' } },
+    )
+  }) as FetchType
+
+  const client = (await getAnthropicClient({
+    maxRetries: 0,
+    model: 'gemini-3.5-flash',
+  })) as unknown as ShimClient
+
+  await client.beta.messages.create({
+    model: 'gemini-3.5-flash',
+    messages: [{ role: 'user', content: 'hello' }],
+    max_tokens: 64,
+    stream: false,
+  })
+
+  expect(capturedUrl).toBe(
+    'https://aiplatform.googleapis.com/v1/projects/project-test-1234/locations/global/publishers/google/models/gemini-3.5-flash:generateContent',
+  )
+})
+
 test('saved-profile-only Vertex prefers the profile project/model over ambient env', async () => {
   let capturedUrl: string | undefined
 
diff --git a/src/services/api/client.ts b/src/services/api/client.ts
index a600746cf..97f527030 100644
--- a/src/services/api/client.ts
+++ b/src/services/api/client.ts
@@ -53,6 +53,7 @@ import {
   getGeminiVertexLocation,
   getGeminiVertexModel,
   getGeminiVertexProjectId,
+  isGlobalOnlyVertexModel,
   resolveGeminiCredential,
   resolveGeminiVertexAuthMode,
 } from '../../utils/geminiAuth.js'
@@ -589,6 +590,14 @@ export async function getAnthropicClient({
     if (!vertexProject) {
       throw new Error('Gemini Vertex project is required via GEMINI_VERTEX_PROJECT or GOOGLE_CLOUD_PROJECT')
     }
+    // Some Vertex models are served only from the global endpoint; routing one
+    // to a regional location builds a URL the model is not available on. Fail
+    // fast with an actionable message instead of issuing a doomed request.
+    if (location !== 'global' && isGlobalOnlyVertexModel(geminiVertexModel)) {
+      throw new Error(
+        `Gemini Vertex model "${geminiVertexModel}" is only available on the global endpoint; set GEMINI_VERTEX_LOCATION=global (currently "${location}") to use it.`,
+      )
+    }
 
     const { createGeminiVertexClient } = await import('./geminiVertexClient.js')
     return createGeminiVertexClient({
diff --git a/src/utils/geminiAuth.ts b/src/utils/geminiAuth.ts
index 82174c3e5..63a9bb90c 100644
--- a/src/utils/geminiAuth.ts
+++ b/src/utils/geminiAuth.ts
@@ -83,6 +83,17 @@ export function getGeminiVertexModel(
   return sanitizeCredential(env.GEMINI_VERTEX_MODEL) ?? DEFAULT_GEMINI_VERTEX_MODEL
 }
 
+// Models Vertex only serves from the global endpoint. Pairing one with a
+// regional GEMINI_VERTEX_LOCATION would build a regional URL the model is not
+// available on, so the client validates this before issuing the request. The
+// catalog (integrations/vendors/gemini-vertex.ts) documents which models are
+// global-only; keep the two in sync.
+const GLOBAL_ONLY_VERTEX_MODELS = new Set(['gemini-3.5-flash'])
+
+export function isGlobalOnlyVertexModel(model: string | undefined): boolean {
+  return model !== undefined && GLOBAL_ONLY_VERTEX_MODELS.has(model.trim())
+}
+
 export function getGeminiAuthMode(
   env: NodeJS.ProcessEnv = process.env,
 ): GeminiAuthMode | undefined {
diff --git a/src/utils/log.errorReportingGate.test.ts b/src/utils/log.errorReportingGate.test.ts
new file mode 100644
index 000000000..b0635e747
--- /dev/null
+++ b/src/utils/log.errorReportingGate.test.ts
@@ -0,0 +1,77 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+import { getGlobalConfig, saveGlobalConfig } from './config.js'
+import { getInMemoryErrors, logError } from './log.js'
+
+// Regression for the privacy gate in logError(): a Gemini Vertex session must
+// get no-error-reporting treatment whether it routes via the env flag OR a
+// saved active profile (effective-provider check), so a saved-profile-only
+// Vertex session does not leak errors to the in-memory/reporting sink.
+describe('logError error-reporting gate — Gemini Vertex effective provider', () => {
+  const PROVIDER_FLAGS = [
+    'CLAUDE_CODE_USE_GEMINI_VERTEX',
+    'CLAUDE_CODE_USE_BEDROCK',
+    'CLAUDE_CODE_USE_VERTEX',
+    'CLAUDE_CODE_USE_FOUNDRY',
+    'CLAUDE_CODE_USE_OPENAI',
+    'CLAUDE_CODE_USE_GEMINI',
+    'CLAUDE_CODE_USE_MISTRAL',
+    'CLAUDE_CODE_USE_GITHUB',
+  ]
+  const savedFlags: Record<string, string | undefined> = {}
+  let restoreConfig: ReturnType<typeof getGlobalConfig>
+
+  beforeEach(() => {
+    for (const flag of PROVIDER_FLAGS) {
+      savedFlags[flag] = process.env[flag]
+      delete process.env[flag]
+    }
+    restoreConfig = getGlobalConfig()
+  })
+
+  afterEach(() => {
+    saveGlobalConfig(() => restoreConfig)
+    for (const flag of PROVIDER_FLAGS) {
+      if (savedFlags[flag] === undefined) {
+        delete process.env[flag]
+      } else {
+        process.env[flag] = savedFlags[flag]
+      }
+    }
+  })
+
+  function recorded(marker: string): boolean {
+    return getInMemoryErrors().some(entry => entry.error.includes(marker))
+  }
+
+  test('records errors when not routing to a cloud provider (control)', () => {
+    saveGlobalConfig(current => ({
+      ...current,
+      providerProfiles: [],
+      activeProviderProfileId: undefined,
+    }))
+    const marker = `gate-control-${Date.now()}`
+    logError(new Error(marker))
+    expect(recorded(marker)).toBe(true)
+  })
+
+  test('suppresses errors for a saved-profile-only Gemini Vertex session', () => {
+    // No CLAUDE_CODE_USE_GEMINI_VERTEX flag — routing comes purely from the
+    // saved active profile, just like getAnthropicClient.
+    saveGlobalConfig(current => ({
+      ...current,
+      providerProfiles: [
+        {
+          id: 'saved_vertex',
+          name: 'Saved Vertex',
+          provider: 'gemini-vertex',
+          baseUrl: 'saved-proj',
+          model: 'gemini-2.5-pro',
+        },
+      ],
+      activeProviderProfileId: 'saved_vertex',
+    }))
+    const marker = `gate-vertex-${Date.now()}`
+    logError(new Error(marker))
+    expect(recorded(marker)).toBe(false)
+  })
+})
diff --git a/src/utils/log.ts b/src/utils/log.ts
index 73a572162..ee55ed8a4 100644
--- a/src/utils/log.ts
+++ b/src/utils/log.ts
@@ -20,6 +20,7 @@ import { stripDisplayTags, stripDisplayTagsAllowEmpty } from './displayTags.js'
 import { isEnvTruthy } from './envUtils.js'
 import { toError } from './errors.js'
 import { isEssentialTrafficOnly } from './privacyLevel.js'
+import { isGeminiVertexEffectiveProvider } from './providerProfiles.js'
 import { jsonParse } from './slowOperations.js'
 
 /**
@@ -167,10 +168,13 @@ export function logError(error: unknown): void {
   try {
     // Check if error reporting should be disabled
     if (
-      // Cloud providers (Bedrock/Vertex/Gemini Vertex/Foundry) always disable features
+      // Cloud providers (Bedrock/Vertex/Gemini Vertex/Foundry) always disable features.
+      // Gemini Vertex uses the effective-provider check so a saved-profile-only
+      // Vertex session (no CLAUDE_CODE_USE_GEMINI_VERTEX flag) gets the same
+      // no-error-reporting treatment as the env-flag route.
       isEnvTruthy(process.env.CLAUDE_CODE_USE_BEDROCK) ||
       isEnvTruthy(process.env.CLAUDE_CODE_USE_VERTEX) ||
-      isEnvTruthy(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX) ||
+      isGeminiVertexEffectiveProvider() ||
       isEnvTruthy(process.env.CLAUDE_CODE_USE_FOUNDRY) ||
       process.env.DISABLE_ERROR_REPORTING ||
       isEssentialTrafficOnly()
diff --git a/src/utils/messages.isNotEmptyMessage.test.ts b/src/utils/messages.isNotEmptyMessage.test.ts
index 9c0bc9f68..99c02bde9 100644
--- a/src/utils/messages.isNotEmptyMessage.test.ts
+++ b/src/utils/messages.isNotEmptyMessage.test.ts
@@ -29,6 +29,34 @@ describe('isNotEmptyMessage malformed-history hardening', () => {
     ).toBe(false)
   })
 
+  test('treats a single typeless content block as empty', () => {
+    // A first block without a string `type` (e.g. `{ foo: 'bar' }`) is not a
+    // real content block, so it must not slip through the non-text branch as
+    // non-empty.
+    expect(
+      isNotEmptyMessage({
+        type: 'user',
+        message: { content: [{ foo: 'bar' }] },
+      } as unknown as Message),
+    ).toBe(false)
+    expect(
+      isNotEmptyMessage({
+        type: 'user',
+        message: { content: [{ type: 123 }] },
+      } as unknown as Message),
+    ).toBe(false)
+  })
+
+  test('still reports a non-empty single non-text block', () => {
+    // A well-formed non-text block (e.g. an image) is still non-empty.
+    expect(
+      isNotEmptyMessage({
+        type: 'user',
+        message: { content: [{ type: 'image', source: {} }] },
+      } as unknown as Message),
+    ).toBe(true)
+  })
+
   test('still reports a non-empty string user message', () => {
     expect(
       isNotEmptyMessage({
diff --git a/src/utils/messages.ts b/src/utils/messages.ts
index d01af02f5..0ff9439c3 100644
--- a/src/utils/messages.ts
+++ b/src/utils/messages.ts
@@ -749,6 +749,12 @@ export function isNotEmptyMessage(message: Message): boolean {
   if (!firstBlock || typeof firstBlock !== 'object') {
     return false
   }
+  // Reject typeless blocks (e.g. `{ foo: 'bar' }`) before the non-text branch:
+  // without a string `type` we can't prove it's a real content block, so it
+  // must not count as non-empty.
+  if (typeof firstBlock.type !== 'string') {
+    return false
+  }
   if (firstBlock.type !== 'text') {
     return true
   }
diff --git a/src/utils/providerProfiles.test.ts b/src/utils/providerProfiles.test.ts
index 919dc74ad..f11991dc9 100644
--- a/src/utils/providerProfiles.test.ts
+++ b/src/utils/providerProfiles.test.ts
@@ -1450,11 +1450,12 @@ describe('applyActiveProviderProfileFromConfig', () => {
     }
   })
 
-  test('does not override Gemini Vertex access-token startup selection with saved profile', async () => {
-    // Maintainer repro: CLAUDE_CODE_USE_GEMINI_VERTEX=1 + GEMINI_ACCESS_TOKEN
-    // (no project) is a concrete access-token selection — hasConcreteProviderSelection
-    // already treats it as such — so hasCompleteProviderSelection must agree and
-    // keep the saved profile from hijacking the explicit env selection.
+  test('applies saved profile over Gemini Vertex access-token env with no project', async () => {
+    // Maintainer repro (round 7): CLAUDE_CODE_USE_GEMINI_VERTEX=1 +
+    // GEMINI_ACCESS_TOKEN with no project is an UNUSABLE Vertex selection — the
+    // native client throws "project is required" because access-token mode
+    // cannot derive a project (only ADC can). A stale token-only shell must not
+    // suppress the saved active profile, so the saved profile is applied.
     const { applyActiveProviderProfileFromConfig } =
       await importFreshProviderProfileModules()
     process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
@@ -1471,20 +1472,17 @@ describe('applyActiveProviderProfileFromConfig', () => {
         activeProviderProfileId: 'saved_openai',
       } as any)
 
-      expect(applied).toBeUndefined()
-      expect(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX).toBe('1')
-      expect(process.env.GEMINI_ACCESS_TOKEN).toBe('ya29.startup-token')
-      expect(process.env.CLAUDE_CODE_USE_OPENAI).toBeUndefined()
-      expect(process.env.OPENAI_MODEL).toBeUndefined()
+      expect(applied?.id).toBe('saved_openai')
+      expect(process.env.OPENAI_MODEL).toBe('gpt-4o')
     } finally {
       delete process.env.CLAUDE_CODE_USE_GEMINI_VERTEX
       delete process.env.GEMINI_ACCESS_TOKEN
     }
   })
 
-  test('does not override Gemini Vertex access-token mode startup selection with saved profile', async () => {
-    // Symmetric to the token case: an explicit GEMINI_VERTEX_AUTH_MODE=access-token
-    // is itself a concrete selection (the token may arrive at request time).
+  test('applies saved profile over Gemini Vertex access-token mode with no project', async () => {
+    // Symmetric to the token case: GEMINI_VERTEX_AUTH_MODE=access-token with no
+    // project is equally unusable, so the saved profile wins.
     const { applyActiveProviderProfileFromConfig } =
       await importFreshProviderProfileModules()
     process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
@@ -1501,16 +1499,47 @@ describe('applyActiveProviderProfileFromConfig', () => {
         activeProviderProfileId: 'saved_openai',
       } as any)
 
-      expect(applied).toBeUndefined()
-      expect(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX).toBe('1')
-      expect(process.env.GEMINI_VERTEX_AUTH_MODE).toBe('access-token')
-      expect(process.env.CLAUDE_CODE_USE_OPENAI).toBeUndefined()
+      expect(applied?.id).toBe('saved_openai')
+      expect(process.env.OPENAI_MODEL).toBe('gpt-4o')
     } finally {
       delete process.env.CLAUDE_CODE_USE_GEMINI_VERTEX
       delete process.env.GEMINI_VERTEX_AUTH_MODE
     }
   })
 
+  test('keeps Gemini Vertex access-token startup selection when a project is set', async () => {
+    // With a project alias the access-token selection is usable, so it stays
+    // and the saved profile must not hijack it.
+    const { applyActiveProviderProfileFromConfig } =
+      await importFreshProviderProfileModules()
+    process.env.CLAUDE_CODE_USE_GEMINI_VERTEX = '1'
+    process.env.GEMINI_ACCESS_TOKEN = 'ya29.startup-token'
+    process.env.GEMINI_VERTEX_PROJECT = 'explicit-project'
+    try {
+      const applied = applyActiveProviderProfileFromConfig({
+        providerProfiles: [
+          buildProfile({
+            id: 'saved_openai',
+            baseUrl: 'https://api.openai.com/v1',
+            model: 'gpt-4o',
+          }),
+        ],
+        activeProviderProfileId: 'saved_openai',
+      } as any)
+
+      expect(applied).toBeUndefined()
+      expect(process.env.CLAUDE_CODE_USE_GEMINI_VERTEX).toBe('1')
+      expect(process.env.GEMINI_ACCESS_TOKEN).toBe('ya29.startup-token')
+      expect(process.env.GEMINI_VERTEX_PROJECT).toBe('explicit-project')
+      expect(process.env.CLAUDE_CODE_USE_OPENAI).toBeUndefined()
+      expect(process.env.OPENAI_MODEL).toBeUndefined()
+    } finally {
+      delete process.env.CLAUDE_CODE_USE_GEMINI_VERTEX
+      delete process.env.GEMINI_ACCESS_TOKEN
+      delete process.env.GEMINI_VERTEX_PROJECT
+    }
+  })
+
   test('applies saved profile when the Gemini Vertex flag is bare (stale export)', async () => {
     // A lone CLAUDE_CODE_USE_GEMINI_VERTEX=1 with no project/model/location
     // is a stale shell export, not intent — same semantics as the other
diff --git a/src/utils/providerProfiles.ts b/src/utils/providerProfiles.ts
index 5be5a5c8a..08d2f3a8d 100644
--- a/src/utils/providerProfiles.ts
+++ b/src/utils/providerProfiles.ts
@@ -501,19 +501,33 @@ function hasCompleteProviderSelection(
     )
   }
   if (processEnv.CLAUDE_CODE_USE_GEMINI_VERTEX !== undefined) {
-    return (
+    // An explicit project alias is enough to route, regardless of auth mode.
+    if (
       trimOrUndefined(processEnv.GEMINI_VERTEX_PROJECT) !== undefined ||
       trimOrUndefined(processEnv.GOOGLE_CLOUD_PROJECT) !== undefined ||
       trimOrUndefined(processEnv.GCLOUD_PROJECT) !== undefined ||
-      trimOrUndefined(processEnv.GOOGLE_PROJECT_ID) !== undefined ||
-      trimOrUndefined(processEnv.GEMINI_VERTEX_MODEL) !== undefined ||
-      trimOrUndefined(processEnv.GEMINI_VERTEX_LOCATION) !== undefined ||
-      trimOrUndefined(processEnv.GEMINI_ACCESS_TOKEN) !== undefined ||
-      trimOrUndefined(processEnv.GOOGLE_APPLICATION_CREDENTIALS) !== undefined ||
-      trimOrUndefined(processEnv.GEMINI_VERTEX_AUTH_MODE)?.toLowerCase() === 'adc' ||
-      trimOrUndefined(processEnv.GEMINI_VERTEX_AUTH_MODE)?.toLowerCase() ===
-        'access-token'
-    )
+      trimOrUndefined(processEnv.GOOGLE_PROJECT_ID) !== undefined
+    ) {
+      return true
+    }
+    // ADC is the only auth mode that can derive a project from the credentials
+    // (getAnthropicClient falls back to credential.projectId for ADC only), so
+    // an ADC selection is complete even without an explicit project alias.
+    const authMode = trimOrUndefined(
+      processEnv.GEMINI_VERTEX_AUTH_MODE,
+    )?.toLowerCase()
+    if (authMode === 'adc') return true
+    if (
+      authMode !== 'access-token' &&
+      trimOrUndefined(processEnv.GOOGLE_APPLICATION_CREDENTIALS) !== undefined
+    ) {
+      return true
+    }
+    // access-token / token-only Vertex selections cannot route without a
+    // project — the native client throws "project is required" — so treating
+    // them as complete would suppress the saved active profile and strand
+    // startup on an unusable Vertex route. Require a project alias here.
+    return false
   }
   if (processEnv.CLAUDE_CODE_USE_GEMINI !== undefined) {
     return (