diff --git a/src/utils/ide.download.test.ts b/src/utils/ide.download.test.ts
new file mode 100644
index 000000000..b090c1096
--- /dev/null
+++ b/src/utils/ide.download.test.ts
@@ -0,0 +1,126 @@
+import { afterEach, beforeEach, expect, spyOn, test } from 'bun:test'
+import axios from 'axios'
+import { existsSync, mkdtempSync, readFileSync, rmSync, type WriteStream } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { Readable } from 'node:stream'
+import { acquireSharedMutationLock, releaseSharedMutationLock } from '../test/sharedMutationLock.js'
+import * as config from './config.js'
+import * as executor from './execFileNoThrow.js'
+import { getFsImplementation, setFsImplementation } from './fsOperations.js'
+import { maybeInstallIDEExtension } from './ide.js'
+
+let originalFs: ReturnType<typeof getFsImplementation>
+let originalUserType: string | undefined
+let originalArtifactory: string | undefined
+let scratch: string
+let downloadedPath: string
+let destination: WriteStream | undefined
+let source: Readable
+let failDestination: boolean
+let getSpy: ReturnType<typeof spyOn<typeof axios, 'get'>>
+let execSpy: ReturnType<typeof spyOn<typeof executor, 'execFileNoThrowWithCwd'>>
+let configSpy: ReturnType<typeof spyOn<typeof config, 'getGlobalConfig'>>
+
+beforeEach(async () => {
+  await acquireSharedMutationLock('ide.download.test.ts')
+  originalFs = getFsImplementation()
+  originalUserType = process.env.USER_TYPE
+  originalArtifactory = process.env.CLAUDE_CODE_INTERNAL_ARTIFACTORY_BASE_URL
+  scratch = mkdtempSync(join(tmpdir(), 'ide-download-'))
+  downloadedPath = ''
+  destination = undefined
+  failDestination = false
+  process.env.USER_TYPE = 'ant'
+  process.env.CLAUDE_CODE_INTERNAL_ARTIFACTORY_BASE_URL = 'https://artifactory.example.test'
+  configSpy = spyOn(config, 'getGlobalConfig').mockReturnValue({ diffTool: 'auto' } as ReturnType<typeof config.getGlobalConfig>)
+  execSpy = spyOn(executor, 'execFileNoThrowWithCwd').mockResolvedValue({ code: 0, stdout: '', stderr: '' })
+  getSpy = spyOn(axios, 'get')
+  setFsImplementation({
+    ...originalFs,
+    readFile: (path, options) => path.endsWith('.npmrc')
+      ? Promise.resolve('//artifactory.example.test/api/npm/npm-all/:_authToken=test-token')
+      : originalFs.readFile(path, options),
+    createWriteStream: path => {
+      downloadedPath = String(path)
+      destination = originalFs.createWriteStream(
+        failDestination ? join(scratch, 'missing', 'extension.vsix') : path,
+      )
+      return destination
+    },
+  })
+})
+
+afterEach(() => {
+  source?.destroy()
+  destination?.destroy()
+  getSpy.mockRestore()
+  execSpy.mockRestore()
+  configSpy.mockRestore()
+  setFsImplementation(originalFs)
+  if (originalUserType === undefined) delete process.env.USER_TYPE
+  else process.env.USER_TYPE = originalUserType
+  if (originalArtifactory === undefined) delete process.env.CLAUDE_CODE_INTERNAL_ARTIFACTORY_BASE_URL
+  else process.env.CLAUDE_CODE_INTERNAL_ARTIFACTORY_BASE_URL = originalArtifactory
+  rmSync(scratch, { recursive: true, force: true })
+  releaseSharedMutationLock()
+})
+
+async function install() {
+  getSpy
+    .mockResolvedValueOnce({ data: '1.2.3' } as Awaited<ReturnType<typeof axios.get>>)
+    .mockResolvedValueOnce({ data: source } as Awaited<ReturnType<typeof axios.get>>)
+  const pending = maybeInstallIDEExtension('vscode')
+  let deadline: ReturnType<typeof setTimeout> | undefined
+  try {
+    return await Promise.race([
+      pending,
+      new Promise<never>((_, reject) => {
+        deadline = setTimeout(() => reject(new Error('installation did not settle after download failure')), 2000)
+      }),
+    ])
+  } finally {
+    clearTimeout(deadline)
+    // Also settle the old, broken implementation when running the regression before the fix.
+    if (destination && !destination.destroyed) destination.destroy(new Error('test teardown'))
+    await pending
+  }
+}
+
+test('reports a failed source download and removes the partial VSIX without installing it', async () => {
+  source = Readable.from((async function* () {
+    yield Buffer.from('partial extension')
+    throw new Error('download interrupted')
+  })())
+  // Keep the baseline implementation from raising an uncaught stream error.
+  // The caller must still report the failure and settle its installation promise.
+  source.on('error', () => {})
+  const result = await install()
+  expect(result).toMatchObject({ installed: false, error: 'download interrupted', installedVersion: null })
+  expect(execSpy).not.toHaveBeenCalled()
+  expect(destination?.closed).toBe(true)
+  expect(existsSync(downloadedPath)).toBe(false)
+})
+
+test('reports destination errors and destroys the source without installing', async () => {
+  source = new Readable({ read() {} })
+  failDestination = true
+  const result = await install()
+  expect(result?.installed).toBe(false)
+  expect(result?.error).toContain('ENOENT')
+  expect(source.destroyed).toBe(true)
+  expect(execSpy).not.toHaveBeenCalled()
+  expect(existsSync(downloadedPath)).toBe(false)
+})
+
+test('installs the complete downloaded VSIX and cleans it up afterward', async () => {
+  source = Readable.from([Buffer.from('complete extension')])
+  execSpy.mockImplementation(async (_command, args) => {
+    expect(readFileSync(args[2]!, 'utf8')).toBe('complete extension')
+    return { code: 0, stdout: '', stderr: '' }
+  })
+  const result = await install()
+  expect(result).toMatchObject({ installed: true, error: null, installedVersion: '1.2.3' })
+  expect(execSpy).toHaveBeenCalledTimes(1)
+  expect(existsSync(downloadedPath)).toBe(false)
+})
diff --git a/src/utils/ide.ts b/src/utils/ide.ts
index 1feab81c1..428ab6027 100644
--- a/src/utils/ide.ts
+++ b/src/utils/ide.ts
@@ -4,6 +4,7 @@ import { execa } from 'execa'
 import capitalize from 'lodash-es/capitalize.js'
 import memoize from 'lodash-es/memoize.js'
 import { createConnection } from 'net'
+import { pipeline } from 'node:stream/promises'
 import * as os from 'os'
 import { basename, join, sep as pathSeparator, resolve } from 'path'
 import { logEvent } from 'src/services/analytics/index.js'
@@ -1465,11 +1466,7 @@ async function installFromArtifactory(command: string): Promise<string> {
 
       // Write the downloaded file to disk
       const writeStream = getFsImplementation().createWriteStream(tempVsixPath)
-      await new Promise<void>((resolve, reject) => {
-        vsixResponse.data.pipe(writeStream)
-        writeStream.on('finish', resolve)
-        writeStream.on('error', reject)
-      })
+      await pipeline(vsixResponse.data, writeStream)
 
       // Install the .vsix file
       // Add delay to prevent code command crashes