diff --git a/src/main/ai-vault/opencode-wsl-runtime-preparation.ts b/src/main/ai-vault/opencode-wsl-runtime-preparation.ts
index 8d01e00072e..36847613265 100644
--- a/src/main/ai-vault/opencode-wsl-runtime-preparation.ts
+++ b/src/main/ai-vault/opencode-wsl-runtime-preparation.ts
@@ -19,6 +19,7 @@ import {
 import { REMOTE_NODE_RUNTIME_READY } from '../ssh/orcad-remote-node-runtime-report'
 import { getRemoteHostPlatform } from '../ssh/ssh-remote-platform'
 import { runWslProcess, type WslSpec } from '../wsl/wsl-runner'
+import { describeWslProcessFailure } from '../wsl/wsl-process-failure'
 import { filterPathsToRunningWslDistrosAsync } from '../wsl-running-path-filter'
 import type { OpenCodeWslRuntime } from './session-scanner-opencode-wsl-runtime'
 
@@ -97,7 +98,7 @@ async function prepare(distro: string): Promise<OpenCodeWslRuntime> {
       maxOutputBytes: 16 * 1024
     })
     if (result.code !== 0 || result.timedOut) {
-      throw new Error(`WSL SQLite reader setup failed: ${result.stderr.trim() || 'command failed'}`)
+      throw new Error(`WSL SQLite reader setup failed: ${describeWslProcessFailure(result)}`)
     }
     return result.stdout.trim()
   }
diff --git a/src/main/claude-accounts/claude-profile-wsl-router.test.ts b/src/main/claude-accounts/claude-profile-wsl-router.test.ts
index b2f755dcd7d..7b4b9556ca5 100644
--- a/src/main/claude-accounts/claude-profile-wsl-router.test.ts
+++ b/src/main/claude-accounts/claude-profile-wsl-router.test.ts
@@ -17,7 +17,12 @@ import type { ClaudeManagedAccount } from '../../shared/managed-account-types'
 import type { WslSpec } from '../wsl/wsl-runner'
 import type * as WslPaths from '../../shared/wsl-paths'
 
-const guest = vi.hoisted(() => ({ home: '' }))
+const guest = vi.hoisted(
+  (): { home: string; failure: { code: number; stdout: string } | null } => ({
+    home: '',
+    failure: null
+  })
+)
 // Emulate the guest with local POSIX paths and /bin/sh.
 vi.mock('../../shared/wsl-paths', async (original) => ({
   ...(await original<typeof WslPaths>()),
@@ -29,6 +34,9 @@ vi.mock('../wsl', () => ({
 }))
 vi.mock('../wsl/wsl-runner', () => ({
   runWslProcess: async (spec: WslSpec) => {
+    if (guest.failure) {
+      return { ...guest.failure, stderr: '', timedOut: false }
+    }
     const result = spawnSync('/bin/sh', ['-c', spec.script ?? '', 'sh', ...(spec.args ?? [])], {
       encoding: 'utf8'
     })
@@ -49,7 +57,10 @@ import { wslClaudeProfile } from './claude-profile-wsl-paths'
 // Guest emulation runs POSIX scripts and the Linux Node bundle.
 const posixHost = process.platform !== 'win32'
 const roots: string[] = []
-afterEach(() => roots.splice(0).forEach((root) => rmSync(root, { recursive: true, force: true })))
+afterEach(() => {
+  guest.failure = null
+  roots.splice(0).forEach((root) => rmSync(root, { recursive: true, force: true }))
+})
 
 function fixture() {
   const root = mkdtempSync(join(tmpdir(), 'claude-wsl-router-'))
@@ -95,6 +106,16 @@ function fixture() {
 }
 
 describe.skipIf(!posixHost)('ClaudeWslProfileRouter', () => {
+  it('names why a silent guest command failed instead of a bare "command failed"', async () => {
+    const f = fixture()
+    guest.failure = { code: 0xffffffff, stdout: 'Wsl/Service/0x80072747\r\n' }
+    await expect(f.router.publish('Ubuntu')).rejects.toThrow(
+      'WSL Ubuntu: wsl.exe: Wsl/Service/0x80072747'
+    )
+    guest.failure = { code: 3, stdout: '' }
+    await expect(f.router.publish('Ubuntu')).rejects.toThrow('WSL Ubuntu: exited with code 3')
+  })
+
   it('publishes and launches the saved account across distro casing without changing guest spelling', async () => {
     const f = fixture()
     await f.router.publish('ubuntu')
diff --git a/src/main/claude-accounts/claude-profile-wsl-router.ts b/src/main/claude-accounts/claude-profile-wsl-router.ts
index e5e8fc2c6bb..7c4ec6861f8 100644
--- a/src/main/claude-accounts/claude-profile-wsl-router.ts
+++ b/src/main/claude-accounts/claude-profile-wsl-router.ts
@@ -13,6 +13,7 @@ import { getWslHomeAsync, listRunningWslDistrosAsync } from '../wsl'
 import { ensureWslPinnedRuntime } from '../wsl/wsl-pinned-runtime'
 import { relayBundleCandidates } from '../ssh/relay-bundle-paths'
 import { runWslProcess, type WslSpec } from '../wsl/wsl-runner'
+import { describeWslProcessFailure } from '../wsl/wsl-process-failure'
 import { claudeProfileMarkerPath, type ClaudeProfileDescriptor } from './claude-profile-paths'
 import type { ClaudeProfileRouterSettings } from './claude-profile-router'
 import { claudeProfileMissing, claudeProfileSetupFailed } from './claude-profile-launch-errors'
@@ -262,9 +263,7 @@ async function writePointer(distro: string, pointer: string, home: string): Prom
 async function runGuest(distro: string, spec: WslSpec, timeoutMs = 15_000): Promise<string> {
   const result = await runWslProcess({ ...spec, distro, timeoutMs, maxOutputBytes: 256 * 1024 })
   if (result.code !== 0 || result.timedOut) {
-    throw new Error(
-      `WSL ${distro}: ${result.stderr.trim() || (result.timedOut ? 'timed out' : 'command failed')}`
-    )
+    throw new Error(`WSL ${distro}: ${describeWslProcessFailure(result)}`)
   }
   return result.stdout.trim()
 }
diff --git a/src/main/cli/wsl-cli-installer.ts b/src/main/cli/wsl-cli-installer.ts
index 51a3ea8c59e..478d8d3ad01 100644
--- a/src/main/cli/wsl-cli-installer.ts
+++ b/src/main/cli/wsl-cli-installer.ts
@@ -1,6 +1,7 @@
 import type { CliInstallStatus } from '../../shared/cli-install-types'
 import { getDefaultWslDistro } from '../wsl'
 import { runWslProcess } from '../wsl/wsl-runner'
+import { describeWslProcessFailure } from '../wsl/wsl-process-failure'
 import { CliInstaller } from './cli-installer'
 import {
   buildManagedLegacyRemoveCommand,
@@ -305,7 +306,7 @@ async function runWslCommand(
     throw new WslCliLoginPathUnavailableError(distro)
   }
   if (result.code !== 0) {
-    throw new Error(result.stderr.trim() || `WSL command failed with exit code ${result.code}.`)
+    throw new Error(describeWslProcessFailure(result))
   }
   return result.stdout
 }
diff --git a/src/main/git/command-runner/wsl-host-failure.ts b/src/main/git/command-runner/wsl-host-failure.ts
index 85105e00e5d..b240069994e 100644
--- a/src/main/git/command-runner/wsl-host-failure.ts
+++ b/src/main/git/command-runner/wsl-host-failure.ts
@@ -1,8 +1,6 @@
+import { isWslHostFailureExitCode, readWslHostDiagnostic } from '../../wsl/wsl-process-failure'
 import type { ResolvedCommand } from './wsl-command-resolution'
 
-/** wsl.exe's own launch-failure exit, distinct from any status the guest process can return. */
-export const WSL_HOST_FAILURE_EXIT_CODE = 0xffffffff
-
 function outputText(value: unknown): string {
   if (typeof value === 'string') {
     return value
@@ -26,10 +24,10 @@ export function readWslHostFailureDiagnostic(
   }
   const exitCode = typeof code === 'number' ? code : typeof status === 'number' ? status : null
   // Recognize the host launch-failure shape without reclassifying guest stderr.
-  if (exitCode !== WSL_HOST_FAILURE_EXIT_CODE || outputText(stderr).trim().length > 0) {
+  if (!isWslHostFailureExitCode(exitCode) || outputText(stderr).trim().length > 0) {
     return null
   }
-  const diagnostic = outputText(stdout).replaceAll('\u0000', '').trim()
+  const diagnostic = readWslHostDiagnostic(outputText(stdout))
   return diagnostic.length > 0 ? diagnostic : 'wsl.exe reported no diagnostic.'
 }
 
diff --git a/src/main/local-worktree-filesystem.ts b/src/main/local-worktree-filesystem.ts
index 99f86ff9f91..bd7af6eb116 100644
--- a/src/main/local-worktree-filesystem.ts
+++ b/src/main/local-worktree-filesystem.ts
@@ -5,6 +5,7 @@ import { quotePosixShell } from '../shared/shell-argument-quoting'
 import { removeHostTree } from './host-tree-removal'
 import { toLinuxPath } from './wsl'
 import { resolveWslInteropSpawnCwd } from './wsl-interop-spawn-directory'
+import { describeWslProcessFailure } from './wsl/wsl-process-failure'
 import type { ReadPath, StatPath } from './worktree-orphan-gitdir-proof'
 
 export { toHostFilesystemPath, toHostRemovalPath } from './host-tree-removal'
@@ -37,7 +38,7 @@ async function runWslCommand(distro: string, command: string): Promise<string> {
     throw new Error(`WSL filesystem command timed out after ${WSL_FILE_OPERATION_TIMEOUT_MS}ms`)
   }
   if (result.code !== 0) {
-    throw Object.assign(new Error(result.stderr.trim() || `wsl.exe exited ${result.code}`), {
+    throw Object.assign(new Error(describeWslProcessFailure(result)), {
       exitCode: result.code,
       stderr: result.stderr
     })
diff --git a/src/main/wsl/wsl-process-failure.ts b/src/main/wsl/wsl-process-failure.ts
new file mode 100644
index 00000000000..017bb668eab
--- /dev/null
+++ b/src/main/wsl/wsl-process-failure.ts
@@ -0,0 +1,33 @@
+/** wsl.exe's own launch-failure exit, distinct from any status the guest process can return. */
+const WSL_HOST_FAILURE_EXIT_CODE = 0xffffffff
+
+/** Node reports the unsigned DWORD; >>> 0 also folds a signed -1. */
+export function isWslHostFailureExitCode(code: number | null | undefined): boolean {
+  return typeof code === 'number' && code >>> 0 === WSL_HOST_FAILURE_EXIT_CODE
+}
+
+/** wsl.exe writes its own errors to stdout; strip UTF-16LE NULs left when WSL_UTF8 was ignored. */
+export function readWslHostDiagnostic(stdout: string): string {
+  return stdout.replaceAll('\u0000', '').trim()
+}
+
+/** Why a guest command failed: its stderr, else wsl.exe's own error, else the exit status. */
+export function describeWslProcessFailure(result: {
+  code: number | null
+  stdout: string
+  stderr: string
+  timedOut: boolean
+}): string {
+  const stderr = result.stderr.trim()
+  if (stderr) {
+    return stderr
+  }
+  if (result.timedOut) {
+    return 'timed out'
+  }
+  if (isWslHostFailureExitCode(result.code)) {
+    const diagnostic = readWslHostDiagnostic(result.stdout)
+    return diagnostic ? `wsl.exe: ${diagnostic}` : 'wsl.exe could not start the command.'
+  }
+  return `exited with code ${result.code ?? 'unknown'}`
+}