diff --git a/src/main/external-editor-launch.test.ts b/src/main/external-editor-launch.test.ts
index 638e1ff02f7..bd7d27509e2 100644
--- a/src/main/external-editor-launch.test.ts
+++ b/src/main/external-editor-launch.test.ts
@@ -405,14 +405,44 @@ describe('resolveExternalEditorLaunchSpec', () => {
     }
   )
 
+  it.each([
+    ['C:\\Tools\\cursor.exe', '\\\\wsl.localhost\\Ubuntu\\home\\ada\\project', 'wsl+Ubuntu'],
+    [
+      'C:\\Users\\me\\AppData\\Local\\Programs\\cursor\\resources\\app\\bin\\cursor.cmd',
+      '\\\\wsl$\\Debian\\home\\ada\\project',
+      'wsl+Debian'
+    ]
+  ])('opens WSL UNC workspaces with %s in a new WSL remote window', (command, pathValue, auth) => {
+    expect(resolveExternalEditorLaunchSpec(command, pathValue, { platform: 'win32' })).toEqual({
+      kind: 'executable',
+      hideWindowsConsole: true,
+      spawnCmd: command,
+      spawnArgs: ['--new-window', '--remote', auth, '/home/ada/project']
+    })
+  })
+
+  it.each(['darwin', 'linux'] as const)(
+    'keeps WSL-looking Cursor paths local on %s',
+    (platform) => {
+      const pathValue = '\\\\wsl.localhost\\Ubuntu\\home\\ada\\project'
+      expect(resolveExternalEditorLaunchSpec('cursor', pathValue, { platform }).spawnArgs).toEqual([
+        '--new-window',
+        pathValue
+      ])
+    }
+  )
+
+  it('keeps non-WSL Windows paths local for Cursor', () => {
+    expect(
+      resolveExternalEditorLaunchSpec('C:\\Tools\\cursor.exe', '\\\\server\\share\\project', {
+        platform: 'win32'
+      }).spawnArgs
+    ).toEqual(['--new-window', '\\\\server\\share\\project'])
+  })
+
   it('does not add VS Code remote arguments to other editors', () => {
     const pathValue = '\\\\wsl.localhost\\Ubuntu\\home\\ada\\project'
 
-    expect(
-      resolveExternalEditorLaunchSpec('C:\\Tools\\cursor.exe', pathValue, {
-        platform: 'win32'
-      }).spawnArgs
-    ).toEqual(['--new-window', pathValue])
     expect(
       resolveExternalEditorLaunchSpec('C:\\Tools\\codium.exe', pathValue, {
         platform: 'win32'
diff --git a/src/main/external-editor-launch.ts b/src/main/external-editor-launch.ts
index 6fa0e867508..528256cb4ff 100644
--- a/src/main/external-editor-launch.ts
+++ b/src/main/external-editor-launch.ts
@@ -98,20 +98,25 @@ function buildExecutableArgs(
   pathValue: string,
   platform: NodeJS.Platform
 ): string[] {
-  const launcherBaseName = getLauncherBaseName(editorCommand)
-  if (launcherBaseName === 'cursor') {
-    // Why: Cursor can route bare folder launches through the last active
-    // workbench. A new window keeps "Open in Cursor" scoped to this worktree.
-    return ['--new-window', pathValue]
+  const isCursor = getLauncherBaseName(editorCommand) === 'cursor'
+  const targetArgs = buildWslRemoteTargetArgs(editorCommand, pathValue, platform, isCursor)
+  // Why: Cursor can route bare folder launches through the last active
+  // workbench. A new window keeps "Open in Cursor" scoped to this worktree.
+  return isCursor ? ['--new-window', ...targetArgs] : targetArgs
+}
+
+function buildWslRemoteTargetArgs(
+  editorCommand: string,
+  pathValue: string,
+  platform: NodeJS.Platform,
+  isCursor: boolean
+): string[] {
+  if (platform !== 'win32' || !(isCursor || isVsCodeLauncherExecutable(editorCommand))) {
+    return [pathValue]
   }
-  if (platform === 'win32' && isVsCodeLauncherExecutable(editorCommand)) {
-    const wslPath = parseWslUncPath(pathValue)
-    if (wslPath) {
-      // Why: VS Code otherwise treats a WSL UNC path as a local Windows folder.
-      return ['--remote', `wsl+${wslPath.distro}`, wslPath.linuxPath]
-    }
-  }
-  return [pathValue]
+  const wslPath = parseWslUncPath(pathValue)
+  // Why: both editors otherwise treat a WSL UNC path as a local Windows folder.
+  return wslPath ? ['--remote', `wsl+${wslPath.distro}`, wslPath.linuxPath] : [pathValue]
 }
 
 function isCompoundShellCommand(command: string): boolean {
diff --git a/src/wsl-guest/preflight-handler.test.ts b/src/wsl-guest/preflight-handler.test.ts
index 0a415f72015..8da1f6cf682 100644
--- a/src/wsl-guest/preflight-handler.test.ts
+++ b/src/wsl-guest/preflight-handler.test.ts
@@ -40,28 +40,20 @@ import {
   PreflightHandler
 } from './preflight-handler'
 
-function lookupArgs(command: string, mode: '-lc' | '-ilc' = '-lc'): string[] {
+function shLookupScript(command: string): string {
   return [
-    mode,
-    [
-      buildPosixCommandPathLookupScript({ kind: 'literal', value: command }),
-      'if [ -n "$resolved" ]; then',
-      'printf \'__ORCA_AGENT_PATH__%s\\n\' "$resolved"',
-      'fi'
-    ].join('\n')
-  ]
+    buildPosixCommandPathLookupScript(
+      { kind: 'literal', value: command },
+      { skipWindowsMountDirs: true }
+    ),
+    'if [ -n "$resolved" ]; then',
+    'printf \'__ORCA_AGENT_PATH__%s\\n\' "$resolved"',
+    'fi'
+  ].join('\n')
 }
 
-function fishLookupArgs(command: string): string[] {
-  return [
-    '-ilc',
-    [
-      `set -l resolved (command -v ${command} 2>/dev/null)`,
-      'if test -n "$resolved"',
-      'printf \'__ORCA_AGENT_PATH__%s\\n\' "$resolved"',
-      'end'
-    ].join('\n')
-  ]
+function lookupArgs(command: string, mode: '-lc' | '-ilc' = '-lc'): string[] {
+  return [mode, shLookupScript(command)]
 }
 
 beforeEach(() => {
@@ -102,10 +94,18 @@ describe('buildCommandLookupSpecs', () => {
     })
   })
 
-  it('uses fish syntax for trusted fish shells', () => {
+  it('skips Windows-mounted PATH dirs so a Windows-only shim is not a guest install', () => {
+    const [shellSpec] = buildCommandLookupSpecs('codex', 'linux', { SHELL: '/bin/bash' }, null)
+    expect(shellSpec.args[1]).toContain('/proc/mounts')
+    expect(shellSpec.args[1]).toBe(shLookupScript('codex'))
+  })
+
+  it('runs the POSIX lookup under the fish login PATH for trusted fish shells', () => {
+    const script = shLookupScript('codex')
+    const fishQuoted = `'${script.replace(/\\/g, '\\\\').replace(/'/g, "\\'")}'`
     expect(buildCommandLookupSpecs('codex', 'linux', { SHELL: '/usr/bin/fish' }, null)[0]).toEqual({
       file: '/usr/bin/fish',
-      args: fishLookupArgs("'codex'")
+      args: ['-ilc', `exec /bin/sh -c ${fishQuoted}`]
     })
   })
 
diff --git a/src/wsl-guest/preflight-handler.ts b/src/wsl-guest/preflight-handler.ts
index 28324b95a7e..77a41217f33 100644
--- a/src/wsl-guest/preflight-handler.ts
+++ b/src/wsl-guest/preflight-handler.ts
@@ -268,7 +268,12 @@ function buildPosixCommandLookupSpec(command: string, shell: string): CommandLoo
 function buildShCommandLookupScript(command: string): string {
   // Why: login shells may define aliases or functions that mask the PATH executable.
   return [
-    buildPosixCommandPathLookupScript({ kind: 'literal', value: command }),
+    // Why: WSL appends the Windows PATH, so a Windows-only npm shim would
+    // otherwise read as a guest install; same skip as host-side WSL detection.
+    buildPosixCommandPathLookupScript(
+      { kind: 'literal', value: command },
+      { skipWindowsMountDirs: true }
+    ),
     'if [ -n "$resolved" ]; then',
     `printf '${AGENT_PATH_PREFIX}%s\\n' "$resolved"`,
     'fi'
@@ -276,13 +281,8 @@ function buildShCommandLookupScript(command: string): string {
 }
 
 function buildFishCommandLookupScript(command: string): string {
-  const quotedCommand = shellQuote(command)
-  return [
-    `set -l resolved (command -v ${quotedCommand} 2>/dev/null)`,
-    'if test -n "$resolved"',
-    `printf '${AGENT_PATH_PREFIX}%s\\n' "$resolved"`,
-    'end'
-  ].join('\n')
+  // Why: fish only supplies its login PATH; the POSIX walk owns the Windows-mount skip.
+  return `exec /bin/sh -c ${fishQuote(buildShCommandLookupScript(command))}`
 }
 
 function resolveAccountLoginShell(
@@ -327,6 +327,7 @@ function getShellCommandMode(shell: string): '-lc' | '-ilc' {
   return shellName === 'sh' || shellName === 'dash' ? '-lc' : '-ilc'
 }
 
-function shellQuote(value: string): string {
-  return `'${value.replace(/'/g, "'\\''")}'`
+// Fish single quotes treat only `\\` and `\'` as escapes.
+function fishQuote(value: string): string {
+  return `'${value.replace(/\\/g, '\\\\').replace(/'/g, "\\'")}'`
 }