fix(server): stop detecting Windows PowerShell shims

packages/server/src/utils/executable.test.ts

@@ -138,7 +138,7 @@ describe("executableExists", () => {
     expect(executableExists("/usr/local/bin/codex", exists)).toBe("/usr/local/bin/codex");
   });
 
-  test("on Windows, falls back to .exe, .cmd, then .ps1 for extensionless paths", () => {
+  test("on Windows, falls back to .exe, then .cmd for extensionless paths", () => {
     const originalPlatform = process.platform;
     Object.defineProperty(process, "platform", { value: "win32", writable: true });
     try {
@@ -150,6 +150,18 @@ describe("executableExists", () => {
     }
   });
 
+  test("on Windows, ignores PowerShell scripts for extensionless paths", () => {
+    const originalPlatform = process.platform;
+    Object.defineProperty(process, "platform", { value: "win32", writable: true });
+    try {
+      const exists = (candidate: string) => candidate === "C:\\tools\\codex.ps1";
+
+      expect(executableExists("C:\\tools\\codex", exists)).toBeNull();
+    } finally {
+      Object.defineProperty(process, "platform", { value: originalPlatform, writable: true });
+    }
+  });
+
   test("returns null when no matching path exists", () => {
     expect(executableExists("/missing/codex", () => false)).toBeNull();
   });

packages/server/src/utils/executable.ts

@@ -40,25 +40,6 @@ export function isWindowsCommandScript(executablePath: string): boolean {
   return process.platform === "win32" && (extension === ".cmd" || extension === ".bat");
 }
 
-export function isWindowsPowerShellScript(executablePath: string): boolean {
-  return process.platform === "win32" && extname(executablePath).toLowerCase() === ".ps1";
-}
-
-export function windowsPowerShellScriptArgs(scriptPath: string, args: string[]): string[] {
-  const argvBase64 = Buffer.from(JSON.stringify(args), "utf16le").toString("base64");
-  const escapedScriptPath = scriptPath.replace(/'/g, "''");
-  const command = [
-    "$ErrorActionPreference = 'Stop'",
-    `$argvJson = [System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String('${argvBase64}'))`,
-    "$argv = @((ConvertFrom-Json -InputObject $argvJson))",
-    `& '${escapedScriptPath}' @argv`,
-    "exit $LASTEXITCODE",
-  ].join("; ");
-  const encodedCommand = Buffer.from(command, "utf16le").toString("base64");
-
-  return ["-NoProfile", "-ExecutionPolicy", "Bypass", "-EncodedCommand", encodedCommand];
-}
-
 async function probeExecutable(executablePath: string): Promise<boolean> {
   return await new Promise((resolve) => {
     let settled = false;
@@ -78,19 +59,12 @@ async function probeExecutable(executablePath: string): Promise<boolean> {
 
     let child: ChildProcess;
     try {
-      const isPowerShellScript = isWindowsPowerShellScript(executablePath);
-      child = spawn(
-        isPowerShellScript ? "powershell.exe" : executablePath,
-        isPowerShellScript
-          ? windowsPowerShellScriptArgs(executablePath, ["--version"])
-          : ["--version"],
-        {
-          stdio: "ignore",
-          windowsHide: true,
-          // Windows batch shims (.cmd/.bat) require cmd.exe; native binaries do not.
-          shell: isWindowsCommandScript(executablePath),
-        },
-      );
+      child = spawn(executablePath, ["--version"], {
+        stdio: "ignore",
+        windowsHide: true,
+        // Windows batch shims (.cmd/.bat) require cmd.exe; native binaries do not.
+        shell: isWindowsCommandScript(executablePath),
+      });
     } catch {
       settle(false);
       return;
@@ -128,7 +102,7 @@ export function executableExists(
 ): string | null {
   if (exists(executablePath)) return executablePath;
   if (process.platform === "win32" && !extname(executablePath)) {
-    for (const ext of [".exe", ".cmd", ".ps1"]) {
+    for (const ext of [".exe", ".cmd"]) {
       const candidate = executablePath + ext;
       if (exists(candidate)) return candidate;
     }

packages/server/src/utils/spawn.launch-regression.test.ts

@@ -216,24 +216,12 @@ describe.runIf(process.platform === "win32")("Windows spawn launch regression",
     expect(result.stdout.trim()).toBe("ARGV_OK");
   });
 
-  test("detects and launches a PowerShell shim from PATH without corrupting JSON args", async () => {
+  test("does not detect a PowerShell shim from PATH", async () => {
     const fixture = makeFixture({ includeCmdShim: false });
 
     await withWindowsPathEntry(fixture.root, async () => {
       const detected = await findExecutable("claude");
-      expect(detected?.toLowerCase()).toBe(fixture.powerShellShim.toLowerCase());
-
-      const result = await runFixture({
-        command: detected!,
-        args: fixture.expectedArgs,
-        shell: false,
-      });
-
-      expect(result.error).toBeNull();
-      expect(result.code).toBe(0);
-      expect(result.signal).toBeNull();
-      expect(result.stderr).toBe("");
-      expect(result.stdout.trim()).toBe("ARGV_OK");
+      expect(detected).toBeNull();
     });
   });
 });

packages/server/src/utils/spawn.ts

@@ -1,13 +1,7 @@
 import { execFile, spawn, type ChildProcess, type SpawnOptions } from "node:child_process";
 import { promisify } from "node:util";
 
-import {
-  isWindowsCommandScript,
-  isWindowsPowerShellScript,
-  quoteWindowsArgument,
-  quoteWindowsCommand,
-  windowsPowerShellScriptArgs,
-} from "./executable.js";
+import { isWindowsCommandScript, quoteWindowsArgument, quoteWindowsCommand } from "./executable.js";
 
 const execFileAsync = promisify(execFile);
 
@@ -30,14 +24,6 @@ export function spawnProcess(
   options?: SpawnOptions,
 ): ChildProcess {
   const isWindows = process.platform === "win32";
-  if (isWindowsPowerShellScript(command)) {
-    return spawn("powershell.exe", windowsPowerShellScriptArgs(command, args), {
-      ...options,
-      shell: false,
-      windowsHide: true,
-    });
-  }
-
   const shell = isWindowsCommandScript(command) ? true : (options?.shell ?? isWindows);
 
   const shouldQuoteForShell = isWindows && shell !== false;
@@ -57,18 +43,6 @@ export async function execCommand(
   options?: ExecCommandOptions,
 ): Promise<ExecCommandResult> {
   const isWindows = process.platform === "win32";
-  if (isWindowsPowerShellScript(command)) {
-    return execFileAsync("powershell.exe", windowsPowerShellScriptArgs(command, args), {
-      cwd: options?.cwd,
-      env: options?.env,
-      encoding: options?.encoding ?? "utf8",
-      timeout: options?.timeout,
-      maxBuffer: options?.maxBuffer,
-      shell: false,
-      windowsHide: true,
-    }) as Promise<ExecCommandResult>;
-  }
-
   const shell = isWindowsCommandScript(command) ? true : isWindows;
   const shouldQuoteForShell = isWindows && shell !== false;
   const resolvedCommand = shouldQuoteForShell ? quoteWindowsCommand(command) : command;