feat: add Windows Copilot CLI support with cliArgs and .bat/.cmd handling

src/services/copilot.ts

@@ -7,48 +7,95 @@ import fg from "fast-glob";
 
 const execFileAsync = promisify(execFile);
 
-let cachedCliPath: string | null = null;
-let cachedCliPathTimestamp = 0;
+export type CopilotCliConfig = {
+  cliPath: string;
+  cliArgs?: string[];
+};
+
+let cachedCliConfig: CopilotCliConfig | null = null;
+let cachedCliConfigTimestamp = 0;
 const CLI_CACHE_TTL_MS = 5 * 60 * 1000; // 5 minutes
 
-export async function assertCopilotCliReady(): Promise<string> {
-  const cliPath = await findCopilotCliPath();
+function cacheConfig(config: CopilotCliConfig): CopilotCliConfig {
+  cachedCliConfig = config;
+  cachedCliConfigTimestamp = Date.now();
+  return config;
+}
+
+export async function assertCopilotCliReady(): Promise<CopilotCliConfig> {
+  const config = await findCopilotCliConfig();
 
   try {
-    await execFileAsync(cliPath, ["--version"], { timeout: 5000 });
+    const [cmd, args] = buildExecArgs(config, ["--version"]);
+    await execFileAsync(cmd, args, { timeout: 5000 });
   } catch {
-    throw new Error(`Copilot CLI at ${cliPath} is not working.`);
+    const desc = config.cliArgs ? `${config.cliPath} ${config.cliArgs.join(" ")}` : config.cliPath;
+    throw new Error(`Copilot CLI at ${desc} is not working.`);
   }
 
-  return cliPath;
+  return config;
 }
 
 export async function listCopilotModels(): Promise<string[]> {
-  const cliPath = await assertCopilotCliReady();
-  const { stdout } = await execFileAsync(cliPath, ["--help"], { timeout: 5000 });
+  const config = await assertCopilotCliReady();
+  const [cmd, args] = buildExecArgs(config, ["--help"]);
+  const { stdout } = await execFileAsync(cmd, args, { timeout: 5000 });
   return extractModelChoices(stdout);
 }
 
-async function findCopilotCliPath(): Promise<string> {
-  if (cachedCliPath && Date.now() - cachedCliPathTimestamp < CLI_CACHE_TTL_MS) {
-    return cachedCliPath;
+function buildExecArgs(config: CopilotCliConfig, extraArgs: string[]): [string, string[]] {
+  if (config.cliArgs && config.cliArgs.length > 0) {
+    return [config.cliPath, [...config.cliArgs, ...extraArgs]];
+  }
+  if (
+    process.platform === "win32" &&
+    (config.cliPath.endsWith(".bat") || config.cliPath.endsWith(".cmd"))
+  ) {
+    return ["cmd", ["/c", config.cliPath, ...extraArgs]];
+  }
+  return [config.cliPath, extraArgs];
+}
+
+async function findCopilotCliConfig(): Promise<CopilotCliConfig> {
+  if (cachedCliConfig && Date.now() - cachedCliConfigTimestamp < CLI_CACHE_TTL_MS) {
+    return cachedCliConfig;
+  }
+
+  const isWindows = process.platform === "win32";
+  const home = process.env.HOME ?? process.env.USERPROFILE ?? "";
+  const appData = process.env.APPDATA ?? "";
+
+  // On Windows, prefer npm-installed binary and use node + cliArgs approach.
+  // This bypasses .cmd/.bat wrapper issues that prevent direct spawning.
+  // See: https://github.com/microsoft/vscode/issues/291990
+  if (isWindows && appData) {
+    const npmLoaderPath = path.join(
+      appData,
+      "npm",
+      "node_modules",
+      "@github",
+      "copilot",
+      "npm-loader.js"
+    );
+    try {
+      await fs.access(npmLoaderPath);
+      return cacheConfig({ cliPath: process.execPath, cliArgs: [npmLoaderPath] });
+    } catch {
+      // npm binary not found, will try PATH and VS Code locations
+    }
   }
 
-  // Try PATH lookup first (works on all platforms)
-  const whichCmd = process.platform === "win32" ? "where" : "which";
+  const whichCmd = isWindows ? "where" : "which";
   try {
     const { stdout } = await execFileAsync(whichCmd, ["copilot"], { timeout: 5000 });
     const found = stdout.trim().split(/\r?\n/)[0];
     if (found) {
-      cachedCliPath = found;
-      cachedCliPathTimestamp = Date.now();
-      return found;
+      return cacheConfig({ cliPath: found });
     }
   } catch {
-    // Ignore - will try VS Code locations
+    // Not on PATH, will try VS Code locations
   }
 
-  const home = process.env.HOME ?? process.env.USERPROFILE ?? "";
   const staticLocations: string[] = [];
 
   if (process.platform === "darwin") {
@@ -61,53 +108,44 @@ async function findCopilotCliPath(): Promise<string> {
       `${home}/.config/Code - Insiders/User/globalStorage/github.copilot-chat/copilotCli/copilot`,
       `${home}/.config/Code/User/globalStorage/github.copilot-chat/copilotCli/copilot`
     );
-  } else if (process.platform === "win32") {
-    const appData = process.env.APPDATA ?? "";
-    if (appData) {
-      staticLocations.push(
-        `${appData}\\Code - Insiders\\User\\globalStorage\\github.copilot-chat\\copilotCli\\copilot.exe`,
-        `${appData}\\Code\\User\\globalStorage\\github.copilot-chat\\copilotCli\\copilot.exe`
-      );
-    }
+  } else if (isWindows && appData) {
+    staticLocations.push(
+      `${appData}\\Code - Insiders\\User\\globalStorage\\github.copilot-chat\\copilotCli\\copilot.bat`,
+      `${appData}\\Code\\User\\globalStorage\\github.copilot-chat\\copilotCli\\copilot.bat`
+    );
   }
 
   for (const location of staticLocations) {
     try {
       await fs.access(location);
-      cachedCliPath = location;
-      cachedCliPathTimestamp = Date.now();
-      return location;
+      return cacheConfig({ cliPath: location });
     } catch {
-      // Try next location
+      // Try next
     }
   }
 
-  const ext = process.platform === "win32" ? ".exe" : "";
+  const exts = isWindows ? "{.exe,.bat,.cmd}" : "";
   const normalizedHome = home.replace(/\\/g, "/");
   const globPatterns = [
-    `${normalizedHome}/.vscode-insiders/extensions/github.copilot-chat-*/copilotCli/copilot${ext}`,
-    `${normalizedHome}/.vscode/extensions/github.copilot-chat-*/copilotCli/copilot${ext}`
+    `${normalizedHome}/.vscode-insiders/extensions/github.copilot-chat-*/copilotCli/copilot${exts}`,
+    `${normalizedHome}/.vscode/extensions/github.copilot-chat-*/copilotCli/copilot${exts}`
   ];
 
   for (const pattern of globPatterns) {
     const matches = await fg(pattern, { onlyFiles: true });
     if (matches.length > 0) {
-      const normalized = path.normalize(matches[0]);
-      cachedCliPath = normalized;
-      cachedCliPathTimestamp = Date.now();
-      return normalized;
+      return cacheConfig({ cliPath: path.normalize(matches[0]) });
     }
   }
 
-  const platformHint =
-    process.platform === "win32"
-      ? " Searched APPDATA and VS Code extension paths."
-      : process.platform === "linux"
-        ? " Searched ~/.config/Code and VS Code extension paths."
-        : " Searched ~/Library/Application Support/Code and VS Code extension paths.";
+  const platformHint = isWindows
+    ? " Searched APPDATA and VS Code extension paths."
+    : process.platform === "linux"
+      ? " Searched ~/.config/Code and VS Code extension paths."
+      : " Searched ~/Library/Application Support/Code and VS Code extension paths.";
 
   throw new Error(
-    `Copilot CLI not found. Install GitHub Copilot Chat extension in VS Code.${platformHint}`
+    `Copilot CLI not found. Install GitHub Copilot Chat extension in VS Code or run: npm install -g @github/copilot.${platformHint}`
   );
 }
 

src/services/evalScaffold.ts

@@ -39,11 +39,11 @@ export async function generateEvalScaffold(options: EvalScaffoldOptions): Promis
 
   return withCwd(repoPath, async () => {
     progress("Checking Copilot CLI...");
-    const cliPath = await assertCopilotCliReady();
+    const cliConfig = await assertCopilotCliReady();
 
     progress("Starting Copilot SDK...");
     const sdk = await import("@github/copilot-sdk");
-    const client = new sdk.CopilotClient({ cliPath });
+    const client = new sdk.CopilotClient(cliConfig);
 
     try {
       progress("Creating session...");

src/services/evaluator.ts

@@ -96,9 +96,9 @@ export async function runEval(
   const runStartedAt = Date.now();
 
   progress("Starting Copilot SDK...");
-  const cliPath = await assertCopilotCliReady();
+  const cliConfig = await assertCopilotCliReady();
   const sdk = await import("@github/copilot-sdk");
-  const client = new sdk.CopilotClient({ cliPath });
+  const client = new sdk.CopilotClient(cliConfig);
 
   try {
     const results: EvalResult[] = [];

src/services/instructions.ts

@@ -24,13 +24,11 @@ export async function generateCopilotInstructions(
 
   return withCwd(repoPath, async () => {
     progress("Checking Copilot CLI...");
-    const cliPath = await assertCopilotCliReady();
+    const cliConfig = await assertCopilotCliReady();
 
     progress("Starting Copilot SDK...");
     const sdk = await import("@github/copilot-sdk");
-    const client = new sdk.CopilotClient({
-      cliPath
-    });
+    const client = new sdk.CopilotClient(cliConfig);
 
     try {
       progress("Creating session...");
@@ -113,11 +111,11 @@ export async function generateAreaInstructions(
 
   return withCwd(repoPath, async () => {
     progress(`Checking Copilot CLI for area "${area.name}"...`);
-    const cliPath = await assertCopilotCliReady();
+    const cliConfig = await assertCopilotCliReady();
 
     progress(`Starting Copilot SDK for area "${area.name}"...`);
     const sdk = await import("@github/copilot-sdk");
-    const client = new sdk.CopilotClient({ cliPath });
+    const client = new sdk.CopilotClient(cliConfig);
 
     try {
       const applyToPatterns = Array.isArray(area.applyTo) ? area.applyTo : [area.applyTo];