Fix Windows npm shim PTY launches

src/core/windows-cmd-launch.ts

@@ -1,5 +1,5 @@
-import { accessSync, constants } from "node:fs";
-import { extname, join } from "node:path";
+import { accessSync, constants, readFileSync } from "node:fs";
+import { dirname, extname, join, resolve } from "node:path";
 
 const WINDOWS_CMD_META_CHARS_REGEXP = /([()\][%!^"`<>&|;, *?])/g;
 const WINDOWS_CMD_EXTENSIONS = new Set([".cmd", ".bat"]);
@@ -55,14 +55,18 @@ function getWindowsPathExtensions(env: NodeJS.ProcessEnv): string[] {
 }
 
 function resolveWindowsBinaryExtension(binary: string, env: NodeJS.ProcessEnv): string | null {
+	return resolveWindowsBinaryPath(binary, env)?.extension ?? null;
+}
+
+function resolveWindowsBinaryPath(binary: string, env: NodeJS.ProcessEnv): { path: string; extension: string } | null {
 	const trimmed = binary.trim();
 	if (!trimmed) {
 		return null;
 	}
 
 	const extension = extname(trimmed);
 	if (extension) {
-		return extension.toLowerCase();
+		return canAccessPath(trimmed) ? { path: trimmed, extension: extension.toLowerCase() } : null;
 	}
 
 	const pathExtensions = getWindowsPathExtensions(env);
@@ -71,7 +75,7 @@ function resolveWindowsBinaryExtension(binary: string, env: NodeJS.ProcessEnv):
 		for (const pathExtension of pathExtensions) {
 			const candidate = `${trimmed}${pathExtension}`;
 			if (canAccessPath(candidate)) {
-				return pathExtension.toLowerCase();
+				return { path: candidate, extension: pathExtension.toLowerCase() };
 			}
 		}
 		return null;
@@ -89,13 +93,39 @@ function resolveWindowsBinaryExtension(binary: string, env: NodeJS.ProcessEnv):
 		for (const pathExtension of pathExtensions) {
 			const candidate = join(pathEntry, `${trimmed}${pathExtension}`);
 			if (canAccessPath(candidate)) {
-				return pathExtension.toLowerCase();
+				return { path: candidate, extension: pathExtension.toLowerCase() };
 			}
 		}
 	}
 	return null;
 }
 
+function resolveDp0Path(shimPath: string, value: string): string {
+	const shimDirectory = dirname(shimPath);
+	return resolve(value.replace(/^%dp0%([\\/])/i, `${shimDirectory}$1`));
+}
+
+function extractWindowsNpmShimTarget(shimPath: string): string | null {
+	let content: string;
+	try {
+		content = readFileSync(shimPath, "utf8");
+	} catch {
+		return null;
+	}
+
+	const directTarget = content.match(/"(%dp0%[\\/][^"]+\.(?:exe|com))"\s+%[*]/i)?.[1];
+	if (directTarget) {
+		return resolveDp0Path(shimPath, directTarget);
+	}
+
+	const nodeScriptTarget = content.match(/"%_prog%"\s+"(%dp0%[\\/][^"]+\.(?:js|mjs|cjs))"\s+%[*]/i)?.[1];
+	if (nodeScriptTarget) {
+		return resolveDp0Path(shimPath, nodeScriptTarget);
+	}
+
+	return null;
+}
+
 function normalizeWindowsCmdArgument(value: string): string {
 	return value.replaceAll("\r\n", "\n").replaceAll("\r", "\n").replaceAll("\n", "\\n");
 }
@@ -132,6 +162,37 @@ export function buildWindowsCmdArgsArray(binary: string, args: string[]): string
 	return ["/d", "/s", "/c", `"${shellCommand}"`];
 }
 
+export function resolveWindowsNpmShimLaunch(
+	binary: string,
+	args: string[],
+	platform: NodeJS.Platform = process.platform,
+	env: NodeJS.ProcessEnv = process.env,
+): { binary: string; args: string[] } | null {
+	if (platform !== "win32") {
+		return null;
+	}
+
+	const resolved = resolveWindowsBinaryPath(binary, env);
+	if (!resolved || resolved.extension !== ".cmd") {
+		return null;
+	}
+
+	const target = extractWindowsNpmShimTarget(resolved.path);
+	if (!target) {
+		return null;
+	}
+
+	const targetExtension = extname(target).toLowerCase();
+	if (targetExtension === ".exe" || targetExtension === ".com") {
+		return canAccessPath(target) ? { binary: target, args } : null;
+	}
+	if (targetExtension === ".js" || targetExtension === ".mjs" || targetExtension === ".cjs") {
+		return { binary: process.execPath, args: [target, ...args] };
+	}
+
+	return null;
+}
+
 export function shouldUseWindowsCmdLaunch(
 	binary: string,
 	platform: NodeJS.Platform = process.platform,

src/terminal/pty-session.ts

@@ -3,6 +3,7 @@ import * as pty from "node-pty";
 import {
 	buildWindowsCmdArgsCommandLine,
 	resolveWindowsComSpec,
+	resolveWindowsNpmShimLaunch,
 	shouldUseWindowsCmdLaunch,
 } from "../core/windows-cmd-launch";
 
@@ -87,9 +88,14 @@ export class PtySession {
 		const normalizedArgs = typeof args === "string" ? [args] : args;
 		const terminalName = env?.TERM?.trim() || process.env.TERM?.trim() || "xterm-256color";
 		const launchEnv: NodeJS.ProcessEnv = env ? { ...process.env, ...env } : process.env;
-		const useWindowsShellLaunch = shouldUseWindowsCmdLaunch(binary, process.platform, launchEnv);
-		const spawnBinary = useWindowsShellLaunch ? resolveWindowsComSpec(launchEnv) : binary;
-		const spawnArgs = useWindowsShellLaunch ? buildWindowsCmdArgsCommandLine(binary, normalizedArgs) : normalizedArgs;
+		const windowsShimLaunch = resolveWindowsNpmShimLaunch(binary, normalizedArgs, process.platform, launchEnv);
+		const useWindowsShellLaunch =
+			!windowsShimLaunch && shouldUseWindowsCmdLaunch(binary, process.platform, launchEnv);
+		const spawnBinary =
+			windowsShimLaunch?.binary ?? (useWindowsShellLaunch ? resolveWindowsComSpec(launchEnv) : binary);
+		const spawnArgs =
+			windowsShimLaunch?.args ??
+			(useWindowsShellLaunch ? buildWindowsCmdArgsCommandLine(binary, normalizedArgs) : normalizedArgs);
 		const ptyOptions: pty.IPtyForkOptions = {
 			name: terminalName,
 			cwd,

test/runtime/core/windows-cmd-launch.test.ts

@@ -1,9 +1,9 @@
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { afterEach, describe, expect, it } from "vitest";
 
-import { shouldUseWindowsCmdLaunch } from "../../../src/core/windows-cmd-launch";
+import { resolveWindowsNpmShimLaunch, shouldUseWindowsCmdLaunch } from "../../../src/core/windows-cmd-launch";
 
 function createWindowsBinary(directory: string, fileName: string): string {
 	const filePath = join(directory, fileName);
@@ -99,4 +99,85 @@ describe("shouldUseWindowsCmdLaunch", () => {
 			}),
 		).toBe(true);
 	});
+
+	it("resolves npm .cmd shims that forward to a native executable", () => {
+		const tempDirectory = mkdtempSync(join(tmpdir(), "kanban-win-launch-"));
+		tempDirectories.push(tempDirectory);
+		mkdirSync(join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin"), { recursive: true });
+		writeFileSync(join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin", "claude.exe"), "");
+		writeFileSync(
+			join(tempDirectory, "claude.cmd"),
+			["@ECHO off", 'CALL "%dp0%\\node_modules\\@anthropic-ai\\claude-code\\bin\\claude.exe" %*'].join("\n"),
+		);
+
+		const launch = resolveWindowsNpmShimLaunch("claude", ["--append-system-prompt", "long prompt"], "win32", {
+			PATH: tempDirectory,
+			PATHEXT: ".com;.exe;.bat;.cmd",
+		});
+
+		expect(launch).toEqual({
+			binary: join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin", "claude.exe"),
+			args: ["--append-system-prompt", "long prompt"],
+		});
+	});
+
+	it("resolves npm .cmd shim %dp0% paths case-insensitively", () => {
+		const tempDirectory = mkdtempSync(join(tmpdir(), "kanban-win-launch-"));
+		tempDirectories.push(tempDirectory);
+		mkdirSync(join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin"), { recursive: true });
+		writeFileSync(join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin", "claude.exe"), "");
+		writeFileSync(
+			join(tempDirectory, "claude.cmd"),
+			["@ECHO off", 'CALL "%DP0%\\node_modules\\@anthropic-ai\\claude-code\\bin\\claude.exe" %*'].join("\n"),
+		);
+
+		const launch = resolveWindowsNpmShimLaunch("claude", ["--foo"], "win32", {
+			PATH: tempDirectory,
+			PATHEXT: ".com;.exe;.bat;.cmd",
+		});
+
+		expect(launch).toEqual({
+			binary: join(tempDirectory, "node_modules", "@anthropic-ai", "claude-code", "bin", "claude.exe"),
+			args: ["--foo"],
+		});
+	});
+
+	it("falls back when npm .cmd shim target executable is missing", () => {
+		const tempDirectory = mkdtempSync(join(tmpdir(), "kanban-win-launch-"));
+		tempDirectories.push(tempDirectory);
+		writeFileSync(
+			join(tempDirectory, "claude.cmd"),
+			["@ECHO off", 'CALL "%dp0%\\node_modules\\@anthropic-ai\\claude-code\\bin\\claude.exe" %*'].join("\n"),
+		);
+
+		const launch = resolveWindowsNpmShimLaunch("claude", ["--foo"], "win32", {
+			PATH: tempDirectory,
+			PATHEXT: ".com;.exe;.bat;.cmd",
+		});
+
+		expect(launch).toBeNull();
+	});
+
+	it("resolves npm .cmd shims that forward to a Node script", () => {
+		const tempDirectory = mkdtempSync(join(tmpdir(), "kanban-win-launch-"));
+		tempDirectories.push(tempDirectory);
+		writeFileSync(
+			join(tempDirectory, "codex.cmd"),
+			[
+				"@ECHO off",
+				'IF EXIST "%dp0%\\node.exe" SET "_prog=%dp0%\\node.exe"',
+				'endLocal & goto #_undefined_# 2>NUL || "%_prog%" "%dp0%\\node_modules\\@openai\\codex\\bin\\codex.js" %*',
+			].join("\n"),
+		);
+
+		const launch = resolveWindowsNpmShimLaunch("codex", ["--foo"], "win32", {
+			PATH: tempDirectory,
+			PATHEXT: ".com;.exe;.bat;.cmd",
+		});
+
+		expect(launch).toEqual({
+			binary: process.execPath,
+			args: [join(tempDirectory, "node_modules", "@openai", "codex", "bin", "codex.js"), "--foo"],
+		});
+	});
 });

test/runtime/terminal/pty-session.test.ts

@@ -1,4 +1,4 @@
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
@@ -87,6 +87,7 @@ describe("PtySession", () => {
 	it("launches through cmd shell on Windows", () => {
 		setPlatform("win32");
 		process.env.ComSpec = "C:\\Windows\\System32\\cmd.exe";
+		process.env.PATH = "";
 		const ptyProcess = createMockPtyProcess();
 		ptyMocks.spawn.mockReturnValue(ptyProcess);
 
@@ -111,6 +112,7 @@ describe("PtySession", () => {
 	it("does not over-quote bare executables on Windows", () => {
 		setPlatform("win32");
 		process.env.ComSpec = "C:\\Windows\\System32\\cmd.exe";
+		process.env.PATH = "";
 		const ptyProcess = createMockPtyProcess();
 		ptyMocks.spawn.mockReturnValue(ptyProcess);
 
@@ -162,6 +164,7 @@ describe("PtySession", () => {
 	it("preserves full prompt text on Windows", () => {
 		setPlatform("win32");
 		process.env.ComSpec = "C:\\Windows\\System32\\cmd.exe";
+		process.env.PATH = "";
 		const ptyProcess = createMockPtyProcess();
 		ptyMocks.spawn.mockReturnValue(ptyProcess);
 
@@ -184,6 +187,40 @@ describe("PtySession", () => {
 		expect(cmdArgs).toContain("context");
 	});
 
+	it("launches npm .cmd shims through their target executable on Windows", () => {
+		setPlatform("win32");
+		const windowsBinDir = mkdtempSync(join(tmpdir(), "kanban-win-shim-"));
+		const target = join(windowsBinDir, "node_modules", "@anthropic-ai", "claude-code", "bin", "claude.exe");
+		mkdirSync(join(windowsBinDir, "node_modules", "@anthropic-ai", "claude-code", "bin"), { recursive: true });
+		writeFileSync(
+			join(windowsBinDir, "claude.cmd"),
+			'@ECHO off\n"%dp0%\\node_modules\\@anthropic-ai\\claude-code\\bin\\claude.exe" %*',
+		);
+		writeFileSync(target, "");
+		const ptyProcess = createMockPtyProcess();
+		ptyMocks.spawn.mockReturnValue(ptyProcess);
+
+		try {
+			PtySession.spawn({
+				binary: "claude",
+				args: ["--append-system-prompt", "x".repeat(9000)],
+				cwd: "C:/repo",
+				env: {
+					PATH: windowsBinDir,
+					PATHEXT: ".com;.exe;.bat;.cmd",
+				},
+				cols: 120,
+				rows: 40,
+			});
+		} finally {
+			rmSync(windowsBinDir, { recursive: true, force: true });
+		}
+
+		expect(ptyMocks.spawn).toHaveBeenCalledTimes(1);
+		expect(ptyMocks.spawn.mock.calls[0]?.[0]).toBe(target);
+		expect(ptyMocks.spawn.mock.calls[0]?.[1]).toEqual(["--append-system-prompt", "x".repeat(9000)]);
+	});
+
 	it("does not use cmd shell outside Windows", () => {
 		setPlatform("darwin");
 		const ptyProcess = createMockPtyProcess();