Merge remote-tracking branch 'origin/main' into dev

# Conflicts:
#	packages/server/src/server/workspace-registry-model.test.ts
#	packages/server/src/utils/worktree.ts

.github/workflows/ci.yml

@@ -102,7 +102,20 @@ jobs:
 
       - name: Run Windows-critical server tests
         working-directory: packages/server
-        run: npx vitest run src/utils/executable.test.ts src/utils/spawn.test.ts src/utils/run-git-command.test.ts src/server/agent/provider-registry.test.ts src/server/agent/provider-launch-config.test.ts src/server/agent/provider-snapshot-manager.test.ts src/server/persisted-config.test.ts
+        run: >
+          npx vitest run
+          src/utils/executable.test.ts
+          src/utils/spawn.test.ts
+          src/utils/run-git-command.test.ts
+          src/utils/checkout-git-rev-parse.test.ts
+          src/server/agent/provider-registry.test.ts
+          src/server/agent/provider-launch-config.test.ts
+          src/server/agent/provider-snapshot-manager.test.ts
+          src/server/agent/providers/claude-agent.spawn.test.ts
+          src/server/agent/providers/provider-availability.test.ts
+          src/server/workspace-registry-model.test.ts
+          src/server/persisted-config.test.ts
+          src/server/bootstrap-provider-availability.test.ts
 
   app-tests:
     runs-on: ubuntu-latest

nix/package.nix

@@ -42,7 +42,7 @@ buildNpmPackage rec {
 
   # To update: run `nix build` with lib.fakeHash, copy the `got:` hash.
   # CI auto-updates this when package-lock.json changes (see .github/workflows/).
-  npmDepsHash = "sha256-UrTPJVju3jiSlkUMfh25rWobIo9hWNVFoVewFGxRQC0=";
+  npmDepsHash = "sha256-Wn7g+VXuUe0LI733MUj+WRX/fJQHOO/HFEkqyHrWTf0=";
 
   # Prevent onnxruntime-node's install script from running during automatic
   # npm rebuild (it tries to download from api.nuget.org, which fails in the sandbox).

package-lock.json

@@ -35365,6 +35365,7 @@
         "strip-ansi": "^7.1.2",
         "tiny-invariant": "^1.3.3",
         "uuid": "^9.0.1",
+        "which": "^5.0.0",
         "ws": "^8.14.2",
         "zod": "^3.23.8",
         "zod-to-json-schema": "^3.25.1"
@@ -35588,6 +35589,15 @@
         "node": ">= 0.8"
       }
     },
+    "packages/server/node_modules/isexe": {
+      "version": "3.1.5",
+      "resolved": "https://registry.npmjs.org/isexe/-/isexe-3.1.5.tgz",
+      "integrity": "sha512-6B3tLtFqtQS4ekarvLVMZ+X+VlvQekbe4taUkf/rhVO3d/h0M2rfARm/pXLcPEsjjMsFgrFgSrhQIxcSVrBz8w==",
+      "license": "BlueOak-1.0.0",
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "packages/server/node_modules/media-typer": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-1.1.0.tgz",
@@ -35742,6 +35752,21 @@
         "node": ">= 0.6"
       }
     },
+    "packages/server/node_modules/which": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/which/-/which-5.0.0.tgz",
+      "integrity": "sha512-JEdGzHwwkrbWoGOlIHqQ5gtprKGOenpDHpxE9zVR1bWbOtYRyPPHMe9FaP6x61CmNaTThSkb0DAJte5jD+DmzQ==",
+      "license": "ISC",
+      "dependencies": {
+        "isexe": "^3.1.1"
+      },
+      "bin": {
+        "node-which": "bin/which.js"
+      },
+      "engines": {
+        "node": "^18.17.0 || >=20.5.0"
+      }
+    },
     "packages/server/node_modules/yocto-queue": {
       "version": "1.2.2",
       "resolved": "https://registry.npmjs.org/yocto-queue/-/yocto-queue-1.2.2.tgz",

packages/server/package.json

@@ -89,6 +89,7 @@
     "strip-ansi": "^7.1.2",
     "tiny-invariant": "^1.3.3",
     "uuid": "^9.0.1",
+    "which": "^5.0.0",
     "ws": "^8.14.2",
     "zod": "^3.23.8",
     "zod-to-json-schema": "^3.25.1"

packages/server/src/server/agent/agent-manager.ts

@@ -659,6 +659,12 @@ export class AgentManager {
         : overrides;
     const launchContext = this.buildLaunchContext(resolvedAgentId);
     const client = this.requireClient(handle.provider);
+    const available = await client.isAvailable();
+    if (!available) {
+      throw new Error(
+        `Provider '${handle.provider}' is not available. Please ensure the CLI is installed.`,
+      );
+    }
     const session = await client.resumeSession(handle, resumeOverrides, launchContext);
     return this.registerSession(session, normalizedConfig, resolvedAgentId, options);
   }

packages/server/src/server/agent/providers/claude-agent.spawn.test.ts

@@ -0,0 +1,103 @@
+import { EventEmitter } from "node:events";
+import type { ChildProcess } from "node:child_process";
+import {
+  query,
+  type Options,
+  type Query,
+  type SpawnOptions as ClaudeSpawnOptions,
+} from "@anthropic-ai/claude-agent-sdk";
+import { afterEach, describe, expect, test, vi } from "vitest";
+
+import { createTestLogger } from "../../../test-utils/test-logger.js";
+import * as spawnUtils from "../../../utils/spawn.js";
+import { ClaudeAgentClient } from "./claude-agent.js";
+
+function createQueryMock(events: unknown[]): Query {
+  let index = 0;
+  return {
+    next: vi.fn(async () =>
+      index < events.length
+        ? { done: false, value: events[index++] }
+        : { done: true, value: undefined },
+    ),
+    return: vi.fn(async () => ({ done: true, value: undefined })),
+    interrupt: vi.fn(async () => undefined),
+    close: vi.fn(() => undefined),
+    setPermissionMode: vi.fn(async () => undefined),
+    setModel: vi.fn(async () => undefined),
+    supportedModels: vi.fn(async () => [{ value: "opus", displayName: "Opus" }]),
+    supportedCommands: vi.fn(async () => []),
+    rewindFiles: vi.fn(async () => ({ canRewind: true })),
+    [Symbol.asyncIterator]() {
+      return this;
+    },
+  } as Query;
+}
+
+function createChildProcessStub(): ChildProcess {
+  return {
+    stderr: new EventEmitter(),
+  } as ChildProcess;
+}
+
+describe("Claude spawn override", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  test("bypasses the shell when spawning Claude Code", async () => {
+    let capturedOptions: Options | undefined;
+    const queryFactory = vi.fn(({ options }: Parameters<typeof query>[0]) => {
+      capturedOptions = options;
+      return createQueryMock([
+        {
+          type: "system",
+          subtype: "init",
+          session_id: "claude-spawn-shell-regression-session",
+          permissionMode: "default",
+          model: "opus",
+        },
+        {
+          type: "assistant",
+          message: { content: "done" },
+        },
+        {
+          type: "result",
+          subtype: "success",
+          usage: {
+            input_tokens: 1,
+            cache_read_input_tokens: 0,
+            output_tokens: 1,
+          },
+          total_cost_usd: 0,
+        },
+      ]);
+    });
+    const spawnSpy = vi.spyOn(spawnUtils, "spawnProcess").mockReturnValue(createChildProcessStub());
+    const client = new ClaudeAgentClient({
+      logger: createTestLogger(),
+      queryFactory,
+    });
+    const session = await client.createSession({
+      provider: "claude",
+      cwd: process.cwd(),
+    });
+
+    try {
+      await session.run("spawn shell regression");
+      capturedOptions?.spawnClaudeCodeProcess?.({
+        command: "node",
+        args: ["claude.js", "--mcp-config", '{"mcpServers":{"paseo":{"type":"http"}}}'],
+        cwd: process.cwd(),
+        env: {},
+        signal: new AbortController().signal,
+      } satisfies ClaudeSpawnOptions);
+    } finally {
+      await session.close();
+    }
+
+    expect(spawnSpy).toHaveBeenCalledTimes(1);
+    const spawnOptions = spawnSpy.mock.calls[0]?.[2];
+    expect(spawnOptions?.shell).toBe(false);
+  });
+});

packages/server/src/server/agent/providers/claude-agent.ts

@@ -1135,6 +1135,8 @@ export class ClaudeAgentClient implements AgentClient {
     if (command?.mode === "replace") {
       return await isCommandAvailable(command.argv[0]);
     }
+    // Default mode uses @anthropic-ai/claude-agent-sdk's bundled cli.js run
+    // via process.execPath. No external `claude` binary is required.
     return true;
   }
 

packages/server/src/server/agent/providers/codex-app-server-agent.ts

@@ -4215,7 +4215,7 @@ export class CodexAppServerAgentClient implements AgentClient {
     if (command?.mode === "replace") {
       return await isCommandAvailable(command.argv[0]);
     }
-    return true;
+    return await isCommandAvailable("codex");
   }
 
   async getDiagnostic(): Promise<{ diagnostic: string }> {

packages/server/src/server/agent/providers/opencode-agent.ts

@@ -1041,7 +1041,7 @@ export class OpenCodeAgentClient implements AgentClient {
     if (command?.mode === "replace") {
       return await isCommandAvailable(command.argv[0]);
     }
-    return true;
+    return await isCommandAvailable("opencode");
   }
 
   async getDiagnostic(): Promise<{ diagnostic: string }> {

packages/server/src/server/agent/providers/provider-availability.test.ts

@@ -0,0 +1,147 @@
+import { chmodSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, describe, expect, test } from "vitest";
+
+import { createTestLogger } from "../../../test-utils/test-logger.js";
+import type { AgentProvider } from "../agent-sdk-types.js";
+import { AgentManager } from "../agent-manager.js";
+import { AgentStorage } from "../agent-storage.js";
+
+import { ClaudeAgentClient } from "./claude-agent.js";
+import { CodexAppServerAgentClient } from "./codex-app-server-agent.js";
+import { OpenCodeAgentClient } from "./opencode-agent.js";
+
+const originalEnv = {
+  PATH: process.env.PATH,
+  PATHEXT: process.env.PATHEXT,
+};
+const tempDirs: string[] = [];
+
+function makeTempDir(prefix: string): string {
+  const dir = mkdtempSync(join(tmpdir(), prefix));
+  tempDirs.push(dir);
+  return dir;
+}
+
+function isolatePathTo(dir: string): void {
+  process.env.PATH = dir;
+  if (process.platform === "win32") {
+    process.env.PATHEXT = ".CMD";
+  }
+}
+
+function writeProviderShim(dir: string, command: string): string {
+  const filePath = process.platform === "win32" ? join(dir, `${command}.cmd`) : join(dir, command);
+  const content =
+    process.platform === "win32"
+      ? `@echo off\r\necho ${command} 1.0\r\n`
+      : `#!/bin/sh\necho ${command} 1.0\n`;
+  writeFileSync(filePath, content);
+  if (process.platform !== "win32") {
+    chmodSync(filePath, 0o755);
+  }
+  return filePath;
+}
+
+afterEach(() => {
+  process.env.PATH = originalEnv.PATH;
+  process.env.PATHEXT = originalEnv.PATHEXT;
+  for (const dir of tempDirs.splice(0)) {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+describe("default provider availability", () => {
+  test("Codex reports unavailable when the default command cannot be resolved", async () => {
+    const binDir = makeTempDir("provider-availability-codex-");
+    isolatePathTo(binDir);
+    const client = new CodexAppServerAgentClient(createTestLogger());
+
+    await expect(client.isAvailable()).resolves.toBe(false);
+  });
+
+  test("Claude reports available without a PATH binary because the SDK bundles its own cli.js", async () => {
+    const binDir = makeTempDir("provider-availability-claude-");
+    isolatePathTo(binDir);
+    const client = new ClaudeAgentClient({ logger: createTestLogger() });
+
+    await expect(client.isAvailable()).resolves.toBe(true);
+  });
+
+  test("OpenCode reports unavailable when the default command cannot be resolved", async () => {
+    const binDir = makeTempDir("provider-availability-opencode-");
+    isolatePathTo(binDir);
+    const client = new OpenCodeAgentClient(createTestLogger());
+
+    await expect(client.isAvailable()).resolves.toBe(false);
+  });
+
+  test("Codex reports available when the default command resolves from PATH", async () => {
+    const binDir = makeTempDir("provider-availability-codex-");
+    isolatePathTo(binDir);
+    writeProviderShim(binDir, "codex");
+    const client = new CodexAppServerAgentClient(createTestLogger());
+
+    await expect(client.isAvailable()).resolves.toBe(true);
+  });
+
+  test("OpenCode reports available when the default command resolves from PATH", async () => {
+    const binDir = makeTempDir("provider-availability-opencode-");
+    isolatePathTo(binDir);
+    writeProviderShim(binDir, "opencode");
+    const client = new OpenCodeAgentClient(createTestLogger());
+
+    await expect(client.isAvailable()).resolves.toBe(true);
+  });
+
+  test("AgentManager reports Codex unavailable without throwing", async () => {
+    const binDir = makeTempDir("provider-availability-manager-bin-");
+    isolatePathTo(binDir);
+    const workdir = makeTempDir("provider-availability-manager-work-");
+    const storage = new AgentStorage(join(workdir, "agents"), createTestLogger());
+    const manager = new AgentManager({
+      clients: {
+        codex: new CodexAppServerAgentClient(createTestLogger()),
+      },
+      registry: storage,
+      logger: createTestLogger(),
+    });
+
+    await expect(manager.listProviderAvailability()).resolves.toEqual([
+      {
+        provider: "codex",
+        available: false,
+        error: null,
+      },
+    ]);
+  });
+
+  test("resumeAgentFromPersistence stops before provider spawn when Codex is unavailable", async () => {
+    const binDir = makeTempDir("provider-availability-resume-bin-");
+    isolatePathTo(binDir);
+    const workdir = makeTempDir("provider-availability-resume-work-");
+    const storage = new AgentStorage(join(workdir, "agents"), createTestLogger());
+    const manager = new AgentManager({
+      clients: {
+        codex: new CodexAppServerAgentClient(createTestLogger()),
+      },
+      registry: storage,
+      logger: createTestLogger(),
+    });
+
+    await expect(
+      manager.resumeAgentFromPersistence(
+        {
+          provider: "codex" as AgentProvider,
+          sessionId: "missing-codex-session",
+          metadata: {
+            provider: "codex",
+            cwd: workdir,
+          },
+        },
+        { cwd: workdir },
+      ),
+    ).rejects.toThrow("Provider 'codex' is not available");
+  });
+});

packages/server/src/server/bootstrap-provider-availability.test.ts

@@ -0,0 +1,116 @@
+import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import pino from "pino";
+import { afterEach, describe, expect, test } from "vitest";
+import { ensureAgentLoaded } from "./agent/agent-loading.js";
+import type { PaseoDaemonConfig } from "./bootstrap.js";
+
+const originalEnv = {
+  PATH: process.env.PATH,
+  PATHEXT: process.env.PATHEXT,
+};
+
+describe("bootstrap provider availability", () => {
+  const tempRoots: string[] = [];
+
+  afterEach(async () => {
+    process.env.PATH = originalEnv.PATH;
+    process.env.PATHEXT = originalEnv.PATHEXT;
+    for (const root of tempRoots.splice(0)) {
+      await rm(root, { recursive: true, force: true });
+    }
+  });
+
+  test("loads a persisted Codex record without spawning a missing Codex binary", async () => {
+    const { createPaseoDaemon } = await import("./bootstrap.js");
+    const root = await mkdtemp(path.join(os.tmpdir(), "paseo-bootstrap-provider-"));
+    tempRoots.push(root);
+    const binDir = await mkdtemp(path.join(os.tmpdir(), "paseo-bootstrap-provider-bin-"));
+    tempRoots.push(binDir);
+    process.env.PATH = binDir;
+    if (process.platform === "win32") {
+      process.env.PATHEXT = ".CMD";
+    }
+    const paseoHome = path.join(root, ".paseo");
+    const staticDir = path.join(root, "static");
+    const agentStoragePath = path.join(paseoHome, "agents");
+    const now = new Date("2026-04-16T00:00:00.000Z").toISOString();
+    const agentId = "11111111-1111-4111-8111-111111111111";
+    await mkdir(agentStoragePath, { recursive: true });
+    await mkdir(staticDir, { recursive: true });
+    await writeFile(
+      path.join(agentStoragePath, `${agentId}.json`),
+      JSON.stringify({
+        id: agentId,
+        provider: "codex",
+        cwd: root,
+        createdAt: now,
+        updatedAt: now,
+        lastStatus: "idle",
+        lastModeId: "auto",
+        config: {
+          modeId: "auto",
+          model: "gpt-5.4",
+        },
+        persistence: {
+          provider: "codex",
+          sessionId: "codex-session-1",
+          metadata: {
+            provider: "codex",
+            cwd: root,
+          },
+        },
+      }),
+    );
+
+    const config: PaseoDaemonConfig = {
+      listen: "127.0.0.1:0",
+      paseoHome,
+      corsAllowedOrigins: [],
+      hostnames: true,
+      mcpEnabled: false,
+      staticDir,
+      mcpDebug: false,
+      agentClients: {},
+      agentStoragePath,
+      relayEnabled: false,
+      appBaseUrl: "https://app.paseo.sh",
+      openai: undefined,
+      speech: undefined,
+    };
+    const processFailures: Error[] = [];
+    const onUnhandledRejection = (reason: unknown) => {
+      processFailures.push(reason instanceof Error ? reason : new Error(String(reason)));
+    };
+    const onUncaughtException = (error: Error) => {
+      processFailures.push(error);
+    };
+    process.on("unhandledRejection", onUnhandledRejection);
+    process.on("uncaughtException", onUncaughtException);
+
+    const daemon = await createPaseoDaemon(config, pino({ level: "silent" }));
+    try {
+      await expect(daemon.agentStorage.list()).resolves.toHaveLength(1);
+      await expect(daemon.agentManager.listProviderAvailability()).resolves.toContainEqual({
+        provider: "codex",
+        available: false,
+        error: null,
+      });
+      await expect(
+        ensureAgentLoaded(agentId, {
+          agentManager: daemon.agentManager,
+          agentStorage: daemon.agentStorage,
+          logger: pino({ level: "silent" }),
+        }),
+      ).rejects.toThrow("Provider 'codex' is not available");
+      await new Promise((resolve) => setImmediate(resolve));
+      expect(processFailures).toEqual([]);
+    } finally {
+      process.off("unhandledRejection", onUnhandledRejection);
+      process.off("uncaughtException", onUncaughtException);
+      await daemon.stop().catch(() => undefined);
+      await daemon.agentManager.flush().catch(() => undefined);
+    }
+  });
+});

packages/server/src/server/workspace-git-service.ts

@@ -11,6 +11,7 @@ import {
   resolveGhPath,
   resolveAbsoluteGitDir,
 } from "../utils/checkout-git.js";
+import { parseGitRevParsePath } from "../utils/git-rev-parse-path.js";
 import { runGitCommand } from "../utils/run-git-command.js";
 import { READ_ONLY_GIT_ENV } from "./checkout-git-utils.js";
 import { normalizeWorkspaceId } from "./workspace-registry-model.js";
@@ -368,15 +369,11 @@ export class WorkspaceGitServiceImpl implements WorkspaceGitService {
 
   private async resolveCheckoutWatchRoot(cwd: string): Promise<string | null> {
     try {
-      const { stdout } = await this.deps.runGitCommand(
-        ["rev-parse", "--path-format=absolute", "--show-toplevel"],
-        {
-          cwd,
-          env: READ_ONLY_GIT_ENV,
-        },
-      );
-      const root = stdout.trim();
-      return root.length > 0 ? root : null;
+      const { stdout } = await this.deps.runGitCommand(["rev-parse", "--show-toplevel"], {
+        cwd,
+        env: READ_ONLY_GIT_ENV,
+      });
+      return parseGitRevParsePath(stdout);
     } catch {
       return null;
     }

packages/server/src/server/workspace-registry-model.test.ts

@@ -0,0 +1,106 @@
+import { describe, expect, test, vi } from "vitest";
+
+import {
+  deriveWorkspaceId,
+  detectStaleWorkspaces,
+  normalizeWorkspaceId,
+} from "./workspace-registry-model.js";
+import { createPersistedWorkspaceRecord } from "./workspace-registry.js";
+
+function createWorkspaceRecord(workspaceId: string) {
+  return createPersistedWorkspaceRecord({
+    workspaceId,
+    projectId: workspaceId,
+    cwd: workspaceId,
+    kind: "directory",
+    displayName: workspaceId.split("/").at(-1) ?? workspaceId,
+    createdAt: "2026-03-01T00:00:00.000Z",
+    updatedAt: "2026-03-01T00:00:00.000Z",
+  });
+}
+
+describe("detectStaleWorkspaces", () => {
+  test("returns workspace ids whose directories no longer exist", async () => {
+    const checkDirectoryExists = vi.fn(async (cwd: string) => cwd !== "/tmp/missing");
+
+    const staleWorkspaceIds = await detectStaleWorkspaces({
+      activeWorkspaces: [
+        createWorkspaceRecord("/tmp/existing"),
+        createWorkspaceRecord("/tmp/missing"),
+      ],
+      checkDirectoryExists,
+    });
+
+    expect(Array.from(staleWorkspaceIds)).toEqual(["/tmp/missing"]);
+    expect(checkDirectoryExists.mock.calls).toEqual([["/tmp/existing"], ["/tmp/missing"]]);
+  });
+
+  test("keeps workspaces whose directories exist even when all agents are archived", async () => {
+    const staleWorkspaceIds = await detectStaleWorkspaces({
+      activeWorkspaces: [createWorkspaceRecord("/tmp/repo"), createWorkspaceRecord("/tmp/other")],
+      checkDirectoryExists: async () => true,
+    });
+
+    expect(Array.from(staleWorkspaceIds)).toEqual([]);
+  });
+
+  test("keeps workspaces with no agents when directory exists", async () => {
+    const staleWorkspaceIds = await detectStaleWorkspaces({
+      activeWorkspaces: [
+        createWorkspaceRecord("/tmp/active"),
+        createWorkspaceRecord("/tmp/no-agents"),
+      ],
+      checkDirectoryExists: async () => true,
+    });
+
+    expect(Array.from(staleWorkspaceIds)).toEqual([]);
+  });
+});
+
+describe("deriveWorkspaceId", () => {
+  test("uses git worktree root when available", () => {
+    expect(
+      deriveWorkspaceId("/tmp/repo/packages/app", {
+        cwd: "/tmp/repo/packages/app",
+        isGit: true,
+        currentBranch: "main",
+        remoteUrl: "https://github.com/acme/repo.git",
+        worktreeRoot: "/tmp/repo",
+        isPaseoOwnedWorktree: false,
+        mainRepoRoot: null,
+      }),
+    ).toBe("/tmp/repo");
+  });
+
+  test("falls back to normalized cwd when git worktree root contains multiple lines", () => {
+    const cwd = String.raw`E:\project\node-ai`;
+
+    expect(
+      deriveWorkspaceId(cwd, {
+        cwd,
+        isGit: true,
+        currentBranch: "main",
+        remoteUrl: null,
+        worktreeRoot: `--path-format=absolute\n${cwd}`,
+        isPaseoOwnedWorktree: false,
+        mainRepoRoot: null,
+      }),
+    ).toBe(normalizeWorkspaceId(cwd));
+  });
+
+  test("falls back to normalized cwd for non-git directories", () => {
+    const cwd = "/tmp/repo/../repo/scratch";
+
+    expect(
+      deriveWorkspaceId(cwd, {
+        cwd,
+        isGit: false,
+        currentBranch: null,
+        remoteUrl: null,
+        worktreeRoot: null,
+        isPaseoOwnedWorktree: false,
+        mainRepoRoot: null,
+      }),
+    ).toBe(normalizeWorkspaceId("/tmp/repo/scratch"));
+  });
+});

packages/server/src/server/workspace-registry-model.ts

@@ -1,6 +1,7 @@
 import { resolve } from "node:path";
 
 import type { ProjectCheckoutLitePayload, ProjectPlacementPayload } from "../shared/messages.js";
+import { parseGitRevParsePath } from "../utils/git-rev-parse-path.js";
 import type { WorkspaceGitService } from "./workspace-git-service.js";
 import type { PersistedWorkspaceRecord } from "./workspace-registry.js";
 
@@ -20,7 +21,8 @@ export function normalizeWorkspaceId(cwd: string): string {
 }
 
 export function deriveWorkspaceId(cwd: string, checkout: ProjectCheckoutLitePayload): string {
-  return checkout.worktreeRoot ?? normalizeWorkspaceId(cwd);
+  const worktreeRoot = checkout.worktreeRoot ? parseGitRevParsePath(checkout.worktreeRoot) : null;
+  return worktreeRoot ?? normalizeWorkspaceId(cwd);
 }
 
 function deriveRemoteProjectKey(remoteUrl: string | null): string | null {

packages/server/src/utils/checkout-git-rev-parse.test.ts

@@ -0,0 +1,109 @@
+import { execFileSync } from "node:child_process";
+import { mkdtempSync, mkdirSync, rmSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+const VALID_WINDOWS_ROOT = String.raw`E:\project\node-ai`;
+const OLD_GIT_PATH_FORMAT_ECHO = `--path-format=absolute\n${VALID_WINDOWS_ROOT}\n`;
+const tempDirs: string[] = [];
+
+function makeTempDir(): string {
+  const dir = mkdtempSync(join(tmpdir(), "paseo-checkout-git-"));
+  tempDirs.push(dir);
+  return dir;
+}
+
+function gitResult(stdout: string) {
+  return { stdout, stderr: "", exitCode: 0 };
+}
+
+function normalizePathForPlatform(value: string): string {
+  if (process.platform !== "win32") {
+    return value;
+  }
+  return value.replace(/\\/g, "/").toLowerCase();
+}
+
+function gitCanonicalize(dir: string): string {
+  return execFileSync("git", ["-C", dir, "rev-parse", "--show-toplevel"], {
+    encoding: "utf8",
+  }).trim();
+}
+
+async function loadCheckoutGitWithRevParseTopLevelOutput(stdout: string) {
+  vi.resetModules();
+
+  const runGitCommand = vi.fn(async (args: string[]) => {
+    if (args.join(" ") === "rev-parse --show-toplevel") {
+      return gitResult(stdout);
+    }
+
+    if (args.join(" ") === "rev-parse --abbrev-ref HEAD") {
+      return gitResult("main\n");
+    }
+
+    if (args.join(" ") === "status --porcelain") {
+      return gitResult("");
+    }
+
+    if (args.join(" ") === "branch --format=%(refname:short)") {
+      return gitResult("main\n");
+    }
+
+    throw new Error(`Unexpected git command: git ${args.join(" ")}`);
+  });
+
+  vi.doMock("./run-git-command.js", () => ({ runGitCommand }));
+
+  const checkoutGit = await import("./checkout-git.js");
+  return { getCheckoutStatus: checkoutGit.getCheckoutStatus, runGitCommand };
+}
+
+describe("checkout git rev-parse path handling", () => {
+  afterEach(() => {
+    vi.doUnmock("./run-git-command.js");
+    vi.resetModules();
+    for (const dir of tempDirs.splice(0)) {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
+  it("resolves the worktree root from a nested real git checkout", async () => {
+    const repoRoot = makeTempDir();
+    const nested = join(repoRoot, "packages", "server", "src");
+    mkdirSync(nested, { recursive: true });
+    execFileSync("git", ["init"], { cwd: repoRoot, stdio: "ignore" });
+
+    const { getCheckoutStatus } = await import("./checkout-git.js");
+    const status = await getCheckoutStatus(nested);
+
+    expect(status.isGit).toBe(true);
+    if (!status.isGit) {
+      throw new Error("Expected nested checkout to be detected as a git repository");
+    }
+    expect(normalizePathForPlatform(status.repoRoot)).toBe(
+      normalizePathForPlatform(gitCanonicalize(repoRoot)),
+    );
+  });
+
+  it("rejects multi-line rev-parse stdout and never calls the removed path-format command", async () => {
+    // Pre-2.31 Git is difficult to install in CI; inject its multi-line stdout
+    // shape at the exact production command boundary that consumes rev-parse.
+    const { getCheckoutStatus, runGitCommand } =
+      await loadCheckoutGitWithRevParseTopLevelOutput(OLD_GIT_PATH_FORMAT_ECHO);
+
+    const status = await getCheckoutStatus(VALID_WINDOWS_ROOT);
+
+    expect(status).toEqual({ isGit: false });
+    expect(runGitCommand).toHaveBeenCalledWith(["rev-parse", "--show-toplevel"], expect.anything());
+    expect(runGitCommand).not.toHaveBeenCalledWith(
+      ["rev-parse", "--path-format=absolute", "--show-toplevel"],
+      expect.anything(),
+    );
+    expect(runGitCommand).not.toHaveBeenCalledWith(
+      ["rev-parse", "--git-common-dir"],
+      expect.anything(),
+    );
+  });
+});

packages/server/src/utils/checkout-git.ts

@@ -6,6 +6,7 @@ import { z } from "zod";
 import type { ParsedDiffFile } from "../server/utils/diff-highlighter.js";
 import { parseAndHighlightDiff } from "../server/utils/diff-highlighter.js";
 import { findExecutable } from "./executable.js";
+import { parseGitRevParsePath, resolveGitRevParsePath } from "./git-rev-parse-path.js";
 import { runGitCommand } from "./run-git-command.js";
 import { execCommand } from "./spawn.js";
 import { isPaseoOwnedWorktreeCwd } from "./worktree.js";
@@ -573,26 +574,25 @@ export async function getCurrentBranch(cwd: string): Promise<string | null> {
 
 async function getWorktreeRoot(cwd: string): Promise<string | null> {
   try {
-    const { stdout } = await runGitCommand(
-      ["rev-parse", "--path-format=absolute", "--show-toplevel"],
-      {
-        cwd,
-        env: READ_ONLY_GIT_ENV,
-      },
-    );
-    const root = stdout.trim();
-    return root.length > 0 ? root : null;
+    const { stdout } = await runGitCommand(["rev-parse", "--show-toplevel"], {
+      cwd,
+      env: READ_ONLY_GIT_ENV,
+    });
+    return parseGitRevParsePath(stdout);
   } catch {
     return null;
   }
 }
 
 export async function getMainRepoRoot(cwd: string): Promise<string> {
-  const { stdout: commonDirOut } = await runGitCommand(
-    ["rev-parse", "--path-format=absolute", "--git-common-dir"],
-    { cwd, env: READ_ONLY_GIT_ENV },
-  );
-  const commonDir = commonDirOut.trim();
+  const { stdout: commonDirOut } = await runGitCommand(["rev-parse", "--git-common-dir"], {
+    cwd,
+    env: READ_ONLY_GIT_ENV,
+  });
+  const commonDir = resolveGitRevParsePath(cwd, commonDirOut);
+  if (!commonDir) {
+    throw new Error("Not in a git repository");
+  }
   const normalized = realpathSync(commonDir);
 
   if (basename(normalized) === ".git") {

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

@@ -1,213 +1,157 @@
-import { promisify } from "node:util";
-import { afterEach, describe, expect, test, vi } from "vitest";
+import { chmodSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { afterEach, describe, expect, test } from "vitest";
 
-type ExecFileCallback = (error: Error | null, stdout: string, stderr: string) => void;
+import {
+  executableExists,
+  findExecutable,
+  quoteWindowsArgument,
+  quoteWindowsCommand,
+} from "./executable.js";
 
-async function loadExecutableModule(params?: {
-  execFileImpl?: (
-    command: string,
-    args: string[],
-    options: unknown,
-    callback: ExecFileCallback,
-  ) => void;
-}) {
-  vi.resetModules();
+const originalEnv = {
+  PATH: process.env.PATH,
+  PATHEXT: process.env.PATHEXT,
+};
+const tempDirs: string[] = [];
 
-  const execFileMock = vi.fn(
-    params?.execFileImpl ??
-      ((_command: string, _args: string[], _options: unknown, callback: ExecFileCallback) => {
-        callback(new Error("execFile not mocked"), "", "");
-      }),
-  );
-  Object.assign(execFileMock, {
-    [promisify.custom]: (command: string, args: string[], options: unknown) =>
-      new Promise<{ stdout: string; stderr: string }>((resolve, reject) => {
-        execFileMock(
-          command,
-          args,
-          options,
-          (error: Error | null, stdout: string, stderr: string) => {
-            if (error) {
-              reject(error);
-              return;
-            }
-            resolve({ stdout, stderr });
-          },
-        );
-      }),
-  });
-
-  vi.doMock("node:child_process", () => ({
-    execFile: execFileMock,
-  }));
-  const module = await import("./executable.js");
-  return {
-    ...module,
-    execFileMock,
-  };
+function makeTempDir(): string {
+  const dir = mkdtempSync(path.join(os.tmpdir(), "paseo-executable-test-"));
+  tempDirs.push(dir);
+  return dir;
 }
 
-describe("findExecutable", () => {
-  const originalPlatform = process.platform;
-  const missingBinaryName = "nonexistent-binary-xyz-12345";
+function prependPath(...dirs: string[]): void {
+  process.env.PATH = [...dirs, originalEnv.PATH].filter(Boolean).join(path.delimiter);
+}
 
-  function setPlatform(value: string) {
-    Object.defineProperty(process, "platform", { value, writable: true });
+function writeExecutable(filePath: string, content: string): string {
+  writeFileSync(filePath, content);
+  if (process.platform !== "win32") {
+    chmodSync(filePath, 0o755);
   }
+  return filePath;
+}
 
-  afterEach(() => {
-    setPlatform(originalPlatform);
-  });
+function writeInvokableFixture(dir: string, name: string): string {
+  if (process.platform === "win32") {
+    return writeExecutable(path.join(dir, `${name}.cmd`), "@echo off\r\necho 0.1\r\n");
+  }
+  return writeExecutable(path.join(dir, name), "#!/bin/sh\necho 0.1\n");
+}
 
-  test("on Windows, resolves executables using where.exe with inherited PATH", async () => {
-    setPlatform("win32");
-    const { execFileMock, findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(null, "C:\\Users\\boudr\\.local\\bin\\claude.exe\r\n", "");
-      },
-    });
+function writeBrokenAbsoluteFixture(dir: string): string {
+  const filePath =
+    process.platform === "win32" ? path.join(dir, "broken.exe") : path.join(dir, "broken");
+  writeFileSync(filePath, "not executable");
+  if (process.platform !== "win32") {
+    chmodSync(filePath, 0o644);
+  }
+  return filePath;
+}
 
-    await expect(findExecutable("claude")).resolves.toBe(
-      "C:\\Users\\boudr\\.local\\bin\\claude.exe",
-    );
-    expect(execFileMock).toHaveBeenCalledOnce();
-    const call = execFileMock.mock.calls[0];
-    expect(call?.[0]).toBe("where.exe");
-    expect(call?.[1]).toEqual(["claude"]);
-    expect(call?.[2]).toMatchObject({
-      encoding: "utf8",
-      windowsHide: true,
+function expectWindowsPathsEqual(actual: string | null, expected: string): void {
+  expect(actual?.toLowerCase()).toBe(expected.toLowerCase());
+}
+
+afterEach(() => {
+  process.env.PATH = originalEnv.PATH;
+  process.env.PATHEXT = originalEnv.PATHEXT;
+  for (const dir of tempDirs.splice(0)) {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+describe("findExecutable", () => {
+  describe.skipIf(process.platform === "win32")("POSIX", () => {
+    test("finds an extensionless executable and skips an earlier non-executable candidate", async () => {
+      const executableDir = makeTempDir();
+      const nonExecutableDir = makeTempDir();
+      const executable = writeExecutable(path.join(executableDir, "foo"), "#!/bin/sh\necho 0.1\n");
+      const nonExecutable = path.join(nonExecutableDir, "foo");
+      writeFileSync(nonExecutable, "#!/bin/sh\necho broken\n");
+      chmodSync(nonExecutable, 0o644);
+      prependPath(nonExecutableDir, executableDir);
+
+      await expect(findExecutable("foo")).resolves.toBe(executable);
     });
   });
 
-  test("on Windows, prefers an executable match from where.exe output", async () => {
-    setPlatform("win32");
-    const { findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(null, "C:\\nvm4w\\nodejs\\codex\r\nC:\\nvm4w\\nodejs\\codex.cmd\r\n", "");
-      },
+  describe.runIf(process.platform === "win32")("Windows", () => {
+    test("returns a working .cmd when an invalid .exe candidate appears first", async () => {
+      const dir = makeTempDir();
+      process.env.PATHEXT = [".EXE", ".CMD"].join(path.delimiter);
+      const brokenExe = path.join(dir, "foo.exe");
+      const cmd = writeExecutable(path.join(dir, "foo.cmd"), "@echo off\r\necho 0.1\r\n");
+      writeFileSync(brokenExe, "");
+      prependPath(dir);
+
+      expectWindowsPathsEqual(await findExecutable("foo"), cmd);
     });
 
-    await expect(findExecutable("codex")).resolves.toBe("C:\\nvm4w\\nodejs\\codex.cmd");
+    test("returns null when the only candidate is a broken .exe", async () => {
+      const dir = makeTempDir();
+      process.env.PATHEXT = ".EXE";
+      writeFileSync(path.join(dir, "foo.exe"), "");
+      prependPath(dir);
+
+      await expect(findExecutable("foo")).resolves.toBeNull();
+    });
+
+    test("returns a .cmd when it is the only candidate", async () => {
+      const dir = makeTempDir();
+      process.env.PATHEXT = ".CMD";
+      const cmd = writeExecutable(path.join(dir, "foo.cmd"), "@echo off\r\necho 0.1\r\n");
+      prependPath(dir);
+
+      expectWindowsPathsEqual(await findExecutable("foo"), cmd);
+    });
   });
 
-  test("on Windows, prefers .exe over .cmd, .ps1, and extensionless candidates", async () => {
-    setPlatform("win32");
-    const { findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(
-          null,
-          [
-            "C:\\nvm4w\\nodejs\\codex",
-            "C:\\nvm4w\\nodejs\\codex.ps1",
-            "C:\\nvm4w\\nodejs\\codex.cmd",
-            "C:\\nvm4w\\nodejs\\codex.exe",
-          ].join("\r\n"),
-          "",
-        );
-      },
-    });
+  test("returns an invokable absolute path", async () => {
+    const dir = makeTempDir();
+    const fixture = writeInvokableFixture(dir, "absolute-ok");
 
-    await expect(findExecutable("codex")).resolves.toBe("C:\\nvm4w\\nodejs\\codex.exe");
+    await expect(findExecutable(fixture)).resolves.toBe(fixture);
   });
 
-  test("on Windows, returns null when where.exe output is empty", async () => {
-    setPlatform("win32");
-    const { findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(null, "\r\n", "");
-      },
-    });
+  test("returns null for an absolute path that cannot spawn", async () => {
+    const dir = makeTempDir();
+    const fixture = writeBrokenAbsoluteFixture(dir);
 
-    await expect(findExecutable(missingBinaryName)).resolves.toBeNull();
+    await expect(findExecutable(fixture)).resolves.toBeNull();
   });
 
-  test("on Windows, falls back to the first extensionless candidate when needed", async () => {
-    setPlatform("win32");
-    const { findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(null, "C:\\nvm4w\\nodejs\\codex\r\n", "");
-      },
-    });
+  test("returns null when the command is not on PATH", async () => {
+    const dir = makeTempDir();
+    prependPath(dir);
 
-    await expect(findExecutable("codex")).resolves.toBe("C:\\nvm4w\\nodejs\\codex");
-  });
-
-  test("on Unix, uses the last line from which output", async () => {
-    const { execFileMock, findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(null, "/usr/local/bin/codex\n", "");
-      },
-    });
-
-    await expect(findExecutable("codex")).resolves.toBe("/usr/local/bin/codex");
-    expect(execFileMock).toHaveBeenCalledWith(
-      process.platform === "win32" ? "where.exe" : "which",
-      ["codex"],
-      process.platform === "win32" ? { encoding: "utf8", windowsHide: true } : { encoding: "utf8" },
-      expect.any(Function),
-    );
-  });
-
-  test.skipIf(process.platform === "win32")(
-    "warns and returns null when the final which line is not an absolute path",
-    async () => {
-      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
-      const { findExecutable } = await loadExecutableModule({
-        execFileImpl: (_command, _args, _options, callback) => {
-          callback(null, "codex\n", "");
-        },
-      });
-
-      await expect(findExecutable("codex")).resolves.toBeNull();
-      expect(warnSpy).toHaveBeenCalledOnce();
-
-      warnSpy.mockRestore();
-    },
-  );
-
-  test("returns null when which lookup fails", async () => {
-    const { findExecutable } = await loadExecutableModule({
-      execFileImpl: (_command, _args, _options, callback) => {
-        callback(new Error("which failed"), "", "");
-      },
-    });
-
-    await expect(findExecutable(missingBinaryName)).resolves.toBeNull();
+    await expect(findExecutable("paseo-definitely-missing-command")).resolves.toBeNull();
   });
 });
 
 describe("executableExists", () => {
-  const originalPlatform = process.platform;
-
-  function setPlatform(value: string) {
-    Object.defineProperty(process, "platform", { value, writable: true });
-  }
-
-  afterEach(() => {
-    setPlatform(originalPlatform);
-  });
-
-  test("returns the path when it already exists", async () => {
-    const { executableExists } = await loadExecutableModule();
-    const exists = vi.fn((candidate: string) => candidate === "/usr/local/bin/codex");
+  test("returns the path when it already exists", () => {
+    const exists = (candidate: string) => candidate === "/usr/local/bin/codex";
 
     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", async () => {
-    setPlatform("win32");
-    const { executableExists } = await loadExecutableModule();
-    const exists = vi.fn((candidate: string) => candidate === "C:\\tools\\codex.cmd");
+  test("on Windows, falls back to .exe, .cmd, then .ps1 for extensionless paths", () => {
+    const originalPlatform = process.platform;
+    Object.defineProperty(process, "platform", { value: "win32", writable: true });
+    try {
+      const exists = (candidate: string) => candidate === "C:\\tools\\codex.cmd";
 
-    expect(executableExists("C:\\tools\\codex", exists)).toBe("C:\\tools\\codex.cmd");
+      expect(executableExists("C:\\tools\\codex", exists)).toBe("C:\\tools\\codex.cmd");
+    } finally {
+      Object.defineProperty(process, "platform", { value: originalPlatform, writable: true });
+    }
   });
 
-  test("returns null when no matching path exists", async () => {
-    const { executableExists } = await loadExecutableModule();
-    const exists = vi.fn(() => false);
-
-    expect(executableExists("/missing/codex", exists)).toBeNull();
+  test("returns null when no matching path exists", () => {
+    expect(executableExists("/missing/codex", () => false)).toBeNull();
   });
 });
 
@@ -222,71 +166,61 @@ describe("quoteWindowsCommand", () => {
     setPlatform(originalPlatform);
   });
 
-  test("quotes a Windows path with spaces", async () => {
+  test("quotes a Windows path with spaces", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("C:\\Program Files\\Anthropic\\claude.exe")).toBe(
       '"C:\\Program Files\\Anthropic\\claude.exe"',
     );
   });
 
-  test("does not double-quote an already-quoted path", async () => {
+  test("does not double-quote an already-quoted path", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand('"C:\\Program Files\\Anthropic\\claude.exe"')).toBe(
       '"C:\\Program Files\\Anthropic\\claude.exe"',
     );
   });
 
-  test("returns the command unchanged when there are no spaces", async () => {
+  test("returns the command unchanged when there are no spaces", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("C:\\nvm4w\\nodejs\\codex")).toBe("C:\\nvm4w\\nodejs\\codex");
   });
 
-  test("escapes ampersands", async () => {
+  test("escapes ampersands", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("feature&bugfix")).toBe("feature^&bugfix");
   });
 
-  test("escapes pipes", async () => {
+  test("escapes pipes", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("feature|bugfix")).toBe("feature^|bugfix");
   });
 
-  test("doubles percent signs", async () => {
+  test("doubles percent signs", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("100%")).toBe("100%%");
   });
 
-  test("escapes carets", async () => {
+  test("escapes carets", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("feature^bugfix")).toBe("feature^^bugfix");
   });
 
-  test("escapes multiple metacharacters", async () => {
+  test("escapes multiple metacharacters", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("build&(test|deploy)!<output>")).toBe(
       "build^&^(test^|deploy^)^!^<output^>",
     );
   });
 
-  test("quotes commands with spaces after escaping metacharacters", async () => {
+  test("quotes commands with spaces after escaping metacharacters", () => {
     setPlatform("win32");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("C:\\Program Files\\My Tool&Stuff\\run 100%.cmd")).toBe(
       '"C:\\Program Files\\My Tool^&Stuff\\run 100%%.cmd"',
     );
   });
 
-  test("returns the command unchanged on non-Windows platforms", async () => {
+  test("returns the command unchanged on non-Windows platforms", () => {
     setPlatform("darwin");
-    const { quoteWindowsCommand } = await loadExecutableModule();
     expect(quoteWindowsCommand("/usr/local/bin/claude code")).toBe("/usr/local/bin/claude code");
   });
 });
@@ -302,31 +236,27 @@ describe("quoteWindowsArgument", () => {
     setPlatform(originalPlatform);
   });
 
-  test("quotes a Windows argument with spaces", async () => {
+  test("quotes a Windows argument with spaces", () => {
     setPlatform("win32");
-    const { quoteWindowsArgument } = await loadExecutableModule();
     expect(quoteWindowsArgument("C:\\Program Files\\Anthropic\\cli.js")).toBe(
       '"C:\\Program Files\\Anthropic\\cli.js"',
     );
   });
 
-  test("does not double-quote an already-quoted argument", async () => {
+  test("does not double-quote an already-quoted argument", () => {
     setPlatform("win32");
-    const { quoteWindowsArgument } = await loadExecutableModule();
     expect(quoteWindowsArgument('"C:\\Program Files\\Anthropic\\cli.js"')).toBe(
       '"C:\\Program Files\\Anthropic\\cli.js"',
     );
   });
 
-  test("returns the argument unchanged when there are no spaces", async () => {
+  test("returns the argument unchanged when there are no spaces", () => {
     setPlatform("win32");
-    const { quoteWindowsArgument } = await loadExecutableModule();
     expect(quoteWindowsArgument("--version")).toBe("--version");
   });
 
-  test("returns the argument unchanged on non-Windows platforms", async () => {
+  test("returns the argument unchanged on non-Windows platforms", () => {
     setPlatform("darwin");
-    const { quoteWindowsArgument } = await loadExecutableModule();
     expect(quoteWindowsArgument("/usr/local/bin/claude code")).toBe("/usr/local/bin/claude code");
   });
 });

packages/server/src/utils/executable.ts

@@ -1,54 +1,100 @@
-import { execFile } from "node:child_process";
+import { spawn, type ChildProcess } from "node:child_process";
+import { createRequire } from "node:module";
 import { existsSync } from "node:fs";
-import path, { extname } from "node:path";
-import { promisify } from "node:util";
+import { extname } from "node:path";
 
-const execFileAsync = promisify(execFile);
+type Which = (command: string, options: { all: true }) => Promise<string[]>;
 
-function pickBestWindowsCandidate(lines: string[]): string | null {
-  const candidates = lines.filter((line) => line.length > 0);
-  if (candidates.length === 0) return null;
+const require = createRequire(import.meta.url);
+const which = require("which") as Which;
+const PROBE_TIMEOUT_MS = 2000;
 
-  const extPriority = [".exe", ".cmd", ".ps1"];
-  for (const ext of extPriority) {
-    const match = candidates.find((candidate) => candidate.toLowerCase().endsWith(ext));
-    if (match) return match;
-  }
-
-  return candidates[0] ?? null;
+function hasPathSeparator(value: string): boolean {
+  return value.includes("/") || value.includes("\\");
 }
 
-function resolveExecutableFromWhichOutput(
-  name: string,
-  output: string,
-  source: "which",
-): string | null {
-  const lines = output
-    .split(/\r?\n/)
-    .map((line) => line.trim())
-    .filter((line) => line.length > 0);
-  const candidate = lines.at(-1);
-
-  if (!candidate) {
-    return null;
+async function enumerateCandidates(name: string): Promise<string[]> {
+  let candidates: string[];
+  try {
+    candidates = await which(name, { all: true });
+  } catch (error) {
+    // `which` throws ENOENT when the command is absent from PATH.
+    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
+      return [];
+    }
+    throw error;
   }
 
-  if (!path.isAbsolute(candidate)) {
-    console.warn(
-      `[findExecutable] Ignoring non-absolute ${source} output for '${name}': ${JSON.stringify(candidate)}`,
-    );
-    return null;
-  }
+  const seen = new Set<string>();
+  return candidates.filter((candidate) => {
+    if (seen.has(candidate)) {
+      return false;
+    }
+    seen.add(candidate);
+    return true;
+  });
+}
 
-  return candidate;
+function isWindowsCommandScript(executablePath: string): boolean {
+  const extension = extname(executablePath).toLowerCase();
+  return process.platform === "win32" && (extension === ".cmd" || extension === ".bat");
+}
+
+async function probeExecutable(executablePath: string): Promise<boolean> {
+  return await new Promise((resolve) => {
+    let settled = false;
+    let started = false;
+    let timer: ReturnType<typeof setTimeout> | undefined;
+
+    const settle = (result: boolean) => {
+      if (settled) {
+        return;
+      }
+      settled = true;
+      if (timer) {
+        clearTimeout(timer);
+      }
+      resolve(result);
+    };
+
+    let child: ChildProcess;
+    try {
+      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;
+    }
+
+    timer = setTimeout(() => {
+      if (started) {
+        child.kill();
+        settle(true);
+        return;
+      }
+      settle(false);
+    }, PROBE_TIMEOUT_MS);
+    timer.unref?.();
+
+    child.once("spawn", () => {
+      started = true;
+    });
+    child.once("error", () => {
+      // ENOENT/EACCES/EPERM/UNKNOWN here means the OS could not start the candidate.
+      settle(started);
+    });
+    child.once("exit", () => {
+      settle(started);
+    });
+  });
 }
 
 /**
- * On Unix we use `which`. On Windows we use `where.exe`.
- *
- * Both rely on the inherited process.env.PATH — on macOS/Linux, Electron
- * enriches it at startup via inheritLoginShellEnv(); on Windows, Electron
- * inherits the full user environment from Explorer.
+ * Check a literal executable path. PATH search is handled by findExecutable().
  */
 export function executableExists(
   executablePath: string,
@@ -70,35 +116,18 @@ export async function findExecutable(name: string): Promise<string | null> {
     return null;
   }
 
-  if (trimmed.includes("/") || trimmed.includes("\\")) {
-    return executableExists(trimmed);
+  if (hasPathSeparator(trimmed)) {
+    return (await probeExecutable(trimmed)) ? trimmed : null;
   }
 
-  if (process.platform === "win32") {
-    try {
-      const { stdout } = await execFileAsync("where.exe", [trimmed], {
-        encoding: "utf8",
-        windowsHide: true,
-      });
-      return (
-        pickBestWindowsCandidate(
-          stdout
-            .trim()
-            .split(/\r?\n/)
-            .map((line) => line.trim()),
-        ) ?? null
-      );
-    } catch {
-      return null;
+  const candidates = await enumerateCandidates(trimmed);
+  for (const candidate of candidates) {
+    if (await probeExecutable(candidate)) {
+      return candidate;
     }
   }
 
-  try {
-    const { stdout } = await execFileAsync("which", [trimmed], { encoding: "utf8" });
-    return resolveExecutableFromWhichOutput(trimmed, stdout.trim(), "which");
-  } catch {
-    return null;
-  }
+  return null;
 }
 
 export async function isCommandAvailable(command: string): Promise<boolean> {

packages/server/src/utils/git-rev-parse-path.ts

@@ -0,0 +1,25 @@
+import { resolve } from "node:path";
+
+export function parseGitRevParsePath(stdout: string): string | null {
+  const trimmed = stdout.trim();
+  if (!trimmed) {
+    return null;
+  }
+
+  const lines = trimmed.split(/\r?\n/);
+  if (lines.length !== 1) {
+    return null;
+  }
+
+  const path = lines[0]?.trim() ?? "";
+  if (!path || path.startsWith("--")) {
+    return null;
+  }
+
+  return path;
+}
+
+export function resolveGitRevParsePath(cwd: string, stdout: string): string | null {
+  const parsed = parseGitRevParsePath(stdout);
+  return parsed ? resolve(cwd, parsed) : null;
+}

packages/server/src/utils/worktree.ts

@@ -18,6 +18,7 @@ import {
 import { runGitCommand } from "./run-git-command.js";
 import { resolvePaseoHome } from "../server/paseo-home.js";
 import { ensureNodePtySpawnHelperExecutableForCurrentPlatform } from "../terminal/terminal.js";
+import { parseGitRevParsePath, resolveGitRevParsePath } from "./git-rev-parse-path.js";
 
 interface PaseoConfig {
   worktree?: {
@@ -529,14 +530,11 @@ async function inferRepoRootPathFromWorktreePath(worktreePath: string): Promise<
   } catch {
     // Fallback: best-effort resolve toplevel (will be the worktree root in typical cases)
     try {
-      const { stdout } = await runGitCommand(
-        ["rev-parse", "--path-format=absolute", "--show-toplevel"],
-        {
-          cwd: worktreePath,
-          env: READ_ONLY_GIT_ENV,
-        },
-      );
-      const topLevel = stdout.trim();
+      const { stdout } = await runGitCommand(["rev-parse", "--show-toplevel"], {
+        cwd: worktreePath,
+        env: READ_ONLY_GIT_ENV,
+      });
+      const topLevel = parseGitRevParsePath(stdout);
       if (topLevel) {
         return normalizePathForOwnership(topLevel);
       }
@@ -716,14 +714,11 @@ export async function runWorktreeTeardownCommands(options: {
  * This is where refs, objects, etc. are stored.
  */
 export async function getGitCommonDir(cwd: string): Promise<string> {
-  const { stdout } = await runGitCommand(
-    ["rev-parse", "--path-format=absolute", "--git-common-dir"],
-    {
-      cwd,
-      env: READ_ONLY_GIT_ENV,
-    },
-  );
-  const commonDir = stdout.trim();
+  const { stdout } = await runGitCommand(["rev-parse", "--git-common-dir"], {
+    cwd,
+    env: READ_ONLY_GIT_ENV,
+  });
+  const commonDir = resolveGitRevParsePath(cwd, stdout);
   if (!commonDir) {
     throw new Error("Not in a git repository");
   }
@@ -983,15 +978,11 @@ export async function resolvePaseoWorktreeRootForCwd(
 
   let worktreeRoot: string | null = null;
   try {
-    const { stdout } = await runGitCommand(
-      ["rev-parse", "--path-format=absolute", "--show-toplevel"],
-      {
-        cwd,
-        env: READ_ONLY_GIT_ENV,
-      },
-    );
-    const trimmed = stdout.trim();
-    worktreeRoot = trimmed.length > 0 ? trimmed : null;
+    const { stdout } = await runGitCommand(["rev-parse", "--show-toplevel"], {
+      cwd,
+      env: READ_ONLY_GIT_ENV,
+    });
+    worktreeRoot = parseGitRevParsePath(stdout);
   } catch {
     worktreeRoot = null;
   }