fix: start bun daemon children through nohup

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Support `mcporter list server.tool --schema` to print a single tool's schema instead of the whole server. (Issue #116)
 - Surface MCP server `instructions` from the initialize response in single-server `mcporter list` text and JSON output. (Issue #76)
 - Add compact `mcporter list <server> --brief` / `--signatures` output for scanning signatures without doc blocks, examples, or schemas. (PR #144, thanks @yuhp)
+- Launch Bun-compiled macOS daemon children through `nohup` so Homebrew binaries can start keep-alive daemons in the background on macOS 26. (Issue #66)
 
 ### Config
 

docs/daemon.md

@@ -47,6 +47,7 @@ read_when:
 ## Lifecycle & Fault Handling
 
 - **Auto start:** First call requiring the daemon triggers a lightweight bootstrap (fork/exec via `child_process.spawn` inside the CLI). We ensure the original command waits for the socket to become available (with a short timeout).
+- **macOS Bun binaries:** Homebrew/Bun-compiled binaries wrap the detached child launch with `nohup` so the background daemon survives the parent CLI exit on macOS 26.
 - **Auto restart:** The client shim treats `ECONNREFUSED`/broken pipe as a signal that the daemon died. It retries once by re-launching the daemon before surfacing the error.
 - **Idle timeout:** Each keep-alive server can specify `idleTimeoutMs` (default `null` = never). The daemon tracks last activity timestamps and auto-closes transports (and associated external processes) after the idle window. A global `daemonIdleTimeoutMs` can shut down the entire daemon after long inactivity.
 - **Logging:** Daemon writes structured logs under `~/.mcporter/logs/daemon.log` plus per-server logs for STDIO stderr so users can debug crashing servers.

src/daemon/launch.ts

@@ -10,11 +10,44 @@ export interface DaemonLaunchOptions {
   readonly extraArgs?: string[];
 }
 
+interface DaemonLaunchProcessInfo {
+  readonly argvEntry?: string;
+  readonly env: NodeJS.ProcessEnv;
+  readonly execArgv: string[];
+  readonly execPath: string;
+  readonly platform: NodeJS.Platform;
+}
+
+interface DaemonLaunchInvocation {
+  readonly command: string;
+  readonly args: string[];
+  readonly env: NodeJS.ProcessEnv;
+}
+
 export function launchDaemonDetached(options: DaemonLaunchOptions): void {
-  const cliEntry = resolveCliEntry();
+  const invocation = buildDaemonLaunchInvocation(options);
+  const child = spawn(invocation.command, invocation.args, {
+    detached: true,
+    stdio: 'ignore',
+    env: invocation.env,
+  });
+  child.unref();
+}
+
+export function buildDaemonLaunchInvocation(
+  options: DaemonLaunchOptions,
+  processInfo: DaemonLaunchProcessInfo = {
+    argvEntry: process.argv[1],
+    env: process.env,
+    execArgv: process.execArgv,
+    execPath: process.execPath,
+    platform: process.platform,
+  }
+): DaemonLaunchInvocation {
+  const cliEntry = resolveCliEntry(processInfo.argvEntry);
   const configArgs = options.configExplicit ? ['--config', options.configPath] : [];
   const args = [
-    ...process.execArgv,
+    ...processInfo.execArgv,
     ...(cliEntry ? [cliEntry] : []),
     ...configArgs,
     ...(options.rootDir ? ['--root', options.rootDir] : []),
@@ -23,21 +56,31 @@ export function launchDaemonDetached(options: DaemonLaunchOptions): void {
     '--foreground',
     ...(options.extraArgs ?? []),
   ];
-  const child = spawn(process.execPath, args, {
-    detached: true,
-    stdio: 'ignore',
-    env: {
-      ...process.env,
-      MCPORTER_DAEMON_CHILD: '1',
-      MCPORTER_DAEMON_SOCKET: options.socketPath,
-      MCPORTER_DAEMON_METADATA: options.metadataPath,
-    },
-  });
-  child.unref();
+  const env = {
+    ...processInfo.env,
+    MCPORTER_DAEMON_CHILD: '1',
+    MCPORTER_DAEMON_SOCKET: options.socketPath,
+    MCPORTER_DAEMON_METADATA: options.metadataPath,
+  };
+  if (shouldWrapDetachedLaunchWithNohup(processInfo.platform, cliEntry)) {
+    return {
+      command: 'nohup',
+      args: [processInfo.execPath, ...args],
+      env,
+    };
+  }
+  return {
+    command: processInfo.execPath,
+    args,
+    env,
+  };
 }
 
-function resolveCliEntry(): string | undefined {
-  const entry = process.argv[1];
+function shouldWrapDetachedLaunchWithNohup(platform: NodeJS.Platform, cliEntry: string | undefined): boolean {
+  return platform === 'darwin' && cliEntry === undefined;
+}
+
+function resolveCliEntry(entry = process.argv[1]): string | undefined {
   if (!entry) {
     throw new Error('Unable to resolve mcporter entry script.');
   }

tests/daemon-launch.test.ts

@@ -0,0 +1,80 @@
+import path from 'node:path';
+import { describe, expect, it } from 'vitest';
+import { buildDaemonLaunchInvocation, type DaemonLaunchOptions } from '../src/daemon/launch.js';
+
+const options: DaemonLaunchOptions = {
+  configPath: '/tmp/mcporter/config.json',
+  configExplicit: true,
+  rootDir: '/tmp/project',
+  socketPath: '/tmp/mcporter/daemon.sock',
+  metadataPath: '/tmp/mcporter/daemon.json',
+  extraArgs: ['--log-file', '/tmp/mcporter/daemon.log'],
+};
+
+describe('buildDaemonLaunchInvocation', () => {
+  it('launches Node entrypoints directly with the CLI script path', () => {
+    const invocation = buildDaemonLaunchInvocation(options, {
+      argvEntry: '/repo/dist/cli.js',
+      env: { PATH: '/usr/bin' },
+      execArgv: ['--enable-source-maps'],
+      execPath: '/usr/local/bin/node',
+      platform: 'darwin',
+    });
+
+    expect(invocation.command).toBe('/usr/local/bin/node');
+    expect(invocation.args).toEqual([
+      '--enable-source-maps',
+      path.resolve('/repo/dist/cli.js'),
+      '--config',
+      '/tmp/mcporter/config.json',
+      '--root',
+      '/tmp/project',
+      'daemon',
+      'start',
+      '--foreground',
+      '--log-file',
+      '/tmp/mcporter/daemon.log',
+    ]);
+    expect(invocation.env.MCPORTER_DAEMON_CHILD).toBe('1');
+    expect(invocation.env.MCPORTER_DAEMON_SOCKET).toBe('/tmp/mcporter/daemon.sock');
+    expect(invocation.env.MCPORTER_DAEMON_METADATA).toBe('/tmp/mcporter/daemon.json');
+  });
+
+  it('wraps compiled Bun binaries with nohup on macOS so detached self-spawn survives Tahoe', () => {
+    const invocation = buildDaemonLaunchInvocation(options, {
+      argvEntry: '/$bunfs/root/mcporter',
+      env: { PATH: '/usr/bin' },
+      execArgv: [],
+      execPath: '/opt/homebrew/bin/mcporter',
+      platform: 'darwin',
+    });
+
+    expect(invocation.command).toBe('nohup');
+    expect(invocation.args).toEqual([
+      '/opt/homebrew/bin/mcporter',
+      '--config',
+      '/tmp/mcporter/config.json',
+      '--root',
+      '/tmp/project',
+      'daemon',
+      'start',
+      '--foreground',
+      '--log-file',
+      '/tmp/mcporter/daemon.log',
+    ]);
+    expect(invocation.env.MCPORTER_DAEMON_CHILD).toBe('1');
+  });
+
+  it('keeps non-macOS compiled launches on the direct exec path', () => {
+    const invocation = buildDaemonLaunchInvocation(options, {
+      argvEntry: '/$bunfs/root/mcporter',
+      env: {},
+      execArgv: [],
+      execPath: '/usr/local/bin/mcporter',
+      platform: 'linux',
+    });
+
+    expect(invocation.command).toBe('/usr/local/bin/mcporter');
+    expect(invocation.args[0]).toBe('--config');
+  });
+});