spawn pgrep ENOENT crash on macOS

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description

Claude Code crashes with spawn pgrep ENOENT error during normal operation. The crash occurs when Claude Code's internal process management attempts to use pgrep -P <pid> to track child processes, but pgrep is not available in the sandboxed environment's PATH.

Environment

• OS: macOS (darwin)
• Claude Code Version: Latest (as of 2025-12-21)
• Model: claude-opus-4-5-20251101

Error Message

Error: spawn pgrep ENOENT
at ChildProcess._handle.onexit (node:internal/child_process:286:19)
at onErrorNT (node:internal/child_process:484:16)
at process.processTicksAndRejections (node:internal/process/task_queues:90:21) {
errno: -2,
code: 'ENOENT',
syscall: 'spawn pgrep',
path: 'pgrep',
spawnargs: [ '-P', 18164 ]
}

Steps to Reproduce

1. Start a Claude Code session on macOS
2. Perform various operations (the exact trigger is unclear, but appears related to process management)
3. Claude Code crashes with the above error

Expected Behavior

Claude Code should either:

1. Use a pgrep alternative that works in the sandboxed environment (e.g., ps aux | grep)
2. Gracefully handle the case where pgrep is unavailable
3. Include pgrep in the sandbox PATH if it's required

Actual Behavior

Claude Code crashes immediately when attempting to spawn pgrep, terminating the session and losing work in progress.

Additional Context

• macOS has pgrep at /usr/bin/pgrep, but Claude Code's sandboxed environment appears to not have access to it
• The spawnargs: [ '-P', 18164 ] suggests Claude Code is trying to find child processes of a specific PID
• This is an internal Claude Code operation, not triggered by user bash commands
• The crash is intermittent but reproducible across multiple sessions

Workaround

None available for the internal crash. Users can avoid running pgrep as a bash command (which also fails), but the internal process management crash cannot be prevented from the user side.

Suggested Fix

Replace internal pgrep -P <pid> calls with a cross-platform alternative:
// Instead of: spawn('pgrep', ['-P', pid])
// Use: spawn('ps', ['-o', 'pid=', '--ppid', pid]) // Linux
// Or: spawn('ps', ['-o', 'pid=', '-g', pid]) // macOS

Or wrap the pgrep call in a try-catch with fallback logic.

What Should Happen?

Workaround

None available for the internal crash. Users can avoid running pgrep as a bash command (which also fails), but the internal process management crash cannot be prevented from the user side.

Suggested Fix

Replace internal pgrep -P <pid> calls with a cross-platform alternative:
// Instead of: spawn('pgrep', ['-P', pid])
// Use: spawn('ps', ['-o', 'pid=', '--ppid', pid]) // Linux
// Or: spawn('ps', ['-o', 'pid=', '-g', pid]) // macOS

Or wrap the pgrep call in a try-catch with fallback logic.

Error Messages/Logs

crash; exit to terminal

Steps to Reproduce

Steps to Reproduce

1. Start a Claude Code session on macOS
2. Perform various operations (the exact trigger is unclear, but appears related to process management)
3. Claude Code crashes with the above error

Expected Behavior

Claude Code should either:

1. Use a pgrep alternative that works in the sandboxed environment (e.g., ps aux | grep)
2. Gracefully handle the case where pgrep is unavailable
3. Include pgrep in the sandbox PATH if it's required

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.75

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_