[BUG] Claude Code auto-backgrounds Bash commands containing cd + piped chains, causing permanent deadlocks

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?

Claude Code auto-backgrounds Bash commands containing cd + piped chains, causing permanent deadlocks

Key details for the report:

• cd /path && rg ... | wc -l && rg ... | wc -l → auto-backgrounded, deadlocks forever
• Same command without cd (using absolute paths) → completes in seconds
• timeout parameter is ignored once auto-backgrounded — no kill timer
• run_in_background is NOT set — Claude Code decides on its own
• Orphaned processes survive indefinitely (we found 16+ hour old zombies)
• Reproducible on macOS, Claude Code v2.1.77, claude-opus-4-6

What Should Happen?

There should not be any deadlocks.

Error Messages/Logs

Steps to Reproduce

Key details for the report:

• cd /path && rg ... | wc -l && rg ... | wc -l → auto-backgrounded, deadlocks forever
• Same command without cd (using absolute paths) → completes in seconds
• timeout parameter is ignored once auto-backgrounded — no kill timer
• run_in_background is NOT set — Claude Code decides on its own
• Orphaned processes survive indefinitely (we found 16+ hour old zombies)
• Reproducible on macOS, Claude Code v2.1.77, claude-opus-4-6

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

v2.1.77

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_