[BUG]

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?

Bug: Claude Code processes become orphaned when terminal is closed

What Should Happen?

Bug: Claude Code processes become orphaned when terminal is closed

Environment:

• OS: Ubuntu 24.04.1 (SlimbookOS)
• Terminal: gnome-terminal, VS Code integrated terminal
• Claude Code: latest version

Description:
Claude Code processes do not terminate when the parent terminal is closed. Instead, they become orphaned and get adopted by systemd --user (PID 1 equivalent for user session).

Observed behavior:

• Closed terminal windows containing active Claude sessions
• Claude processes continued running with TTY showing ? (no terminal)
• Processes consumed significant CPU (up to 77%) despite having no terminal attached
• One process ran for 23+ hours after its terminal was closed

Expected behavior:
Claude Code should receive SIGHUP when the terminal closes and terminate gracefully, or at minimum, stop active work when it detects the terminal is gone.

Process evidence:
PID PPID STAT TTY CMD
583993 563118 Sl ? claude (ran 23 hours without terminal)
921216 563118 Sl ? claude (consuming 77% CPU without terminal)

Parent PID 563118 was systemd --user, indicating the processes were orphaned and reparented.

Impact:

• High CPU usage from zombie sessions
• Excessive heat/fan noise on laptops
• Users unaware that closing terminal doesn't stop Claude

Suggested fix:
Claude Code should monitor for terminal disconnect (SIGHUP) or periodically check if stdin/stdout are still valid, and gracefully exit when detached.

Error Messages/Logs

Steps to Reproduce

na

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.12

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_