Claude CLI processes not terminating when terminal closes

Description

Claude CLI processes continue running after the user closes or disconnects from the terminal, leading to significant memory accumulation over time.

Observed Behavior

• User closes terminal tab, Ctrl+C, or terminal disconnects
• Claude process continues running in background as orphan
• Process holds onto memory (600MB-3GB per session)
• Over days/weeks, multiple orphaned sessions accumulate

Evidence

On a system running for ~2 weeks, found 11 orphaned Claude sessions consuming ~10GB RAM:

PID: 1729372 | TTY: pts/27 | Started: Jan19 | Mem: 0.7%
PID: 1895002 | TTY: ? | Started: Jan20 | Mem: 0.4%
PID: 3047777 | TTY: ? | Started: Jan21 | Mem: 0.5%
PID: 3502757 | TTY: pts/12 | Started: Jan22 | Mem: 3.0%
PID: 3543434 | TTY: pts/13 | Started: Jan22 | Mem: 2.3%
PID: 3601287 | TTY: pts/21 | Started: Jan22 | Mem: 2.1%
PID: 3787540 | TTY: ? | Started: Jan23 | Mem: 1.6%
PID: 3955594 | TTY: pts/49 | Started: Jan22 | Mem: 1.4%
PID: 3959187 | TTY: pts/50 | Started: Jan22 | Mem: 2.4%
PID: 3960252 | TTY: pts/51 | Started: Jan22 | Mem: 0.9%
PID: 3963043 | TTY: ? | Started: Jan22 | Mem: 0.9%

Processes with TTY: ? had already lost their controlling terminal but were still running.

Expected Behavior

When the controlling terminal is closed or sends SIGHUP, the Claude process should:

1. Detect the terminal disconnection
2. Clean up resources
3. Terminate gracefully

Environment

• OS: Linux 6.14.0-37-generic
• Claude CLI version: 2.1.17

Workaround

Users can manually clean up with:

pkill -f "claude"

Or check for orphaned processes:

pgrep -a claude

Suggested Fix

Implement proper signal handling for:

• SIGHUP (terminal hangup)
• SIGPIPE (broken pipe)
• Monitor stdin/tty availability and exit if lost