claude-code - 💡(How to fix) Fix Claude desktop leaks PTY file descriptors, exhausting system PTY limit

Summary

The Claude desktop app leaks PTY (pseudo-terminal) master file descriptors over time. Each bash tool call opens /dev/ptmx but the handles are never closed when the session ends. This causes the system-wide PTY pool to be exhausted, breaking other terminal applications.

Impact

• Ghostty fails to open new terminal windows with: "Your system cannot allocate any more pty devices."
• Zellij fails to start with: "could not enable raw mode: Os { code: 6, kind: Uncategorized, message: "Device not configured" }"
• Any app that requires PTY allocation is affected.

Reproduction

Use Claude desktop with the bash tool across multiple sessions/conversations over time. The PTY count grows monotonically.

Evidence

$ lsof 2>/dev/null | grep "ptmx" | awk '{print $1, $2}' | sort | uniq -c | sort -rn | head -5
 513 Claude 60807     ← nearly all PTYs consumed by Claude desktop
   3 wezterm-g 99670
   3 Safari 14780
   ...

$ sysctl kern.tty.ptmx_max
kern.tty.ptmx_max: 511

513 open PTY masters in a single Claude process against a system limit of 511.

Workaround

Quit and relaunch the Claude desktop app to release all leaked handles.

Environment

• macOS Darwin 25.4.0 (Apple Silicon, J614s)
• Claude desktop version: 2.1.136
• Ghostty version: reported in error message