/stuck — diagnose frozen/slow Claude Code sessions

The user thinks another Claude Code session on this machine is frozen, stuck, or very slow. Investigate and post a report to #claude-code-feedback.

What to look for

Scan for other Claude Code processes (excluding the current one — PID is in process.pid but for shell commands just exclude the PID you see running this prompt). Process names are typically claude (installed) or cli (native dev build).

Signs of a stuck session:

• High CPU (≥90%) sustained — likely an infinite loop. Sample twice, 1-2s apart, to confirm it's not a transient spike.
• Process state D (uninterruptible sleep) — often an I/O hang. The state column in ps output; first character matters (ignore modifiers like +, s, <).
• Process state T (stopped) — user probably hit Ctrl+Z by accident.
• Process state Z (zombie) — parent isn't reaping.
• Very high RSS (≥4GB) — possible memory leak making the session sluggish.
• Stuck child process — a hung git, node, or shell subprocess can freeze the parent. Check pgrep -lP <pid> for each session.

Investigation steps

1. List all Claude Code processes (macOS/Linux):

   ps -axo pid=,pcpu=,rss=,etime=,state=,comm=,command= | grep -E '(claude|cli)' | grep -v grep

   Filter to rows where comm is claude or (cli AND the command path contains "claude").

2. For anything suspicious, gather more context:

   • Child processes: pgrep -lP <pid>
   • If high CPU: sample again after 1-2s to confirm it's sustained
   • If a child looks hung (e.g., a git command), note its full command line with ps -p <child_pid> -o command=