Session freezes on 'Osmosing' after completing task - unresponsive for 5+ hours

Summary

Claude Code session became completely unresponsive after completing a PR merge, displaying "Osmosing…" spinner for over 5 hours with no response to user input.

Steps to Reproduce

1. Had active session performing git/GitHub operations
2. Merged PR using gh pr merge --squash --delete-branch
3. Ran git checkout main && git pull
4. Session completed those commands successfully
5. Session then froze on "Osmosing…" indefinitely

Expected Behavior

Session should return to interactive prompt after completing commands.

Actual Behavior

• Spinner showed "Osmosing… (esc to interrupt · 5h 46m 45s · ↓ 0 tokens)"
• Multiple user inputs ignored ("Are you ok?", "Ok whats next", etc.)
• Session never recovered
• Had to kill the terminal

Possibly Related

Similar to #19060 (CLI freezes and never recovers) but:

• No "No messages returned" error displayed
• Interactive mode, not automated script
• Happened after successful command completion

Environment

| Component | Version |
|-----------|---------|
| Claude Code | 2.1.19 |
| macOS | Darwin 25.2.0 |
| Platform | Apple Silicon |

Debug Log

Will attach debug log from ~/.claude/debug/ in comments.