Root cause: Child claude hangs at startup when global settings containing
hooks (SessionStart, SessionEnd, etc.) are inherited despite creating a
temp settings.json with only a Stop hook.
When --settings=<temp_path> is passed without --setting-sources=, Claude Code
merges temp settings with global settings. Global hooks fire and may hang,
causing the child to never produce output and the first-output timeout to fire.
Fix: Always pass --setting-sources= to child claude (src/session.rs:127-129)
to prevent global settings inheritance. This ensures ONLY the temp settings.json
is loaded, preventing any global hooks from causing hangs.
Evidence: Documented in notes/bf-2u1-findings.md and notes/bf-2u1-investigation.md
Related beads:
- bf-2w7: temp dir and FIFO cleanup
- bf-3ag: session implementation
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