claude-agent-acp: unknown system subtypes (code_change_published / vcs_state_changed) hit unreachable() log noise in every session

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
javascript
Domain
tooling

Research direction

Start with utils.js:77 and the system subtype switch described in the issue. Read RESEARCH/BUZZ_VCS_SYSTEM_EVENTS_INVESTIGATION_2026_08_08.md for event context, then reproduce a Claude session with the watcher events. Done means code_change_published and vcs_state_changed no longer produce stderr error noise.

Written by the indexing model from the issue text.

Description

Summary

claude-agent-acp 0.62.0 logs unreachable() (utils.js:77) for unknown system subtypes, then break — the turn continues, but every code_change_published / vcs_state_changed event (injected by Buzz Desktop's watcher; see linked issue) produces stderr noise in every Claude session.

Ask

  • No-op code_change_published and vcs_state_changed in the system subtype switch, or
  • Downgrade unknown-system-subtype from error/unreachable to debug-level log

Not a respawn fix (context)

Removing this noise does not alone stop Broken pipe respawns — they correlate only weakly (e.g. Conductor log: 3 unexpected-case vs 10 respawns; also -32603 DeepSeek bridge errors on long turns). Multi-causal; this issue is scoped to the stderr flood only.

Reference

Investigation: RESEARCH/BUZZ_VCS_SYSTEM_EVENTS_INVESTIGATION_2026_08_08.md.

Dominant language
Rust
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Merged PRs (30d)
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