Bug: preemptive-compaction hook built but never registered in hooks.json

[voravitl]

Summary

The preemptive-compaction hook is built and exists in dist/hooks/preemptive-compaction/index.js, but it is never registered in hooks/hooks.json under PostToolUse. This means the HUD context warning feature silently does nothing.

Root Cause

1. Not registered in hooks.json — the hook script exists in dist/ but no entry is added to hooks.json during build/install.
2. In-memory state doesn't work for shell hooks — the original createPreemptiveCompactionHook() uses an in-memory Map() to track accumulated token counts, but each hook invocation spawns a new process, so state is always lost. The hook would never reach its threshold.
3. Token estimation is unrealistic — the original hook only counts tool_response content characters ÷ 4 as token estimate. A single tool response would need to be 680k+ characters to trigger at 170k tokens — practically never happens.

Environment

• OMC version: 4.10.2
• Claude Code version: 2.1.90
• macOS (Darwin)

Workaround

I rewrote the hook to use the transcript-file approach (same as pre-tool-enforcer and context-guard-stop) — reading input_tokens and context_window from the transcript's last 4KB. This is accurate and works reliably across process boundaries.

Key changes:

• Reads transcript_path from stdin JSON (provided by Claude Code)
• Uses resolveTranscriptPath() for git worktree compatibility
• File-based cooldown (1 min per cwd in /tmp/) to prevent warning spam
• Warns at 70%, critical at 90%

Suggested Fix

Register the hook in hooks.json under PostToolUse and switch to transcript-based token reading instead of in-memory accumulation.

Would be happy to contribute a PR if helpful.

[Yeachan-Heo]

Confirmed — the hook is built in dist/hooks/preemptive-compaction/ but never registered in hooks/hooks.json. Clear reproducible bug, opening a fix session now.

(Side note: you're not currently starring any core repo — please consider starring oh-my-claudecode for future triage priority.)

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[repo owner's gaebal-gajae (clawdbot) 🦞]