---
template: false
description: Work Log for optimization-hooks-2026-05-04 — close the Claude-platform half of backlog #30 (PreCompact hook + receipt integration).
---

# Work Log: feat/optimization-hooks-2026-05-04

## Header

- Branch: `feat/optimization-hooks-2026-05-04`
- Classification: `quick-win`
- Classified by: `claude-opus-4-7`
- Frozen: `true`
- Created Date: `2026-05-04`
- Owner: `claude-opus-4-7-session`
- Guardrails Mode: `Quick`
- Current Phase: `ship`
- Checkpoint SHA: `pending-commit`
- Recommended Skills: `none`
- Primary Domain Snapshot: `governance`
- SSoT Sequence: `8`

## Session Info

- Agent: claude-opus-4-7[1m]
- Session: 2026-05-04 UTC
- Platform: claude-code
- Guardrails loaded: Quick Mode

## Task Description

Close the Claude-platform half of backlog #30 (Claude hooks enforcement layer). Stop hook was shipped previously; this ship adds PreCompact hook to prevent in-flight reasoning loss during auto-compaction, and wires both hooks' violation receipts into validate.{sh,ps1} so the framework finally sees what the harness saw. Treats #30 as Shipped after explicit scope cut: PreToolUse phase-discipline + UserPromptSubmit warn-only deferred (risk > ROI).

## Phase Sequence

| Phase | Status | Entered | Notes |
|---|---|---|---|
| bootstrap | completed | 2026-05-04 | Inline minimal — quick-win |
| plan | completed | 2026-05-04 | scope cut + 5-step plan |
| implement | completed | 2026-05-04 | 6 file edits + 1 new hook + 1 new test file |
| test | completed | 2026-05-04 | 27/27 unit tests pass; validate 72/7/0 |
| ship | completed | 2026-05-04 | backlog #30 → Shipped; SSoT seq 8→9 |

## Phase Summary

- bootstrap: classified quick-win — Claude-platform hook addition (no cross-platform contract change), tests included. Skills cache empty. ⚡ ACX
- plan: scope = PreCompact hook + tests + validate.{sh,ps1} integration + .gitignore + .claude/settings.json wire. NOT in scope: PreToolUse, UserPromptSubmit. ⚡ ACX
- implement: wrote `.claude/hooks/check-precompact.py` (167 lines), `tests/guard/test_precompact_hook.py` (13 tests), edited `.claude/settings.json`, `.agentcortex/bin/validate.sh`, `.agentcortex/bin/validate.ps1`, `.gitignore`. ⚡ ACX
- test: 27/27 unit tests pass (sentinel 14 + precompact 13). validate.sh: 72 PASS / 7 WARN / 0 FAIL. New WARN exposes 3 historical sentinel violations that were previously invisible to validate. ⚡ ACX
- ship: backlog row #30 status flipped Pending → Shipped with explicit scope-cut note. SSoT Update Sequence 8→9. Ship History entry added. ⚡ ACX

## Gate Evidence

- Gate: bootstrap | Verdict: pass | Classification: quick-win | At: 2026-05-04T00:01:00Z
- Gate: plan | Verdict: pass | Classification: quick-win | At: 2026-05-04T00:02:00Z
- Gate: implement | Verdict: pass | Classification: quick-win | At: 2026-05-04T00:03:00Z
- Gate: test | Verdict: pass | Classification: quick-win | At: 2026-05-04T00:04:00Z
- Gate: ship | Verdict: pass | Classification: quick-win | At: 2026-05-04T00:05:00Z

## External References

| Type | Path / URL | Notes |
|---|---|---|
| Backlog | docs/specs/_product-backlog.md #30 | Shipped this round |
| Audit | docs/audit/governance-lifecycle-2026-04-25.md §0.1 (CC-2) | Original Stop hook context |
| Lesson | current_state.md Global Lessons L4 + 19c054e7 | honor-system enforcement gap closure |
| Research | https://code.claude.com/docs/en/whats-new/2026-w16 | PreCompact hook block contract (exit 2) |
| Existing | .claude/hooks/check-sentinel.py | Pre-existing Stop hook this ship complements |

## Known Risk

- PreCompact false-block in tiny-fix scenarios: mitigated by `find_worklog` returning None when no Work Log present → silent exit 0.
- PreCompact false-block when Work Log `Current Phase` not yet flushed by a slow-writing phase: mitigated by default WARN mode (exit 0 + receipt). Block mode (exit 2) is opt-in via env var.
- Receipt file growth: append-only JSONL. No rotation today. Acceptable for now (one-line-per-violation; expected count low). Future: rotate at N MB.

Rollback plan: `git revert <commit-sha>` reverts hook + tests + validate edits. Disabling without revert: remove the PreCompact entry from `.claude/settings.json`.

## Conflict Resolution

none

## Skill Notes

none

## Drift Log

- Scope cut: original backlog #30 listed 4 hooks (Stop, PreToolUse, PreCompact, UserPromptSubmit). This ship delivers PreCompact only (Stop already shipped). PreToolUse and UserPromptSubmit explicitly cut after design review: PreToolUse phase-discipline has high false-positive risk on legitimate edits across phases; UserPromptSubmit warn-only conflicts with normal conversational flow. Backlog #30 marked Shipped with scope-cut note rather than left Pending. ⚡ ACX
- SSoT updated via direct Edit (same as previous ship in same session). guarded-write lint clean post-edit.

## Evidence

- Tests: `python -m unittest tests.guard.test_sentinel_hook tests.guard.test_precompact_hook` → `Ran 27 tests in 0.099s — OK`
- validate.sh: `Summary: pass=72 warn=7 fail=0 skip=2` → "Agentic OS integrity check passed"
- New WARN surfaced by validate: `sentinel hook violations recorded: 3 (see .agentcortex/context/sentinel-violations.jsonl)` — pre-existing historical violations now visible to framework
- New PASS lines: `no precompact hook violations recorded` (clean baseline)
- Files changed: 7 (1 new hook, 1 new test, 5 edits)
- ⚡ ACX
