---
id: M07-L04
title: "Build the review skill and handoff"
module: M07
chapters: "16"
checkpoint: "CP08"
---

# M07-L04 — Build the review skill and handoff

Evaluate the second skill and write a handoff that another session can use. CP08 contains `.agents/skills/firmware-review/SKILL.md`, normal/fault source, and basic tests. Keep the review bounded to an exact diff and applicable requirements.

The skill should inspect timing, invalid/stale/recovery paths, bounds, conversions, and relevant tests. A finding needs a file/location, concrete trigger, consequence, and supporting test or source. It should distinguish a prediction from executed evidence and should not invent findings when the change is clean.

For the defect case, stay in a CP08 checkout cloned from the supplied history bundle so the review skill is available. Inspect the bounded supplied fault diff:

```powershell
git diff CP07 FAULT-stale -- firmware/sensor-monitor/monitor_policy.cpp
```

Ask for review without repair. The defect disables stale expiration; at 4001 milliseconds, a last sample from 1000 must be unavailable. Verify any claimed finding against the requirement. Run the faulty behavior only in a separate FAULT-stale exercise copy, preserving CP08.

Also review a consistent local-variable rename, then run an unrelated README sentence edit in a fresh task without naming the skill. Correct restraint matters: a clean change should not require invented correctness findings, and unrelated prose should not force a firmware audit.

Write the handoff with active source, completed change, actual receipts, open questions, and one bounded next action. CP08's supplied next task adds a negative-infinity assertion without changing production behavior. If you already added it while extending Chapter 15, use a fresh CP08 copy for the reproducible restart exercise rather than duplicating the assertion.

## Resources and completion

Read Chapter 16 and the matching Sensor Monitor checkpoint README, requirements, and evidence notes. Project paths are relative to its root. Figures: SS16-01, SS16-02, SS16-03. Attempt the [exercise](exercise.md), preserve actual results, then use the separate instructor answer key. 

Source resources: [Chapter 16](../../../../book/chapters/ch16/chapter.md); [checkpoint and recovery map](../../../../examples/sensor-monitor/docs/checkpoints.md). Use the README and requirements inside your named checkpoint; the repository's final CP09 files include features absent from earlier stages.