| name | observe |
| description | Measure cost and context before justifying any harness change (P7). Read /context, /cost, /status and the tool-failure log to get before/after numbers; roll back anything that worsens a metric. Use when adding tools, evaluating a phase, or diagnosing quota burn. |
Observe Skill (P7 — peak KPI = verified results / quota)
Purpose
No addition is justified by intuition. Every tool, skill, or hook must pay for itself in a measured metric; if a change worsens a number, revert it (P7).
Metrics to capture
| Metric | Source |
|---|
| Files read / task | session transcript count |
| Output tokens | /cost |
| Peak context fill % | /context |
| Message count | /cost, /status |
| Turn count | session |
| Retry rate | tool-failure log |
| Failure blast radius | files touched per failed change |
Workflow (per phase / per addition)
- Baseline — record metrics on a fixed sample task before the change.
- Change — apply one thing (a tool, a skill, a hook).
- After — re-run the same sample task, record metrics.
- Gate — any single metric regresses → roll back the change (git boundary).
Inputs
/context — token budget + peak fill./cost, /status — messages, output tokens.scripts/hooks/tool-failure-log.sh output — retries, failure patterns.
Rule
One change at a time, measured. Bundled changes hide which one regressed. Keep a short before/after note in HANDOFF.md (P5), not auto-injected.
Measured escalations (don't adopt by default)
Default memory is file-based (HANDOFF.md + .serena/memories). Only if a metric shows it's insufficient: claude-mem (auto session memory) — watch for auto-injection noise. Adopt via the before/after gate above, never preemptively (ADR-010/P7).
