Retrospective: Evolve Self-Testing Rules from Real Cases

Workflow

Step 1: Read Cases

Read .claude/skills/1k-retrospective/references/case-studies.md. Count cases since the last <!-- Retrospective completed --> marker. If fewer than 3 new cases, report "Not enough new cases" and stop.

Step 2: Analyze Patterns

For each case, extract root cause category and which self-testing section (1-8) could have caught it, or "NEW" if not covered. Aggregate counts per pattern.

Step 3: Identify Gaps and Weak Spots

• Gaps: patterns appearing 2+ times marked "NEW" → candidates for new check items
• Weak spots: patterns appearing 3+ times already covered → check item needs stronger wording or more specificity

Step 4: Propose Changes

Output a short report:

Retrospective — YYYY-MM-DD
Cases analyzed: N (date range: YYYY-MM-DD to YYYY-MM-DD)
Recurring patterns: [pattern] N (NEW/WEAK), [pattern] N (NEW/WEAK)
Proposed changes: Add [Section N] [one-line check] / Strengthen [Section N] [current → revised]
Housekeeping: archive candidates [list], zero-hit checks [list]

Step 5: Apply Changes (after user confirmation)

Rules when modifying self-testing.mdc:

1. Max 150 lines — if exceeded, consolidate similar items or move details to references/patterns.md
2. One-liner check items only — no code examples in the rule file
3. Keep 9-section structure — new items go into existing sections, no new sections
4. Never delete case entries — mark archived with [ARCHIVED] prefix

Step 6: Update Timestamp

Append to case-studies.md:

<!-- Retrospective completed: YYYY-MM-DD | Cases analyzed: N | Changes applied: N -->

Example

5 cases: 3 BigNumber (NaN/precision/division), 1 cleanup, 1 stale closure. → BigNumber = NEW (3 hits) → Add one-line check to Section 1.