release: v3.31.0 — Skills 2.0 taxonomy, evals, lifecycle

- §5.0 Two Kinds of Skills: Capability Uplift vs Encoded Preference
- §5.X Skill Lifecycle & Retirement: Catch Regressions + Spot Outgrowth
- §5.Y Skill Evals: Benchmark Mode, A/B Testing, Trigger Tuning
- Vitals + SE-CoVe community plugins documented (§8.5)
- Memory system: 3 corrections (Auto-Memories v2.1.59+, thresholds, WHAT/WHY/HOW)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/resource-evaluations/vitals-codebase-health-plugin.md

@@ -0,0 +1,95 @@
+# Resource Evaluation: Vitals — Codebase Health Plugin
+
+**Date**: 2026-03-06
+**Evaluator**: Claude (Sonnet 4.6) via /eval-resource
+**Source**: LinkedIn post (text) + GitHub repo
+**GitHub**: https://github.com/chopratejas/vitals
+**Author**: Tejas Chopra
+**Score**: 3/5 (Pertinent)
+**Decision**: Integrated into guide/ultimate-guide.md §8.5
+
+---
+
+## Summary
+
+Vitals is a Claude Code plugin (v0.1 alpha, MIT, Python stdlib + git) that identifies code hotspots using a composite metric: `git churn × structural complexity × coupling centrality`. Claude then reads the flagged files and provides semantic diagnosis rather than raw metrics.
+
+**Key points**:
+1. Computes churn × complexity × coupling centrality — no linter does this combination
+2. Claude reads top-flagged files: diagnosis says "this class handles routing, caching, rate limiting, AND metrics in 7,137 lines" not just "high complexity"
+3. Background tracking of AI-generated edits via PostToolUse hooks
+4. Zero dependencies, zero API keys — Python stdlib + git only
+5. v0.1 alpha: core detection works, trend tracking planned for v0.2+
+
+---
+
+## Evaluation Scoring
+
+| Criterion | Score | Notes |
+|-----------|-------|-------|
+| **Relevance** | 3/5 | Addresses real AI code quality problem, original approach |
+| **Originality** | 4/5 | churn×complexity×centrality not covered elsewhere in guide |
+| **Authority** | 2/5 | New author, v0.1 alpha, limited community validation |
+| **Accuracy** | 4/5 | Methodology sound; post had one misquoted stat (see fact-check) |
+| **Actionability** | 4/5 | Install + use in 2 commands |
+
+**Overall Score**: **3/5 (Pertinent)**
+
+---
+
+## Gap Analysis
+
+### Already Covered in Guide
+
+| Concept | Guide Coverage | Location |
+|---------|----------------|----------|
+| AI code quality degradation | GitClear stats, comprehension debt | quiz/questions, learning-with-ai.md |
+| Plugin system | Full section 8.5 | ultimate-guide.md:12015 |
+| SE-CoVe plugin example | Full documentation | examples/plugins/se-cove.md |
+
+### What's New
+
+- **Hotspot identification methodology**: `churn × complexity × coupling centrality` as a composite metric — not in guide
+- **Concrete tool** that maps the "AI code debt" problem to actionable file-level output
+- **Bus factor / knowledge risk** metric — unique angle not documented
+- **PostToolUse hook for AI provenance tracking** — interesting hook usage pattern
+
+---
+
+## Fact-Check Results
+
+| Claim | Verified | Note |
+|-------|----------|------|
+| "41% of code is now AI-generated" | ❌ INCORRECT | GitClear actual stat: AI code has **41% higher churn**, not 41% of code volume. Post misquotes the stat. |
+| "Refactoring collapsed from 25% to under 10%" | ✅ | GitClear 211M lines, 2021–2025, confirmed via Perplexity |
+| "GitClear's research on 211M lines" | ✅ | Confirmed |
+| "METR's RCT showed 20% faster perception, 19% slower reality" | ✅ | METR RCT (Jul 2025, 16 devs, 246 tasks): estimated +20-24%, actual -19% |
+| "Zero dependencies, Python stdlib + git" | ✅ | README confirms |
+| v0.1 alpha status | ✅ | README confirms |
+
+**Key correction**: The post's "41% of code is now AI-generated" is a misquote. The guide documents this correctly as "AI-generated code has 41% higher churn."
+
+---
+
+## Integration Actions
+
+1. ✅ Added "Featured Community Plugins" subsection to `guide/ultimate-guide.md` §8.5 (~line 12385)
+   - Vitals section with install commands, use cases
+   - SE-CoVe section (updated from existing coverage)
+   - Vitals vs. SE-CoVe comparison table
+2. ✅ Updated `machine-readable/reference.yaml` with Vitals entry (install, command, purpose, status)
+
+---
+
+## Metadata
+
+```yaml
+evaluated_by: Claude (Sonnet 4.6)
+skill_used: /eval-resource
+perplexity_used: Yes (fact-check GitClear + METR stats)
+changes_made:
+  - guide/ultimate-guide.md (§8.5 Featured Community Plugins)
+  - machine-readable/reference.yaml (plugins_vitals, plugins_se_cove_detail)
+  - docs/resource-evaluations/vitals-codebase-health-plugin.md (this file)
+integration_decision: Integrated (score 3/5)
+```