Documentation Maintenance

🚨 CRITICAL: Use this skill BEFORE every PR to ensure documentation is up-to-date!

When to Use This Skill

MANDATORY before:

• Creating a pull request
• Committing significant changes
• After discovering a bug or gotcha
• After implementing a new feature
• After refactoring complex code

Proactive use:

• After fixing a non-obvious bug
• After discovering edge cases
• After learning manufacturer-specific quirks
• After debugging a test failure

Pre-PR Documentation Checklist

Use this checklist BEFORE running

/commit

✅ Step 1: Identify What Changed

Questions to ask:

• Did I add/modify a manufacturer handler? → Update

  /handler-pattern-design

• Did I work with MPN normalization? → Update

  /mpn-normalization

• Did I modify similarity calculators? → Update

  /similarity-calculator-architecture

• Did I add new component types? → Update

  /component-type-detection-hierarchy

• Did I add spec extraction logic? → Update

  /component-spec-extraction

• Did I convert a calculator to metadata? → Update

  /metadata-driven-similarity-conversion

• Did I modify manufacturer detection? → Update

  /manufacturer-detection-from-mpn

• Did I add equivalent groups? → Update

  /equivalent-group-identification

• Is this a cross-cutting change? → Update

  CLAUDE.md

✅ Step 2: Document Learnings & Quirks

Where to add learnings:

General/Cross-Cutting →

CLAUDE.md

Add to

## Learnings & Quirks

### Pattern Matching
- Handler detection order matters in `ComponentManufacturer.fromMPN()` - more specific patterns checked before generic

### Handler Implementation
- Always register patterns for both base type AND manufacturer-specific type

When to use CLAUDE.md:

• Cross-cutting patterns affecting multiple areas
• Build system quirks (Maven, dependencies)
• Testing patterns (JUnit, parameterized tests)
• Git workflow discoveries
• CI/CD issues

Component-Specific → Relevant Skill File

Example: Handler bug discovered

Update

.claude/skills/handler-pattern-design/SKILL.md

## Learnings & Quirks

### Package Extraction Edge Cases
- STM32F103C8**T6**: Package code is second-to-last char ('T'), not last ('6' is temp range)
- Position-based extraction requires normalization FIRST (hyphens break charAt())

Example: MPN normalization quirk

Update

.claude/skills/mpn-normalization/SKILL.md

### Unicode Handling
- Micro sign µ (U+00B5) becomes Greek MU Μ (U+039C) when uppercased
- Impact: CapacitorSimilarityCalculator.parseCapacitanceValue() must replace BEFORE uppercase

Which skill file to update:

/handler-pattern-design

/mpn-normalization

/similarity-calculator-architecture

/component-type-detection-hierarchy

/component-spec-extraction

/metadata-driven-similarity-conversion

/manufacturer-detection-from-mpn

/equivalent-group-identification

✅ Step 3: Update Examples & Code Snippets

If you fixed a bug, add the fix as an example:

### Common Anti-Patterns

| Anti-Pattern | Problem | Solution |
|-------------|---------|----------|
| **Using matches() instead of matchesForCurrentHandler()** | Cross-handler false matches | Use `patterns.matchesForCurrentHandler()` |

If you discovered a new pattern, document it:

### Suffix Ordering (New Pattern)

**Pattern: Check longer suffixes BEFORE shorter suffixes.**

```java
// ✅ CORRECT: Check "DT" before "T"
if (upperMpn.endsWith("DT")) return "SOT-223";
if (upperMpn.endsWith("T")) return "TO-220";

---

### ✅ Step 4: Update Tables & Lists

**If you converted a calculator to metadata:**

Update `/metadata-driven-similarity-conversion/SKILL.md`:

```markdown
| PassiveComponentCalculator | ✅ | #XXX | 2026-01-24 | value, tolerance, package | value |

If you added a manufacturer:

Update

/manufacturer-detection-from-mpn/SKILL.md

**Total manufacturers:** 121 (was 120+)

If you fixed a handler bug:

Update

/handler-pattern-design/SKILL.md

**Fixed (PR #XX):**
- ~~PassiveComponentHandler duplicate patterns~~ - Removed duplicates

✅ Step 5: Add Cross-References

If you created a NEW significant feature:

1. Add to

   CLAUDE.md

   under appropriate section
2. Add cross-references in related skills
3. Update skill discovery (add to skill list in CLAUDE.md)

Example: New PrefixRegistry feature

Add to

CLAUDE.md

### Component Classification
- `PrefixRegistry` - Cross-manufacturer prefix equivalence mapping

Add to

/equivalent-group-identification/SKILL.md

## See Also
- `PrefixRegistry.java` - Prefix equivalence infrastructure

✅ Step 6: Update HISTORY.md (For Significant Changes)

When to update HISTORY.md:

• Major bug fixes (PR #114-115 OpAmp bug level)
• New features (MPN package suffix support)
• Architecture changes (metadata-driven similarity)
• Handler cleanup batches (PR #73-88)

Format:

### PR #XXX: Brief Title (Date)
**What:** Brief description
**Why:** Problem solved
**Impact:** Who/what is affected
**Files:** Key files changed

Quick Decision Tree

┌─ Did I change code? ───────────────────────────────────┐
│                                                         │
│  ┌─ Is it a bug fix?                                   │
│  │  └─ YES → Add to relevant skill "Learnings & Quirks"│
│  │                                                      │
│  ┌─ Is it a new feature?                               │
│  │  └─ YES → Update skill with examples & patterns     │
│  │                                                      │
│  ┌─ Is it a refactoring?                               │
│  │  └─ YES → Update anti-patterns or cleanup checklists│
│  │                                                      │
│  └─ Is it significant?                                 │
│     └─ YES → Update HISTORY.md                         │
│                                                         │
└─────────────────────────────────────────────────────────┘

Documentation Update Examples

Example 1: Bug Fix (Handler Pattern)

What: Fixed NXPHandler to use matchesForCurrentHandler() instead of matches()

Documentation updates:

1. /handler-pattern-design/SKILL.md

   - Add to Learnings:

### Cross-Handler Pattern Matching Bug (PR #89)
- Using `patterns.matches()` caused NXPHandler to match STM32 parts (ST manufacturer)
- Root cause: matches() searches ALL handlers, not just current
- Fix: Always use `patterns.matchesForCurrentHandler()` in handler matches() method

2. CLAUDE.md

   - Update Known Technical Debt:

**Fixed (PR #89):**
- ~~NXPHandler cross-handler matching bug~~ - Uses matchesForCurrentHandler() now

Example 2: New Feature (Equivalent Groups)

What: Added EquivalentPartRegistry centralization

Documentation updates:

1. /equivalent-group-identification/SKILL.md

   - Add section:

## EquivalentPartRegistry Implementation

**Status:** ✅ Implemented in PR #XXX

**API:**
```java
EquivalentPartRegistry.getInstance().registerGroup(ComponentType.TRANSISTOR, Set.of("2N2222", "PN2222"));

2. **`CLAUDE.md`** - Add to Architecture section:
```markdown
### Equivalent Part Matching
- `EquivalentPartRegistry` - Centralized registry for cross-manufacturer equivalent groups

3. HISTORY.md

   - Add entry:

### PR #XXX: Centralized Equivalent Part Registry (2026-01-24)
**What:** Created EquivalentPartRegistry to centralize hardcoded equivalent groups
**Why:** Eliminate duplication across 4 similarity calculators
**Impact:** Easier to add new equivalent groups, single source of truth
**Files:** EquivalentPartRegistry.java, TransistorSimilarityCalculator.java, etc.

Example 3: Gotcha Discovery (Unicode Issue)

What: Discovered µ→Μ uppercasing breaks capacitor parsing

Documentation updates:

1. /mpn-normalization/SKILL.md

   - Add to Unicode Gotcha section:

### Real-World Bug Example (PR #XXX)

**Bug:** CapacitorSimilarityCalculator failed to parse "10µF"
**Root Cause:** toUpperCase() converts µ (U+00B5) → Μ (U+039C) Greek MU
**Fix:** Replace µ with 'u' BEFORE calling toUpperCase()

```java
// ✅ CORRECT
String normalized = value.replace("µ", "u").replace("Μ", "u");
normalized = normalizeValue(normalized);

---

## Wiring This Into Workflow

### Option 1: Add to /commit Skill (RECOMMENDED)

Update `.claude/skills/commit/SKILL.md` to include:

```markdown
## BEFORE Creating Commit

**🚨 MANDATORY: Run documentation maintenance checklist first!**

```bash
/documentation-maintenance

Ask yourself:

1. Did I update relevant skill files with learnings?
2. Did I add examples for new patterns?
3. Did I update CLAUDE.md for cross-cutting changes?
4. Did I update HISTORY.md for significant features?

---

### Option 2: User Prompt Submit Hook

Add to `.claude/settings.json`:

```json
{
  "hooks": {
    "user-prompt-submit": {
      "command": "echo '⚠️ REMINDER: Update documentation before creating PR! Run: /documentation-maintenance'",
      "when": "commit|PR|pull request"
    }
  }
}

Option 3: Git Pre-Commit Hook

Create

.git/hooks/pre-commit

#!/bin/bash

# Check if documentation was updated in this commit
if git diff --cached --name-only | grep -q "CLAUDE.md\|\.claude/skills"; then
  echo "✅ Documentation updated"
else
  echo "⚠️  WARNING: No documentation updates found!"
  echo "    Consider updating:"
  echo "    - CLAUDE.md (cross-cutting learnings)"
  echo "    - Relevant skill files (.claude/skills/)"
  echo ""
  read -p "Continue anyway? (y/n) " -n 1 -r
  echo
  if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    exit 1
  fi
fi

Common Documentation Anti-Patterns

❌ Don't Do This

1. Skipping documentation "because it's obvious"

// Added fix for handler bug
// (No documentation update)

→ Future developers won't know the bug existed or why the fix is needed

2. Adding TODO comments instead of documenting

// TODO: Document this pattern

→ TODOs rarely get addressed. Document NOW while knowledge is fresh.

3. Documenting in code comments only

// IMPORTANT: Must use matchesForCurrentHandler() not matches()

→ Code comments aren't searchable in skills. Add to skill file too.

4. Updating only CLAUDE.md for specific changes

# CLAUDE.md
- Fixed handler bug (specific to NXPHandler)

→ Should also update

/handler-pattern-design

5. Not updating cross-references

Added new skill but didn't update CLAUDE.md skill list

→ New skill is invisible to users

✅ Do This Instead

1. Document immediately after fixing

• Fix bug → Immediately update skill file
• Add pattern → Add example to skill
• Discover quirk → Add to Learnings section

2. Document in multiple places

• Specific pattern → Skill file
• Cross-cutting → CLAUDE.md
• Significant change → HISTORY.md
• Code comment → For implementation details only

3. Make documentation searchable

• Use keywords (bug, pattern, anti-pattern, gotcha)
• Add to tables for easy reference
• Include code examples

Automation Opportunities

Future improvements:

1. PR template with documentation checklist

## Documentation Updates
- [ ] Updated relevant skill files
- [ ] Added learnings to CLAUDE.md (if cross-cutting)
- [ ] Updated HISTORY.md (if significant)
- [ ] Verified cross-references

2. CI check for documentation updates

# Fail if code changed but no .md files updated
if [[ $CODE_CHANGES -eq 1 && $DOC_CHANGES -eq 0 ]]; then
  echo "ERROR: Code changed but no documentation updated"
  exit 1
fi

3. Automated skill suggestion

# Changed HandlerTest.java → Suggest updating /handler-pattern-design
git diff --name-only | grep Handler → echo "Consider updating /handler-pattern-design"

Checklist Template (Copy-Paste for Each PR)

## Documentation Maintenance Checklist

### Files Changed
- [ ] Handler code → Check `/handler-pattern-design`
- [ ] MPN normalization → Check `/mpn-normalization`
- [ ] Similarity calculator → Check `/similarity-calculator-architecture`
- [ ] Component types → Check `/component-type-detection-hierarchy`
- [ ] Spec extraction → Check `/component-spec-extraction`
- [ ] Metadata conversion → Check `/metadata-driven-similarity-conversion`
- [ ] Manufacturer detection → Check `/manufacturer-detection-from-mpn`
- [ ] Equivalent groups → Check `/equivalent-group-identification`

### Learnings Added
- [ ] Added quirks/gotchas to relevant skill file
- [ ] Added examples of new patterns
- [ ] Updated anti-pattern tables if applicable
- [ ] Added cross-references between related skills

### Cross-Cutting Updates
- [ ] Updated CLAUDE.md if cross-cutting change
- [ ] Updated HISTORY.md if significant feature
- [ ] Updated skill lists in CLAUDE.md if new skill
- [ ] Verified all cross-references resolve

### Verification
- [ ] Read through updated documentation
- [ ] Confirmed examples are accurate
- [ ] Checked markdown formatting
- [ ] Tested cross-reference links

Quick Reference: File → Skill Mapping

*Handler.java

/handler-pattern-design

*HandlerTest.java

/handler-pattern-design

MPNUtils.java

/mpn-normalization

*SimilarityCalculator.java

/similarity-calculator-architecture

ComponentType.java

/component-type-detection-hierarchy

*Spec.java

SpecValue.java

/component-spec-extraction

/metadata-driven-similarity-conversion

ComponentManufacturer.java

/manufacturer-detection-from-mpn

/equivalent-group-identification

CLAUDE.md

HISTORY.md

Learnings & Quirks

Documentation Maintenance Patterns

• Update documentation BEFORE commit: Knowledge is freshest immediately after implementation
• Use copy-paste checklist: Reduces mental load, ensures consistency
• Search before adding: Avoid duplicating existing documentation
• Link between related concepts: Cross-references improve discoverability

Common Mistakes

• Assuming "obvious" changes don't need documentation
• Documenting in code comments instead of skill files
• Forgetting to update cross-references
• Skipping HISTORY.md for significant changes

See Also

• CLAUDE.md - Main project documentation, skill listing
• HISTORY.md - Chronological project history

• /architecture

  - Refactoring and cleanup guidance
• All 8 advanced component skills - Specific domain documentation