Documentation Maintenance Skill

When to use this skill

✅ ALWAYS Trigger

• Post-Feature: After completing any user story or AC
• Pre-Commit: Before git push if files changed in /src, /app, /lib, /db
• Architecture Change: DB schema, API contracts, auth logic modified
• New Route/Page: Any file added to /app directory
• Design Token Change: Modifications to colors, spacing, typography in code
• Explicit Request: User says "update docs", "sync documentation", "cleanup docs"

❌ NEVER Trigger

• Trivial changes (<10 lines, no business logic)
• Fixing typos in code comments
• Refactoring without behavior change
• Package updates in package.json (unless major version or new package)
• Test file additions (unless testing new features)

⚠️ ASK FIRST

• Experimental features (ask: "Should I document this now or wait until stable?")
• Breaking changes (ask: "Should I document the migration path?")
• Hotfixes (ask: "Update docs now or after proper solution?")

---

Canonical Structure

/
├── CLAUDE.md                      # ⭐ AI reads FIRST every session
└── docs/
    ├── progress.txt               # Session memory bridge
    ├── product/
    │   ├── prd.md                 # Feature requirements + status
    │   ├── app-flow.md            # Navigation + user flows
    │   ├── product-overview.md    # Vision + goals
    │   ├── product-roadmap.md     # Planned features
    │   ├── sections/
    │   │   └── [section-id]/
    │   │       └── spec.md        # Detailed US + AC
    │   ├── shell/
    │   │   ├── spec.md            # Layout/nav spec
    │   │   └── components/        # Shell components
    │   └── types.ts               # Shared types
    ├── design-system/
    │   ├── guidelines.md          # Design rules (prose)
    │   ├── design-system.json     # Tokens (structured)
    │   ├── components.md          # Component library
    │   └── design-rules.md        # Optional constraints
    └── system/
        ├── tech-stack.md          # Dependencies (exact versions)
        ├── data-flow.md           # Data sources + viz logic
        ├── data-consistency.md    # ⭐ GOLDEN formulas
        ├── implementation-plan.md # Build sequence
        └── backend-structure/
            ├── backend-structure.md
            ├── database-model.md       # Schema + relations
            ├── architecture-overview.md
            ├── api-expectations.md     # Endpoint contracts
            ├── module-map.md           # Code organization
            └── auth-model.md           # Auth flows

---

Decision Tree: What to Update

Use this deterministic tree to decide which docs need updates:

START
│
├─ Changed /app routes or pages?
│  ├─ YES → Update app-flow.md + progress.txt
│  │       └─ New feature? → Create sections/[id]/spec.md
│  └─ NO → Continue
│
├─ Changed DB schema or API?
│  ├─ YES → Update backend-structure/database-model.md
│  │       └─ API contracts changed? → Update api-expectations.md
│  │       └─ New dependencies? → Update tech-stack.md
│  └─ NO → Continue
│
├─ Changed business logic or calculations?
│  ├─ YES → Update data-consistency.md (GOLDEN SOURCE)
│  │       └─ grep all docs for old formula → Replace with LINK
│  └─ NO → Continue
│
├─ Changed UI components or design tokens?
│  ├─ YES → Update design-system.json tokens
│  │       └─ New component? → Update components.md
│  │       └─ Design rule changed? → Update guidelines.md
│  └─ NO → Continue
│
├─ Feature status changed?
│  ├─ YES → Update prd.md status (🚧 → ✅)
│  │       └─ Update progress.txt with [x]
│  └─ NO → Continue
│
└─ DONE

---

Update Workflow

Step 1: Session Start

# ALWAYS do this first
1. Read CLAUDE.md to load project context
2. Read progress.txt to understand current state
3. Ask: "What changed since last session?"

Step 2: Determine Scope (use Decision Tree above)

Step 3: Execute Updates

For each file to update:

1. Check redundancy: Does this info exist elsewhere?

   • If YES → Add link, don't duplicate
   • If NO → Proceed

2. Update the file:

   • Find exact section to modify
   • Make minimal, surgical change
   • Preserve existing structure

3. Update cross-references:

   • If file moved/renamed → grep -r "old-name" docs/
   • Fix all broken links

4. Update progress.txt:

   • Mark items [x] done
   • Add new items [ ] if needed

Step 4: Validate

# Run these checks
1. grep -r "\[.*\](.*.md)" docs/  # Find all internal links
2. Check each link exists
3. Verify no duplicate content (same formula in 2 places)
4. Confirm progress.txt reflects reality

---

Golden Rules

Single Source of Truth

Topic	Owner Document
Calculations/formulas	data-consistency.md
DB schema	backend-structure/database-model.md
API contracts	backend-structure/api-expectations.md
Dependencies	tech-stack.md
Design tokens	design-system.json
User flows	app-flow.md

Rule: If info exists in owner doc → Link to it. Never copy.

File Placement

• ❌ Never put loose .md files in /docs/ root
• ✅ Always organize under product/, system/, or design-system/
• ✅ Exception: Only CLAUDE.md (root), progress.txt (docs/)

CLAUDE.md Priority

• CLAUDE.md is AI's operating manual
• Update it when conventions change
• Keep it under 2000 words (AI loads it every session)

Progress.txt Discipline

• Update EVERY feature completion
• Format: [x] Feature name - Brief status
• Acts as session memory bridge

---

Common Scenarios

Scenario 1: "Feature X is complete"

Trigger: Post-feature
Files to check:
1. progress.txt → Mark [x]
2. prd.md → Update status to ✅
3. sections/X/spec.md → Verify spec matches implementation
4. app-flow.md → If new routes added
5. data-consistency.md → If formulas involved

Scenario 2: "Changed DB schema"

Trigger: Architecture change
Files to update:
1. backend-structure/database-model.md → Document new schema
2. backend-structure/api-expectations.md → If endpoints changed
3. tech-stack.md → If new DB packages added
4. progress.txt → Record change

Scenario 3: "Added /dashboard/analytics page"

Trigger: New route
Files to update:
1. app-flow.md → Add route + user flow description
2. progress.txt → Add to completed
3. sections/analytics/spec.md → Create if new feature domain
4. prd.md → If this fulfills a requirement

Scenario 4: "Changed button radius from 16px to 12px"

Trigger: Design token change
Files to update:
1. design-system.json → Update radius-button token
2. design-system/guidelines.md → Update if explanation needed
3. DO NOT update individual component files (they reference tokens)

Scenario 5: "Formula for inventory calculation changed"

Trigger: Business logic change
Files to update:
1. data-consistency.md → Update THE formula (golden source)
2. Run: grep -r "old formula pattern" docs/
3. Replace all occurrences with LINK to data-consistency.md
4. sections/inventory/spec.md → Link to data-consistency.md

Scenario 6: "Cleanup documentation"

Trigger: Explicit request
Actions:
1. find docs/ -name "*.md" -type f
2. Check each file against canonical structure
3. Move misplaced files to correct folders
4. rm temp_*.md old_*.md backup_*.md
5. Run link audit: grep -r "\[.*\](.*.md)" docs/
6. Fix broken links
7. Report summary of changes

Scenario 7: "Starting new session"

Trigger: Session start
Actions:
1. Read CLAUDE.md first (AI context)
2. Read progress.txt (what's done/in-progress)
3. Ask user: "What are we working on today?"
4. Proceed with work

---

Pre-Commit Checklist

Before git push, verify:

[ ] progress.txt updated?
[ ] Feature status in prd.md reflects reality?
[ ] Relevant spec files synced with implementation?
[ ] New pages documented in app-flow.md?
[ ] Design changes in design-system/?
[ ] Backend changes in backend-structure/?
[ ] No broken internal links? (grep check)
[ ] No duplicate content? (same info in 2+ places)
[ ] CLAUDE.md updated if conventions changed?

---

Validation Commands

Run these to verify docs health:

# Find all internal markdown links
grep -r "\[.*\](.*.md)" docs/

# Find potential duplicates (same heading in multiple files)
grep -r "^## " docs/ | sort | uniq -d

# Find files not in canonical structure
find docs/ -maxdepth 1 -name "*.md" ! -name "progress.txt"

# Check for TODO/FIXME in docs
grep -r "TODO\|FIXME" docs/

---

Error Prevention

Common Mistakes to Avoid

1. Updating latest instead of best

   • ❌ Always updating the newest file
   • ✅ Check if older version has better info

2. Duplicating instead of linking

   • ❌ Copying formula to multiple docs
   • ✅ Reference data-consistency.md

3. Forgetting progress.txt

   • ❌ Only updating specs
   • ✅ Always update progress.txt too

4. Breaking links when moving files

   • ❌ Moving file without updating references
   • ✅ grep for all references first

5. Over-documenting trivial changes

   • ❌ Updating docs for 2-line fix
   • ✅ Use "When NOT to use" criteria

---

Success Metrics

After using this skill, docs should be:

✅ Consistent - No contradictions between files
✅ Complete - All implemented features documented
✅ Current - Reflects actual codebase state
✅ Linked - Cross-references work, no duplicates
✅ Organized - Files in correct canonical folders
✅ Accessible - CLAUDE.md + progress.txt provide entry points