Technical Documentation — Quick Reference

This skill provides execution-ready patterns for writing clear, maintainable technical documentation. Claude should apply these patterns when users need README files, API docs, ADRs, changelogs, or any technical writing.

Modern Best Practices (2025): Docs-as-code workflows, Markdown standardization, automated changelog generation, ADRs, interactive API docs (OpenAPI 3.2+), documentation testing, accessibility standards (WCAG 2.2), and docs in version control with CI/CD.

When to Use This Skill

Claude should invoke this skill when a user requests:

• Writing README files for projects
• Documenting APIs (REST, GraphQL, gRPC)
• Creating architecture decision records (ADRs)
• Writing changelogs and release notes
• Creating contributing guidelines
• Documenting code with comments and docstrings
• Setting up docs-as-code workflows
• Creating user guides and tutorials
• Writing technical specifications
• Building documentation sites (MkDocs, Docusaurus)

Quick Reference

Decision Tree: Choosing Documentation Type

User needs: [Documentation Task]
    ├─ New project or repository?
    │   └─ **README.md** (project overview, installation, quick start)
    │
    ├─ Made important technical decision?
    │   ├─ Architecture or design choice? → **ADR** (adr-template.md)
    │   └─ Technology choice? → **ADR** with alternatives section
    │
    ├─ Building or documenting API?
    │   ├─ REST API? → **OpenAPI 3.1** spec + api-docs-template
    │   ├─ GraphQL API? → Schema-first + GraphQL Docs
    │   └─ gRPC API? → Protobuf + generated docs
    │
    ├─ Releasing new version?
    │   ├─ Manual changelog? → **CHANGELOG.md** (Keep a Changelog format)
    │   └─ Automated? → semantic-release + Conventional Commits
    │
    ├─ Open source or team collaboration?
    │   ├─ Contribution workflow? → **CONTRIBUTING.md**
    │   ├─ Code of conduct? → CODE_OF_CONDUCT.md
    │   └─ License? → LICENSE file
    │
    ├─ Documenting code?
    │   ├─ Public API/library? → **Docstrings** (JSDoc, Python, etc.)
    │   ├─ Complex logic? → **Comments** (explain WHY, not WHAT)
    │   └─ Architecture? → **README** in module/package + diagrams
    │
    ├─ Building documentation site?
    │   ├─ Python project? → **MkDocs** + Material theme
    │   ├─ JavaScript/React? → **Docusaurus** (versioning support)
    │   └─ Next.js? → **Nextra** (minimal setup)
    │
    └─ Troubleshooting guide?
        └─ Common issues → Solutions → Diagnostic commands → Logs location

Navigation: README Documentation

README Best Practices -

resources/readme-best-practices.md

Comprehensive guide for creating effective README files with:

• Essential 13-section structure (Name, Features, Prerequisites, Installation, Configuration, Usage, etc.)
• Copy-paste ready installation commands
• Configuration table templates
• Troubleshooting patterns
• Badge recommendations
• Anti-patterns to avoid
• README quality checklist

When to use: Creating new project README or improving existing documentation.

Navigation: Architecture Documentation

ADR Writing Guide -

resources/adr-writing-guide.md

Complete guide for documenting architectural decisions with:

• 8-section ADR structure (Title, Status, Context, Decision, Consequences, Alternatives, Implementation, References)
• Status lifecycle (Proposed → Accepted → Deprecated → Superseded)
• How to document trade-offs and alternatives
• ADR naming conventions and indexing
• When to write vs skip ADRs
• Real-world examples with metrics

When to use: Documenting technical decisions like database choice, framework selection, or architecture patterns.

Template: templates/architecture/adr-template.md

Navigation: Changelog Documentation

Changelog Best Practices -

resources/changelog-best-practices.md

Guide for maintaining changelogs using Keep a Changelog format with:

• 6 change categories (Added, Changed, Deprecated, Removed, Fixed, Security)
• Semantic versioning rules (MAJOR.MINOR.PATCH)
• Unreleased section management
• Conventional Commits integration
• Automated changelog generation (semantic-release, standard-version)
• Breaking change communication
• Linking to Git commits

When to use: Creating release notes, maintaining version history, documenting breaking changes.

Template: templates/project-management/changelog-template.md

Navigation: API Documentation

API Documentation Standards -

resources/api-documentation-standards.md

Modern API documentation standards covering:

• REST API documentation (OpenAPI 3.1/3.2, authentication, endpoints, errors)
• GraphQL API documentation (schema, queries, mutations)
• gRPC API documentation (Protocol Buffers, service definitions)
• Essential elements (base URL, auth, rate limiting, pagination, webhooks)
• Error response format (RFC 7807)
• Interactive documentation tools (Swagger UI, Redoc, Stoplight)
• Code examples in multiple languages

When to use: Documenting REST, GraphQL, or gRPC APIs for developers.

Template: templates/api-reference/api-docs-template.md

Navigation: Code Comments & Docstrings

Code Commenting Guide -

resources/code-commenting-guide.md

Comprehensive guide for effective code documentation with:

• Core principles (Comment WHY not WHAT, avoid obvious comments, keep updated)
• Docstring formats (JSDoc, Python Google Style, TSDoc, Godoc)
• Inline comment best practices
• When to use documentation vs implementation comments
• Comment anti-patterns (commented-out code, redundant comments, changelog comments)
• TODO/FIXME/HACK comment standards
• Accessibility comments (ARIA labels)

When to use: Documenting code for maintainability, writing public API documentation.

Navigation: Contributing Guidelines

Contributing Guide Standards -

resources/contributing-guide-standards.md

Guide for creating CONTRIBUTING.md files with:

• 9-section structure (Welcome, Ways to Contribute, Setup, Workflow, Code Style, Review, Issues, Community, Recognition)
• Development setup instructions
• Conventional Commits format
• Pull request workflow
• Code style guidelines (JavaScript, Python, testing)
• Code review expectations
• Bug reporting and feature request templates
• Security vulnerability reporting

When to use: Setting up contribution process for open-source or team projects.

Template: templates/project-management/contributing-template.md

Navigation: Docs-as-Code Workflows

Docs-as-Code Setup -

resources/docs-as-code-setup.md

Setting up documentation with version control and CI/CD:

• MkDocs configuration and Material theme
• Docusaurus setup for versioned docs
• GitBook integration
• GitHub Actions for automated deployment
• Documentation site structure
• Search and navigation patterns

When to use: Building documentation sites with automated deployment.

Navigation: Writing & Testing

Technical Writing Best Practices -

resources/writing-best-practices.md

Clear communication principles:

• Active voice and conciseness
• Plain language guidelines
• Audience awareness
• Structure and formatting
• Writing style consistency

Markdown Style Guide -

resources/markdown-style-guide.md

Markdown formatting standards:

• Syntax reference (headers, lists, code blocks, tables)
• Style consistency rules
• Link formatting
• Code block language tags
• Table formatting

Documentation Testing -

resources/documentation-testing.md

Automated documentation quality checks:

• Linting with markdownlint and Vale
• Link validation with markdown-link-check
• Spell checking with cspell
• Code example testing
• CI/CD integration

When to use: Establishing documentation standards, automating quality checks.

Templates

Complete copy-paste ready templates organized by domain:

Architecture Documentation

• ADR Template: templates/architecture/adr-template.md - Architecture Decision Records for technical decisions

API Reference

• API Docs Template: templates/api-reference/api-docs-template.md - REST/GraphQL API documentation with authentication, endpoints, webhooks

Project Management

• README Template: templates/project-management/readme-template.md - Project overview, installation, usage
• Changelog Template: templates/project-management/changelog-template.md - Keep a Changelog format with semantic versioning
• Contributing Guide: templates/project-management/contributing-template.md - Contribution workflow, code standards, commit guidelines

Docs-as-Code

• Docs Structure Template: templates/docs-as-code/docs-structure-template.md - IA, folder structure, freshness metadata
• Docs Ownership Model: templates/docs-as-code/ownership-model.md - Owners, review cadence, enforcement

Do / Avoid (Dec 2025)

Do

• Assign owners and review cadences to docs that matter (runbooks, onboarding, APIs).
• Add CI checks for links, style, and stale docs where feasible.
• Prefer small, task-oriented docs over “big wiki pages”.

Avoid

• Docs without owners (guaranteed to rot).
• Stale runbooks (dangerous during incidents).
• Copy/paste docs that drift from code and config.

What Good Looks Like

• Ownership: every critical doc has an owner and review cadence (runbooks, onboarding, APIs).
• Structure: consistent information architecture (tutorial/how-to/reference/explanation) and clear navigation.
• Quality gates: CI runs link checks and linting; stale docs are flagged.
• Decision capture: ADRs exist for major choices and are referenced from code and runbooks.
• Onboarding: a new engineer can get to a first PR within a defined target time (tracked and improved).

Optional: AI / Automation

Use only when explicitly requested and policy-compliant.

• Draft and summarize docs changes; humans review before publishing.
• Generate doc diffs in PRs; do not auto-merge.

External Resources

See data/sources.json for:

• Style Guides: Google Developer Docs, Microsoft Writing Guide, Write the Docs
• Documentation Tools: MkDocs, Docusaurus, GitBook, Nextra, Mintlify
• API Documentation: OpenAPI, Swagger UI, Redoc, GraphQL Docs
• Testing Tools: Vale (prose linting), markdownlint, cspell (spell check), markdown-link-check
• Patterns: Keep a Changelog, Semantic Versioning, ADRs, Conventional Commits
• Learning: Google Technical Writing Courses, Docs for Developers (book)

Related Skills

• Documentation Audit: ../qa-docs-coverage/SKILL.md - Audit codebases for documentation gaps, generate coverage reports, identify what needs documenting
• API Design: ../dev-api-design/SKILL.md - REST API patterns, endpoint design, versioning strategies
• Code Review: ../software-code-review/SKILL.md - Code review checklists including documentation standards
• Testing: ../qa-testing-strategy/SKILL.md - Test documentation patterns, test plan templates
• Git Workflow: ../git-workflow/SKILL.md - Commit message standards (Conventional Commits), changelog automation
• PRD Development: ../docs-ai-prd/SKILL.md - PRD templates, tech specs, story mapping for new features

Navigation: Production Gotchas Documentation

Purpose: Document platform-specific issues, silent failures, and hard-to-debug problems to prevent repeated mistakes.

When to Use: After discovering a production issue that:

• Took significant time to debug
• Was caused by external service configuration (not your code)
• Could affect other developers on the team
• Has a non-obvious solution

Gotcha Documentation Structure

## Production Gotchas

### [Provider/Feature Name]

- **The Trap**: What looks correct but actually fails
- **Symptom**: How the issue manifests (error messages, behavior)
- **Root Cause**: Why it happens (the underlying reason)
- **Fix**: Step-by-step solution
- **Prevention**: How to avoid this in the future

Example Gotchas (Real-World)

## Production Gotchas

### Vercel Cron Jobs Require Pro Plan

- **The Trap**: Cron configuration in vercel.json looks valid, jobs never run
- **Symptom**: Scheduled tasks (notifications, data cleanup) never execute; no errors in logs
- **Root Cause**: Vercel Free tier doesn't support cron jobs; requires Pro plan ($20/month)
- **Fix**: Upgrade to Vercel Pro, verify cron jobs in Vercel dashboard under "Cron Jobs" tab
- **Prevention**: Check Vercel plan requirements before implementing scheduled features

### Supabase Site URL Misconfiguration

- **The Trap**: OAuth redirects users to localhost instead of production domain
- **Symptom**: Users click "Sign in with Google" → redirected to localhost:3000 → broken auth
- **Root Cause**: Site URL in Supabase Dashboard → Authentication → URL Configuration still set to localhost
- **Fix**: Set Site URL to `https://your-production-domain.com` (no trailing slash)
- **Prevention**: Add Site URL configuration to deployment checklist

### Apple OAuth Secret Expiration

- **The Trap**: Apple Sign-In stops working after 6 months with no warning
- **Symptom**: "Invalid client secret" error on Apple OAuth flow
- **Root Cause**: Apple's client secret JWT expires in 180 days (not documented clearly)
- **Fix**: Regenerate client secret using .p8 key: `npm run generate-apple-secret`
- **Prevention**: Set calendar reminder 7 days before expiration; consider automation

### Next.js API Route JSON Parsing

- **The Trap**: API returns 500 error when client sends malformed JSON
- **Symptom**: `SyntaxError: Unexpected token` in server logs; client sees generic 500
- **Root Cause**: `await request.json()` throws if body isn't valid JSON
- **Fix**: Wrap in try-catch, return 400 with helpful message
- **Prevention**: Create reusable `parseRequestBody` utility (see software-backend skill)

Where to Document Gotchas

CLAUDE.md

docs/gotchas.md

TROUBLESHOOTING.md

Gotcha Documentation Checklist

[ ] Gotcha has clear, searchable title
[ ] Symptom describes what user sees (error messages, behavior)
[ ] Root cause explains WHY (not just WHAT)
[ ] Fix has step-by-step instructions
[ ] Prevention explains how to avoid in future
[ ] Added to project documentation
[ ] Shared with team (Slack, standup, PR comment)

Anti-Patterns

• Too vague: "Sometimes auth breaks" → Add specific error messages and conditions
• Missing root cause: "Set Site URL to production" → Explain WHY this matters
• No prevention: Fix alone isn't enough → How to avoid this next time?
• Buried in code comments: Gotchas should be discoverable, not hidden in code

Usage Notes

For Claude: When a user requests documentation:

1. Identify documentation type using the Decision Tree
2. Reference appropriate template from templates/ directory
3. Follow best practices from relevant resource file
4. Provide copy-paste ready content with user's specific context
5. Include examples from templates or resources
6. Mention related skills if user might need complementary guidance

Common workflows:

• New project: README template → Contributing guide → Changelog
• API development: API docs template → OpenAPI spec → Interactive docs
• Technical decision: ADR template → Document alternatives → Reference in README
• Open source setup: README → CONTRIBUTING.md → CODE_OF_CONDUCT.md → LICENSE

Quality checks:

• Verify all links work (use markdown-link-check)
• Run spell checker (cspell)
• Lint Markdown (markdownlint)
• Test code examples actually run
• Check accessibility (WCAG 2.2 for web docs)

Success Criteria: Documentation is clear, accurate, up-to-date, discoverable, and enables users to be productive quickly with minimal support.