API Documentation Skill

Technical documentation, API references, user guides, and docs-as-code workflows.

Documentation Project Scaffolding

Recommended Folder Structure

docs-project/
├── .github/
│   ├── copilot-instructions.md    # Docs-specific Alex context
│   └── prompts/
│       └── api-review.prompt.md
├── docs/
│   ├── index.md                   # Landing page / overview
│   ├── getting-started/
│   │   ├── installation.md
│   │   ├── quick-start.md
│   │   └── configuration.md
│   ├── guides/
│   │   ├── user-guide.md
│   │   └── admin-guide.md
│   ├── api/
│   │   ├── overview.md
│   │   ├── authentication.md
│   │   ├── endpoints/
│   │   │   └── [resource].md
│   │   └── errors.md
│   ├── reference/
│   │   ├── glossary.md
│   │   └── faq.md
│   └── contributing/
│       ├── style-guide.md
│       └── templates.md
├── examples/
│   ├── code-snippets/
│   └── sample-projects/
├── assets/
│   ├── images/
│   └── diagrams/
├── CHANGELOG.md
├── README.md
└── mkdocs.yml                     # Or docusaurus.config.js

DOCS-PLAN.md Template

# Documentation Plan: [Product/API Name]

## Scope
- **Product**: [What are we documenting?]
- **Audience**: [Developers / Admins / End Users]
- **Prerequisites**: [What readers should know]

## Documentation Types

| Type | Location | Status |
|------|----------|--------|
| Getting Started | docs/getting-started/ | ⬜ |
| User Guide | docs/guides/user-guide.md | ⬜ |
| API Reference | docs/api/ | ⬜ |
| Examples | examples/ | ⬜ |

## Style Guidelines
- **Tone**: [Technical but approachable]
- **Person**: [Second person - "you"]
- **Tense**: [Present tense]
- **Code style**: [Language-specific conventions]

## Quality Checklist
- [ ] All endpoints documented
- [ ] Code examples tested and working
- [ ] Screenshots current
- [ ] Links verified
- [ ] Spelling/grammar checked

API-ENDPOINT.md Template

# [Endpoint Name]

[One-line description of what this endpoint does]

## Request

\`\`\`http
[METHOD] /api/v1/[resource]
\`\`\`

### Headers

| Header | Required | Description |
|--------|----------|-------------|
| Authorization | Yes | Bearer token |
| Content-Type | Yes | application/json |

### Parameters

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| id | string | Yes | Resource identifier |

### Request Body

\`\`\`json
{
  "field": "value"
}
\`\`\`

## Response

### Success (200 OK)

\`\`\`json
{
  "data": {
    "id": "123",
    "field": "value"
  }
}
\`\`\`

### Errors

| Code | Description |
|------|-------------|
| 400 | Invalid request body |
| 401 | Unauthorized |
| 404 | Resource not found |

## Example

\`\`\`bash
curl -X GET "https://api.example.com/v1/resource/123" \
  -H "Authorization: Bearer $TOKEN"
\`\`\`

copilot-instructions.md Template (Documentation Projects)

# [Product Name] Documentation — Context

## Project Overview
[What product/API this documents, current status]

## Current Phase
- [x] Structure defined
- [ ] Getting started complete
- [ ] API reference complete
- [ ] Examples tested

## Key Files
- Docs plan: DOCS-PLAN.md
- Style guide: docs/contributing/style-guide.md
- API overview: docs/api/overview.md

## Alex Guidance
- **Audience**: [Developers with X experience level]
- **Tone**: Technical but approachable
- Use second person ("you") not third person
- Include working code examples for every endpoint
- Link to related endpoints/concepts

## Style Rules
- Headings: Sentence case
- Lists: No periods for fragments, periods for sentences
- Code: Include language identifier in fenced blocks
- Links: Use relative paths within docs/

## Don't
- Don't assume reader knows internal terminology
- Don't document deprecated features without clear warnings
- Don't include placeholder examples — all code must work

Documentation Project Audit Checklist

## Documentation Project Audit

### Structure Assessment
- [ ] Clear navigation hierarchy
- [ ] Getting started section exists
- [ ] API reference organized by resource
- [ ] Examples directory with working code

### Alex-Readiness Assessment
- [ ] copilot-instructions.md exists
- [ ] Audience clearly defined
- [ ] Style guide documented
- [ ] Key files linked

### Content Assessment
- [ ] All public endpoints documented
- [ ] Authentication explained
- [ ] Error codes listed
- [ ] Code examples in multiple languages (if applicable)

### Quality Assessment
- [ ] All links valid
- [ ] Code examples tested
- [ ] Screenshots current
- [ ] Consistent formatting

Documentation Types

API Reference Structure

Section	Purpose
Overview	What the API does, base URL, versioning
Authentication	How to get and use credentials
Rate Limits	Throttling rules and headers
Endpoints	Per-endpoint details
Errors	Error format and common codes
Changelog	API version history

User Guide Structure

Section	Purpose
Introduction	What, why, for whom
Installation	How to set up
Quick Start	First success in 5 minutes
Core Concepts	Key ideas to understand
How-To Guides	Task-oriented walkthroughs
Troubleshooting	Common issues and fixes

README Best Practices

Section	Required?
Project name + description	✅ Yes
Badges (build, version)	Recommended
Quick start / Installation	✅ Yes
Usage examples	✅ Yes
Configuration	If applicable
Contributing	Recommended
License	✅ Yes

Docs-as-Code Tools

Static Site Generators

Tool	Best For	Config File
MkDocs	Python projects, simple setup	mkdocs.yml
Docusaurus	React, versioning, i18n	docusaurus.config.js
Sphinx	Python autodocs	conf.py
GitBook	Beautiful docs, non-technical	book.json
VitePress	Vue projects, fast	.vitepress/config.js

API Documentation Tools

Tool	Format	Output
OpenAPI/Swagger	YAML/JSON spec	Interactive docs
Redoc	OpenAPI	Static HTML
Stoplight	Design-first	Portal
Postman	Collections	Shareable docs

Writing Patterns

The 4 Cs of Technical Writing

Principle	Meaning
Clear	No ambiguity, simple words
Concise	No filler, respect reader's time
Correct	Accurate, tested, up-to-date
Complete	All needed info present

Code Example Guidelines

Do	Don't
Show complete, runnable examples	Partial snippets without context
Include error handling	Happy path only
Use realistic data	`foo`, `bar`, `test123`
Explain non-obvious parts	Assume reader knows everything

Common Pitfalls

Pitfall	Solution
Outdated screenshots	Automate with Puppeteer/Playwright
Broken links	CI link checking
Stale examples	Tests for code samples
Jargon overload	Glossary + define on first use

Synapses

High-Strength Connections

[project-scaffolding] (High, Extends, Bidirectional) — "Documentation project structure"
[code-quality] (High, Complements, Bidirectional) — "Documented code is quality code"

Medium-Strength Connections

[creative-writing] (Medium, Complements, Forward) — "Clear writing techniques"
[git-workflow] (Medium, Uses, Forward) — "Docs-as-code versioning"

Supporting Connections

[markdown-mastery] (Medium, Uses, Forward) — "Core formatting"
[appropriate-reliance] (Low, Applies, Forward) — "AI assistance in docs"