Using OpenClaw to Generate API Documentation

API documentation is one of those things every team agrees is important and almost every team lets fall out of date. The problem is not a lack of good intentions — it is that maintaining accurate documentation alongside a rapidly evolving codebase requires constant effort. Every new endpoint, every changed parameter, every deprecated field needs to be reflected in the docs, and manual updates inevitably fall behind.

OpenClaw skills solve this by teaching your AI agent to generate, validate, and maintain API documentation directly from your source code. This guide covers the full workflow, from generating OpenAPI specs to producing human-readable endpoint docs and keeping everything in sync as your API evolves.

The Documentation Problem

Most API documentation fails in one of three ways:

• It does not exist — the team never had time to write it in the first place
• It is incomplete — some endpoints are documented but many are missing or have outdated parameter descriptions
• It is wrong — the docs say one thing but the API does another, usually because someone changed the code without updating the docs

All three of these failures erode trust with API consumers, whether they are external developers, internal frontend teams, or your future self trying to remember what that endpoint does.

Automating documentation generation eliminates the most common failure mode: human forgetfulness. When your docs are generated from the code itself, they stay accurate by definition.

Generating OpenAPI Specs

The openapi-generator skill teaches your agent to analyze your API routes, controllers, and models to produce a complete OpenAPI 3.1 specification.

openclaw skill install openapi-generator

Once installed, point the agent at your API codebase:

openclaw generate openapi --source src/api --output docs/openapi.yaml

The agent scans your route definitions, request handlers, middleware, and data models to produce a spec that includes:

• Paths and operations — every endpoint with its HTTP method, path, and operation ID
• Request bodies — inferred from validation schemas, TypeScript types, or runtime parsing logic
• Response schemas — derived from return types, serializers, or response builder patterns
• Authentication requirements — detected from auth middleware attached to routes
• Error responses — common error shapes extracted from error handling middleware

Example: Express.js API

Given an Express route like this:

router.post(
  "/users",
  authenticate,
  validate(createUserSchema),
  async (req, res) => {
    const user = await userService.create(req.body);
    res.status(201).json(user);
  }
);

The agent produces this OpenAPI path:

/users:
  post:
    operationId: createUser
    security:
      - bearerAuth: []
    requestBody:
      required: true
      content:
        application/json:
          schema:
            $ref: "#/components/schemas/CreateUserRequest"
    responses:
      "201":
        description: User created successfully
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/User"
      "400":
        description: Validation error
      "401":
        description: Unauthorized

The skill handles Express, Fastify, Hono, Koa, Flask, Django REST Framework, FastAPI, Go Chi, Gin, and Spring Boot out of the box. You can extend it to support other frameworks by adding route detection patterns to the skill configuration.

Generating Endpoint Documentation

A raw OpenAPI spec is useful for tooling, but developers need readable documentation. The api-docs-writer skill generates clear, practical endpoint documentation from your spec or directly from your source code.

openclaw skill install api-docs-writer

This skill produces documentation that includes:

• Endpoint summaries — a one-line description of what each endpoint does
• Parameter tables — every path param, query param, header, and body field with its type, required status, and description
• Request examples — realistic curl commands and code snippets for common languages
• Response examples — sample JSON responses for success and error cases
• Authentication notes — which auth method is required and how to provide credentials
• Rate limiting — any rate limits that apply to the endpoint

Example Output

## POST /users

Create a new user account.

**Authentication:** Bearer token required

### Request Body

| Field    | Type   | Required | Description           |
|----------|--------|----------|-----------------------|
| email    | string | yes      | User's email address  |
| name     | string | yes      | Full name             |
| role     | string | no       | Default: "member"     |

### Example Request

curl -X POST https://api.example.com/users \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"email": "jane@example.com", "name": "Jane Smith"}'

### Response (201)

{
  "id": "usr_abc123",
  "email": "jane@example.com",
  "name": "Jane Smith",
  "role": "member",
  "createdAt": "2026-03-29T10:00:00Z"
}

Generating SDK Documentation

If you publish client SDKs for your API, the sdk-docs-generator skill produces language-specific documentation that matches your SDK's actual interface.

openclaw skill install sdk-docs-generator

The agent reads your SDK source code — the function signatures, parameter types, return types, and JSDoc/docstring comments — and generates documentation that SDK consumers can follow directly.

For a TypeScript SDK, the output includes:

• Method signatures with full type annotations
• Parameter descriptions extracted from JSDoc or inferred from names and types
• Usage examples that show real-world patterns, not just trivial calls
• Error handling guidance for each method

openclaw generate sdk-docs --source sdk/src --language typescript --output docs/sdk/

The skill supports TypeScript, Python, Go, Java, Ruby, and PHP SDKs. Each language's output follows the documentation conventions native to that ecosystem — JSDoc-style for TypeScript, docstring-style for Python, godoc-style for Go, and so on.

Keeping Docs in Sync

Generating docs once is easy. Keeping them accurate over time is the hard part. The docs-sync skill solves this by detecting when your API code changes and flagging documentation that needs to be updated.

openclaw skill install docs-sync

CI Integration

Add a docs sync check to your CI pipeline so that every PR that changes API code also updates the documentation:

# .github/workflows/docs-sync.yml
name: Documentation Sync Check
on:
  pull_request:
    paths:
      - "src/api/**"
      - "docs/api/**"

jobs:
  check-docs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Check Documentation Sync
        run: |
          openclaw docs sync-check \
            --api-source src/api \
            --docs-path docs/api \
            --openapi-spec docs/openapi.yaml
        env:
          OPENCLAW_API_KEY: ${{ secrets.OPENCLAW_API_KEY }}

When the check runs, the agent compares the current API code against the existing documentation and reports:

• New endpoints that are not documented
• Changed parameters that have outdated documentation
• Removed endpoints that still appear in the docs
• Schema mismatches where the documented response shape does not match the actual return type

If any drift is detected, the CI check fails with a clear report of what needs to be updated. The agent can also auto-fix the documentation by running:

openclaw docs sync --api-source src/api --docs-path docs/api --fix

Building the Complete Documentation Pipeline

Here is a recommended setup that covers the full documentation lifecycle:

1. Install the skill stack:

openclaw skill install openapi-generator
openclaw skill install api-docs-writer
openclaw skill install sdk-docs-generator
openclaw skill install docs-sync

2. Generate initial documentation from your existing codebase:

openclaw generate openapi --source src/api --output docs/openapi.yaml
openclaw generate api-docs --source src/api --output docs/api/
openclaw generate sdk-docs --source sdk/src --language typescript --output docs/sdk/

3. Add CI checks to keep documentation in sync with every PR.

4. Set up auto-regeneration on merge to main so the published docs always reflect the latest code.

This workflow ensures that your API documentation is always accurate, complete, and up to date — without requiring any manual effort from your team.

Explore the skills directory to find documentation skills tailored to your framework and language.

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