openapi-spec-generation

★ 37,559

by wshobson · part of wshobson/agents

Generate and maintain OpenAPI 3.1 specifications from code, design-first specs, and validation patterns. Use when creating API documentation, generating SDKs, or ensuring API contract compliance.

🧩 One of 7 skills in the wshobson/agents package — works on its own, and pairs well with its siblings.

This is the playbook your agent receives when the skill activates — you don't need to read it to use the skill, but it's here to audit before installing.

OpenAPI Spec Generation

Comprehensive patterns for creating, maintaining, and validating OpenAPI 3.1 specifications for RESTful APIs.

When to Use This Skill

Creating API documentation from scratch
Generating OpenAPI specs from existing code
Designing API contracts (design-first approach)
Validating API implementations against specs
Generating client SDKs from specs
Setting up API documentation portals

Core Concepts

1. OpenAPI 3.1 Structure

openapi: 3.1.0
info:
  title: API Title
  version: 1.0.0
servers:
  - url: https://api.example.com/v1
paths:
  /resources:
    get: ...
components:
  schemas: ...
  securitySchemes: ...

2. Design Approaches

Approach	Description	Best For
Design-First	Write spec before code	New APIs, contracts
Code-First	Generate spec from code	Existing APIs
Hybrid	Annotate code, generate spec	Evolving APIs

Templates and detailed worked examples

Full template library and detailed worked examples live in references/details.md. Read that file when you need the concrete templates.

Best Practices

Do's

Use $ref - Reuse schemas, parameters, responses
Add examples - Real-world values help consumers
Document errors - All possible error codes
Version your API - In URL or header
Use semantic versioning - For spec changes

Don'ts

Don't use generic descriptions - Be specific
Don't skip security - Define all schemes
Don't forget nullable - Be explicit about null
Don't mix styles - Consistent naming throughout
Don't hardcode URLs - Use server variables