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Skills wshobson agents

api-design-principles

Use it when:
You're designing a new REST or GraphQL API, reviewing an API spec, or setting API standards for a team.
It does:
Gives the agent principles for resources, HTTP methods, GraphQL schemas, versioning, pagination, rate limits and errors.
You get:
APIs designed along those rules; it adds no steps or files of its own.
Also covers:
Common pitfalls, such as breaking changes, inconsistent error formats and APIs that mirror the database schema.

TL;DR

It's a reference, not a workflow. For REST, resources are plural nouns and actions are HTTP methods; it spells out what GET, POST, PUT, PATCH and DELETE mean and which are idempotent, and asks for correct status codes, stateless requests, pagination of large collections, rate limits and OpenAPI docs. For GraphQL, it designs the schema before the resolvers, uses DataLoaders to avoid N+1 queries, validates at schema and resolver level, returns structured errors in mutation payloads, paginates with cursors and retires fields with @deprecated. It shows three ways to version an API, with an example each: in the URL, in a header or as a query parameter. A separate file holds detailed patterns and worked examples.

Summarizes the skill at 4bde316.

npx skills add https://github.com/wshobson/agents --skill api-design-principles

skills.sh pageSource on GitHubAll skills from wshobson/agents

Total Downloads
31,300 on skills.sh, Nov 9, 2026
Repo stars
42,334 wshobson/agents
First seen
Jan 20, 2026 on skills.sh
Weekly Downloads
372
+6% over the 8 weeks to Nov 9
Weekly values
Week toInstalls
Sep 21351
Sep 28401
Oct 5463
Oct 12400
Oct 19425
Oct 26411
Nov 2469
Nov 9372
Category
category:engineeringcategory:software-engineering

Test-first work, implementation from specs, git hygiene and scope control.

Everything for building software: planning, coding, debugging, design, frameworks, cloud, agents and skills.
Type
type:guidelines

Knowledge and rules the agent applies while it works: best practices, design principles, API references.
Effect
effect:none

Adds no side effects of its own. It shapes how the agent thinks, writes or reviews. Guidelines and routers are always effect:none, even when the task they support edits code.
Needs
needs:none

Instructions only. Works in any agent that supports skills.
Publisher
by:community

Everyone else. Unverified vendor claims default to community.
Topics
backendarchitecture
Stack
stack:graphql

SKILL.md

From wshobson/agents at 4bde316. Checked daily, last changed Nov 6, 2026.

Frontmatter
name: api-design-principles
description: Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers. Use when designing new APIs, reviewing API specifications, or establishing API design standards.

API Design Principles

Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers and stand the test of time.

When to Use This Skill

  • Designing new REST or GraphQL APIs
  • Refactoring existing APIs for better usability
  • Establishing API design standards for your team
  • Reviewing API specifications before implementation
  • Migrating between API paradigms (REST to GraphQL, etc.)
  • Creating developer-friendly API documentation
  • Optimizing APIs for specific use cases (mobile, third-party integrations)

Core Concepts

1. RESTful Design Principles

Resource-Oriented Architecture

  • Resources are nouns (users, orders, products), not verbs
  • Use HTTP methods for actions (GET, POST, PUT, PATCH, DELETE)
  • URLs represent resource hierarchies
  • Consistent naming conventions

HTTP Methods Semantics:

  • GET: Retrieve resources (idempotent, safe)
  • POST: Create new resources
  • PUT: Replace entire resource (idempotent)
  • PATCH: Partial resource updates
  • DELETE: Remove resources (idempotent)
2. GraphQL Design Principles

Schema-First Development

  • Types define your domain model
  • Queries for reading data
  • Mutations for modifying data
  • Subscriptions for real-time updates

Query Structure:

  • Clients request exactly what they need
  • Single endpoint, multiple operations
  • Strongly typed schema
  • Introspection built-in
3. API Versioning Strategies

URL Versioning:

/api/v1/users
/api/v2/users

Header Versioning:

Accept: application/vnd.api+json; version=1

Query Parameter Versioning:

/api/users?version=1

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

REST APIs
  1. Consistent Naming: Use plural nouns for collections (/users, not /user)
  2. Stateless: Each request contains all necessary information
  3. Use HTTP Status Codes Correctly: 2xx success, 4xx client errors, 5xx server errors
  4. Version Your API: Plan for breaking changes from day one
  5. Pagination: Always paginate large collections
  6. Rate Limiting: Protect your API with rate limits
  7. Documentation: Use OpenAPI/Swagger for interactive docs
GraphQL APIs
  1. Schema First: Design schema before writing resolvers
  2. Avoid N+1: Use DataLoaders for efficient data fetching
  3. Input Validation: Validate at schema and resolver levels
  4. Error Handling: Return structured errors in mutation payloads
  5. Pagination: Use cursor-based pagination (Relay spec)
  6. Deprecation: Use @deprecated directive for gradual migration
  7. Monitoring: Track query complexity and execution time

Common Pitfalls

  • Over-fetching/Under-fetching (REST): Fixed in GraphQL but requires DataLoaders
  • Breaking Changes: Version APIs or use deprecation strategies
  • Inconsistent Error Formats: Standardize error responses
  • Missing Rate Limits: APIs without limits are vulnerable to abuse
  • Poor Documentation: Undocumented APIs frustrate developers
  • Ignoring HTTP Semantics: POST for idempotent operations breaks expectations
  • Tight Coupling: API structure shouldn't mirror database schema