New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Common API Design

by HoangNguyen0403 in HoangNguyen0403/agent-skills-standard

Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework.

MITAuto-check passedBackend & APIs

Install Common API Design

skills CLI
$ npx skills add HoangNguyen0403/agent-skills-standard --skill common-api-design -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install HoangNguyen0403/agent-skills-standard common-api-design --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standard.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/common/common-api-design .claude/skills/common-api-design && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
common-api-design
GitHub stars
572
Token cost
~880 tokens
SKILL.md length
334 words
Files
3 (incl. references)
Skills in repo
211
Repo updated
First seen
Licence
MIT

At a glance

Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework.

  • Designing endpoints
  • SKILL.md covers Priority: P1 (HIGH), 🔧 HTTP Verb Semantics, 📡 Status Code Correctness and 📦 URL Design Rules, plus 7 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Choosing HTTP methods

What it does

Common API Design is an agent skill from HoangNguyen0403/agent-skills-standard. Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework. Use when designing endpoints, choosing HTTP methods, implementing pagination, or writing OpenAPI specs.

Its SKILL.md is about 880 tokens, which your agent loads only when the skill is triggered. The skill folder holds 4 other files, including reference files (for example `evals/evals.json` and `references/REFERENCE.md`).

It sits in Backend & APIs, covering OpenAPI specifications, API design and REST APIs. It works with OpenAPI. The repository describes itself as: A collection of Agent Skills Standard and Best Practice for Programming Languages, Frameworks that help our AI Agent follow best practies on frameworks and programming laguages. The licence is MIT.

When your agent uses it

  • Designing endpoints
  • Choosing HTTP methods
  • Implementing pagination
  • Writing OpenAPI specs

Example prompts

  • “/common-api-design”

What it can do on your machine

Read from SKILL.md and the folder at commit b529c2d. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Common API Design loads about 880 tokens when it runs, and up to ~1.3k if it reads all its reference files. Until then it costs about 61 tokens; SKILL.md has 334 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~61
When it runs · the whole SKILL.md, loaded when a task matches
~880
With references · SKILL.md plus every file in references/, read only if the agent opens them
~1.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from HoangNguyen0403/agent-skills-standard at commit b529c2d, republished under its MIT licence (© HoangNguyen0403). 334 words, ~880 tokens.

Download SKILL.mdSave it as .claude/skills/common-api-design/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.
name
common-api-design
description
Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework. Use when designing endpoints, choosing HTTP methods, implementing pagination, or writing OpenAPI specs.

Common API Design Standards

Priority: P1 (HIGH)

🔧 HTTP Verb Semantics

  • GET read-only, idempotent — never mutates state.
  • POST create or trigger; PUT full replace; PATCH partial update; DELETE remove.
  • Non-CRUD actions as sub-resources: POST /orders/:id/cancel.

📡 Status Code Correctness

  • 200 success; 201 created (add Location header); 204 no body.
  • 400 validation (with details[]); 401 unauthenticated; 403 unauthorized; 404 not found.
  • 409 conflict; 422 business rule violation; 429 rate limit (add Retry-After); 500 unhandled.

📦 URL Design Rules

  • Lowercase, kebab-case: /user-profiles, not /UserProfiles or /user_profiles.
  • Plural nouns: /orders, /products. Not /order, /getProducts.
  • No verbs in paths (except action sub-resources): /orders/:id/cancel ✅, /cancelOrder ❌.
  • Hierarchy: Use nesting only up to 2 levels: /users/:id/orders ✅, /users/:id/orders/:orderId/items/:itemId ❌.

🔢 API Versioning

  • Strategy: URL path versioning default: /v1/users, /v2/users.
  • Header versioning (Api-Version: 2) acceptable for internal APIs.
  • Never mix versions in same controller — each version gets its own route module.
  • Support prev major ≥ 6 months after new release.
  • Deprecation: Deprecation: true + Sunset: <date> headers when version will be retired.

📄 Pagination

  • Prefer cursor-based (cursor + limit) for large/live datasets; offset only for small static ones.
  • Default limit: 20, max 100. Reject requests exceeding max.
  • Response envelope: { data: [], pagination: { nextCursor, hasNextPage } }.

📝 OpenAPI Contract

  • Generate from code annotations — not hand-written YAML.
  • Every API needs OpenAPI 3.1 spec.
  • Include: request/response schemas, error shapes, auth requirements, examples.
  • Review spec in PR — breaking changes need version bump.

🔒 API Security Baseline

  • Require auth on all routes by default; use @Public() or equivalent opt-out.
  • Validate and sanitize all query params, path params, and request bodies.
  • Set Content-Type: application/json explicitly. Reject unexpected content types.
  • Include X-Content-Type-Options: nosniff and X-Frame-Options: DENY headers.

Anti-Patterns

  • No GET mutations: Search engines and CDNs cache GET — mutating state catastrophic.
  • No 200 for errors: { "success": false, "data": null } with HTTP 200 breaks monitoring.
  • No deeply nested URLs: Hard to document, version, and cache.
  • No breaking changes without versioning: Removing/renaming fields in-place breaks consumers silently.

References

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

  • DELETE

© HoangNguyen0403, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 2 other files (references) in skills/common/common-api-design of HoangNguyen0403/agent-skills-standard.

  • SKILL.md
  • evals/evals.json
  • references/REFERENCE.md

Open the folder on GitHubat commit b529c2d

Compare with similar skills

Common API Design next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Common API Design compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Common API Design this skillHoangNguyen0403/agent-skills-standard572—~880Automated safety check: PassMIT
API DesignerJeffallan/claude-skills12k1 repos~2kAutomated safety check: PassMIT
Old Coder API DesignAmazingAng/old-coder750—~3.4kAutomated safety check: PassMIT
OpenAPI Spec Generationwshobson/agents40k9 repos~511Automated safety check: PassMIT
API Design Patternsrohitg00/awesome-claude-code-toolkit2.7k—~1.2kAutomated safety check: PassApache-2.0
API Contract Designrsmdt/the-startup560—~1.1kAutomated safety check: PassMIT

Similar skills

  • API Designer

    Jeffallan/claude-skills

    Designs REST and GraphQL APIs from resource modeling to an OpenAPI 3.1 contract, with versioning, pagination and RFC 7807 error handling.

    12k GitHub starsUsed in 1 repo~2k tokens
    Backend & APIsAuto-check passed

  • Old Coder API Design

    AmazingAng/old-coder

    Reviews or designs an HTTP/JSON API's endpoints, auth, pagination, versioning and deprecations, guarding against inventing a bespoke interface or silently breaking consumers.

    750 GitHub stars~3.4k tokensUpdated 1 mo ago
    Backend & APIsAuto-check passed

  • OpenAPI Spec Generation

    wshobson/agents

    Create, validate and maintain OpenAPI 3.1 specs for REST APIs, whether designed first or generated from existing code, and use them for docs and client SDKs.

    40k GitHub starsUsed in 9 repos~511 tokens
    Backend & APIsAuto-check passed

  • API Design Patterns

    rohitg00/awesome-claude-code-toolkit

    REST API design with resource naming, pagination, versioning, and OpenAPI spec generation

    2.7k GitHub stars~1.2k tokensUpdated 5 mo ago
    Backend & APIsAuto-check passed

  • API Contract Design

    rsmdt/the-startup

    REST and GraphQL API design patterns, OpenAPI/Swagger specifications, versioning strategies, and authentication patterns.

    560 GitHub stars~1.1k tokensUpdated 2 mo ago
    Backend & APIsAuto-check passed

  • API Design

    epam/ai-dial-chat

    Design, review, or change HTTP API contracts for AI DIAL Chat.

    504 GitHub stars~1.2k tokensUpdated yesterday
    Backend & APIsAuto-check passed

More from HoangNguyen0403/agent-skills-standard

All 211 skills in this repo

  • Subagent-Driven Development

    HoangNguyen0403/agent-skills-standard

    Runs a multi-task implementation plan by sending each task to a fresh implementer subagent, reviewing it independently, then reviewing the whole branch.

    572 GitHub stars~1.3k tokensUpdated yesterday
    Auto-check passed

  • draw.io Architecture Diagramming

    HoangNguyen0403/agent-skills-standard

    Draws architecture diagrams as editable draw.io files from a JSON spec, with a fixed house style, one C4 level per diagram and evidence-tagged shapes.

    572 GitHub stars~1.3k tokensUpdated yesterday
    Auto-check passed

  • Android Navigation 3 Guide

    HoangNguyen0403/agent-skills-standard

    Implements and migrates to Jetpack Navigation 3 in Compose: NavDisplay, typed route objects, a state-list back stack, deep links, multiple back stacks and dialog scenes.

    572 GitHub stars~687 tokensUpdated yesterday
    Auto-check passed

  • Angular HttpClient Standards

    HoangNguyen0403/agent-skills-standard

    Sets rules for Angular HTTP code: functional interceptors, typed requests, services that own every call, and httpResource for reactive data loading in Angular 17+.

    572 GitHub stars~652 tokensUpdated yesterday
    Auto-check passed

  • Angular Tooling

    HoangNguyen0403/agent-skills-standard

    Angular CLI usage, code generation, build configuration, and bundle optimization.

    572 GitHub stars~743 tokensUpdated yesterday
    Auto-check passed

  • Common Code Review

    HoangNguyen0403/agent-skills-standard

    Conduct high-quality, persona-driven code reviews. An agent skill from HoangNguyen0403/agent-skills-standard.

    572 GitHub stars~772 tokensUpdated yesterday
    Auto-check passed

Works with

Categories

Questions about Common API Design

What does Common API Design do?

Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework. Common API Design is an agent skill from HoangNguyen0403/agent-skills-standard. Apply REST API conventions — HTTP semantics, status codes, versioning, pagination, and OpenAPI standards for any framework.

When should I use Common API Design?

Common API Design fits situations like: designing endpoints; choosing HTTP methods; implementing pagination; writing OpenAPI specs.

How do I install Common API Design in Claude Code?

Run `npx skills add HoangNguyen0403/agent-skills-standard --skill common-api-design -a claude-code`. Or copy the skill folder (skills/common/common-api-design in HoangNguyen0403/agent-skills-standard) into .claude/skills/common-api-design in your project. Claude Code loads it when a task matches its description.

How do I install Common API Design in Codex?

Run `npx skills add HoangNguyen0403/agent-skills-standard --skill common-api-design -a codex`. Or copy the skill folder (skills/common/common-api-design in HoangNguyen0403/agent-skills-standard) into .agents/skills/common-api-design in your project. Codex loads it when a task matches its description.

Can I use Common API Design in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add HoangNguyen0403/agent-skills-standard --skill common-api-design -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/common-api-design, .gemini/skills/common-api-design, .github/skills/common-api-design and .opencode/skills/common-api-design in your project.

What does Common API Design need to run?

SKILL.md names no scripts, command-line tools or credentials: Common API Design is instructions for the agent only.

Does Common API Design access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Common API Design safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Common API Design use?

Common API Design is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Common API Design use?

About 880 tokens (SKILL.md is roughly 3.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 383 tokens, read only when the agent opens those files.

What are the alternatives to Common API Design?

Skills that share tags, products or a category with Common API Design: API Designer (Jeffallan/claude-skills, 12k stars), Old Coder API Design (AmazingAng/old-coder, 750 stars), OpenAPI Spec Generation (wshobson/agents, 40k stars) and API Design Patterns (rohitg00/awesome-claude-code-toolkit, 2.7k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Common API Design?

HoangNguyen0403 (a GitHub user) maintains it in HoangNguyen0403/agent-skills-standard, which has 572 GitHub stars. The repository holds 211 skills in this directory. The repository was last updated on October 9, 2026.

Source: HoangNguyen0403/agent-skills-standard on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.