Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .claude/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
skills CLI
$ npx skills add agulli/atlas-agents --skill api-design -a codex
Project install goes to .agents/skills/; add -g for ~/.codex/skills/.
Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .agents/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
skills CLI
$ npx skills add agulli/atlas-agents --skill api-design -a cursor
Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.
Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .cursor/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
skills CLI
$ npx skills add agulli/atlas-agents --skill api-design -a gemini-cli
Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.
Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .gemini/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
GitHub CLI
$ gh skill install agulli/atlas-agents api-design
Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
skills CLI
$ npx skills add agulli/atlas-agents --skill api-design -a github-copilot
Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.
Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .github/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
skills CLI
$ npx skills add agulli/atlas-agents --skill api-design -a opencode
OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
Install the "api-design" agent skill from https://github.com/agulli/atlas-agents/tree/main/ch09_agent_skills/skills/api-design into .opencode/skills/api-design/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-design", then confirm the skill loads.
OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
Skill name
api-design
GitHub stars
578
Token cost
~539 tokens
SKILL.md length
257 words
Files
1
Skills in repo
12
Repo updated
First seen
Licence
MIT
At a glance
Design or review REST and GraphQL API interfaces. An agent skill from agulli/atlas-agents.
Works in 6 steps: Identify the domain objects. List every… → Design the resource hierarchy. Use… → Define schemas. Write request and… → …
Asked to design an API
SKILL.md covers Overview, Process, Rationalizations and Verification
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
API Design is an agent skill from agulli/atlas-agents. Design or review REST and GraphQL API interfaces. Use when asked to design an API, review endpoint structure, define request/response schemas, or improve API ergonomics.
Its SKILL.md is about 540 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Backend & APIs, covering API design and GraphQL. It works with GraphQL. The licence is MIT.
When your agent uses it
Asked to design an API
Review endpoint structure
Define request/response schemas
Improve API ergonomics
Example prompts
“/api-design”
Workflow steps
6 steps, taken from the first numbered list in SKILL.md.
1Identify the domain objects. List every noun the API needs to represent. Group them by relationship.
2Design the resource hierarchy. Use plural nouns for collections: /users, /users/{id}/orders. Never use verbs in URLs — the HTTP method IS…
3Define schemas. Write request and response schemas as JSON examples. Every field must have
4Error contract. Define a consistent error envelope
5Pagination. All list endpoints must support cursor-based pagination by default. Offset pagination is acceptable only if explicitly…
6Versioning. Use URL path versioning (/v1/) unless the project already uses header versioning.
What it can do on your machine
Read from SKILL.md and the folder at commit 2b21998. 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 (its code samples are json).
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
API Design loads about 539 tokens when it runs. Until then it costs about 45 tokens; SKILL.md has 257 words of instructions outside code blocks.
Always· name and description, kept in context so the agent knows when to use it
~45
When it runs· the whole SKILL.md, loaded when a task matches
~539
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.
Download SKILL.mdSave it as .claude/skills/api-design/SKILL.md (or your agent's skills folder).
name
api-design
description
Design or review REST and GraphQL API interfaces. Use when asked to design an API, review endpoint structure, define request/response schemas, or improve API ergonomics.
license
MIT
Overview
You are designing APIs that other developers — and other agents — will consume. Clarity and predictability matter more than cleverness.
Process
Identify the domain objects. List every noun the API needs to represent. Group them by relationship.
Design the resource hierarchy. Use plural nouns for collections: /users, /users/{id}/orders. Never use verbs in URLs — the HTTP method IS the verb.
Define schemas. Write request and response schemas as JSON examples. Every field must have:
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.
Build production-ready Node.js backend services with Express/Fastify, implementing middleware patterns, error handling, authentication, database integration, and API design best practices.
Design or review REST and GraphQL API interfaces. An agent skill from agulli/atlas-agents. API Design is an agent skill from agulli/atlas-agents. Design or review REST and GraphQL API interfaces.
When should I use API Design?
API Design fits situations like: asked to design an API; review endpoint structure; define request/response schemas; improve API ergonomics.
How do I install API Design in Claude Code?
Run `npx skills add agulli/atlas-agents --skill api-design -a claude-code`. Or copy the skill folder (ch09_agent_skills/skills/api-design in agulli/atlas-agents) into .claude/skills/api-design in your project. Claude Code loads it when a task matches its description.
How do I install API Design in Codex?
Run `npx skills add agulli/atlas-agents --skill api-design -a codex`. Or copy the skill folder (ch09_agent_skills/skills/api-design in agulli/atlas-agents) into .agents/skills/api-design in your project. Codex loads it when a task matches its description.
Can I use 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 agulli/atlas-agents --skill 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/api-design, .gemini/skills/api-design, .github/skills/api-design and .opencode/skills/api-design in your project.
What does API Design need to run?
SKILL.md names no scripts, command-line tools or credentials: API Design is instructions for the agent only.
Does 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 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 API Design use?
API Design is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does API Design use?
About 539 tokens (SKILL.md is roughly 2.2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to API Design?
Skills that share tags, products or a category with API Design: API Designer (Jeffallan/claude-skills, 12k stars), Nodejs Backend Patterns (ever-works/ever-works, 158 stars), API And Interface Design (dzhalaevd/Donatello, 135 stars) and API Design Principles (jh941213/my-cc-harness, 126 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains API Design?
agulli (a GitHub user) maintains it in agulli/atlas-agents, which has 578 GitHub stars. The repository holds 12 skills in this directory. The repository was last updated on July 17, 2026.
Source: agulli/atlas-agents on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.
