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.
Design and document RESTful and GraphQL APIs with OpenAPI/Swagger specifications, authentication patterns, versioning strategies, and best practices.
Install API Designer
$ npx skills add aiskillstore/marketplace --skill api-designer -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install aiskillstore/marketplace api-designer --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/autumnsgrove/api-designer .claude/skills/api-designer && rm -rf skills-srcUse ~/.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/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .claude/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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.
$skill-installer install https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designerType 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.
$ npx skills add aiskillstore/marketplace --skill api-designer -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install aiskillstore/marketplace api-designer --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/autumnsgrove/api-designer .agents/skills/api-designer && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .agents/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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.
$ npx skills add aiskillstore/marketplace --skill api-designer -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install aiskillstore/marketplace api-designer --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/autumnsgrove/api-designer .cursor/skills/api-designer && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .cursor/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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.
$ gemini skills install https://github.com/aiskillstore/marketplace.git --path skills/autumnsgrove/api-designer--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add aiskillstore/marketplace --skill api-designer -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install aiskillstore/marketplace api-designer --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/autumnsgrove/api-designer .gemini/skills/api-designer && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .gemini/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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.
$ gh skill install aiskillstore/marketplace api-designerInstalls 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).
$ npx skills add aiskillstore/marketplace --skill api-designer -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/autumnsgrove/api-designer .github/skills/api-designer && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .github/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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.
$ npx skills add aiskillstore/marketplace --skill api-designer -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install aiskillstore/marketplace api-designer --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/autumnsgrove/api-designer .opencode/skills/api-designer && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "api-designer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/autumnsgrove/api-designer into .opencode/skills/api-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "api-designer", 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-designer- GitHub stars
- 430
- Used in
- 1 other repo
- Token cost
- ~3.6k tokens
- SKILL.md length
- 1,021 words
- Files
- 10 (incl. scripts, references)
- Skills in repo
- 1,108
- Repo updated
- First seen
- Licence
- None found
At a glance
Design and document RESTful and GraphQL APIs with OpenAPI/Swagger specifications, authentication patterns, versioning strategies, and best practices.
- Works in 9 steps: Identify Resources → Design URL Structure → Choose HTTP Methods → …
- Creating API specifications
- SKILL.md covers Overview, Core Capabilities, When to Use This Skill and REST API Design Workflow, plus 4 more sections
- Runs Python scripts from its folder; calls python
What it does
API Designer is an agent skill from aiskillstore/marketplace. Design and document RESTful and GraphQL APIs with OpenAPI/Swagger specifications, authentication patterns, versioning strategies, and best practices. Use for: (1) Creating API specifications, (2) Designing REST endpoints, (3) GraphQL schema design, (4) API authentication and authorization, (5) API versioning strategies, (6) Documentation generation
Its SKILL.md is about 3.6k tokens, which your agent loads only when the skill is triggered. The skill folder holds 12 other files, including scripts and reference files (for example `README.md`, `examples/openapi_spec.yaml` and `references/authentication.md`).
It sits in Backend & APIs, covering OpenAPI specifications, GraphQL and REST APIs. It works with OpenAPI and GraphQL. The repository describes itself as: Security-audited skills for Claude, Codex & Claude Code. One-click install, quality verified.
When your agent uses it
- Creating API specifications
- Designing REST endpoints
- GraphQL schema design
- API authentication and authorization
Example prompts
- “/api-designer”
Requirements
- Python 3
Workflow steps
9 steps, taken from the step headings in SKILL.md.
- Identify Resources
- Design URL Structure
- Choose HTTP Methods
- Design Request/Response Payloads
- Implement Error Handling
- Add Pagination and Filtering
- Define Schema Types
- Design Queries
- Design Mutations
What it can do on your machine
Read from SKILL.md and the folder at commit ad8daf7. 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
Ships 1 file in scripts/ (Python), which the agent can run.
Shell commands in SKILL.md call:
python
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 Designer loads about 3.6k tokens when it runs, and up to ~17k if it reads all its reference files. Until then it costs about 91 tokens; SKILL.md has 1,021 words of instructions outside code blocks.
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); the scripts in this folder are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 1,021 words (~3,588 tokens).
“This skill provides comprehensive guidance for designing, documenting, and implementing modern APIs. It covers both REST and GraphQL paradigms, with emphasis on industry best practices, clear documentation, and maintainable architecture. Use this skill to create production-ready API designs that are…”
- name
- api-designer
Files
SKILL.md and 9 other files (scripts, references) in skills/autumnsgrove/api-designer of aiskillstore/marketplace.
- SKILL.md
- README.md
- examples/graphql_schema.graphql
- examples/openapi_spec.yaml
- references/authentication.md
- references/common-patterns.md
- references/rest_best_practices.md
- references/versioning-strategies.md
- scripts/api_helper.py
- skill-report.json
Open the folder on GitHubat commit ad8daf7
Used in 1 other repository
We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in aiskillstore/marketplace, which our catalogue first saw on October 7, 2026.
Compare with similar skills
API Designer 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| API Designer this skillaiskillstore/marketplace | 430 | 1 repos | ~3.6k | Automated safety check: Pass | None | |
| API DesignerJeffallan/claude-skills | 12k | 2 repos | ~2k | Automated safety check: Pass | MIT | |
| Discover APIrand/cc-polymath | 181 | 1 repos | ~1.5k | Automated safety check: Pass | MIT | |
| API Contract Designrsmdt/the-startup | 551 | — | ~1.1k | Automated safety check: Pass | MIT | |
| API Architectcuriositech/some_claude_skills | 243 | 1 repos | ~1.4k | Automated safety check: Pass | MIT | |
| API Designermajiayu000/claude-skill-registry | 666 | 1 repos | ~3.5k | Automated safety check: Pass | MIT |
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Related
Categories
Questions about API Designer
What does API Designer do?
Design and document RESTful and GraphQL APIs with OpenAPI/Swagger specifications, authentication patterns, versioning strategies, and best practices. API Designer is an agent skill from aiskillstore/marketplace. Design and document RESTful and GraphQL APIs with OpenAPI/Swagger specifications, authentication patterns, versioning strategies, and best practices.
When should I use API Designer?
API Designer fits situations like: creating API specifications; designing REST endpoints; graphQL schema design; API authentication and authorization.
How do I install API Designer in Claude Code?
Run `npx skills add aiskillstore/marketplace --skill api-designer -a claude-code`. Or copy the skill folder (skills/autumnsgrove/api-designer in aiskillstore/marketplace) into .claude/skills/api-designer in your project. Claude Code loads it when a task matches its description.
How do I install API Designer in Codex?
Run `npx skills add aiskillstore/marketplace --skill api-designer -a codex`. Or copy the skill folder (skills/autumnsgrove/api-designer in aiskillstore/marketplace) into .agents/skills/api-designer in your project. Codex loads it when a task matches its description.
Can I use API Designer 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 aiskillstore/marketplace --skill api-designer -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-designer, .gemini/skills/api-designer, .github/skills/api-designer and .opencode/skills/api-designer in your project.
What does API Designer need to run?
Going by SKILL.md and its folder, API Designer needs Python for the scripts in its folder and the command-line tools its instructions call (python). Our summary lists: Python 3.
Does API Designer 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 Designer 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. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does API Designer use?
No licence was found for API Designer or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does API Designer use?
About 3.6k tokens (SKILL.md is roughly 14k 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 13k tokens, read only when the agent opens those files.
What are the alternatives to API Designer?
Skills that share tags, products or a category with API Designer: API Designer (Jeffallan/claude-skills, 12k stars), Discover API (rand/cc-polymath, 181 stars), API Contract Design (rsmdt/the-startup, 551 stars) and API Architect (curiositech/some_claude_skills, 243 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains API Designer?
aiskillstore (a GitHub organization) maintains it in aiskillstore/marketplace, which has 430 GitHub stars. The repository holds 1,108 skills in this directory. The repository was last updated on October 7, 2026.
Source: aiskillstore/marketplace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.