Is the API Expert skill free?

Yes. The skill itself is free from martinholovsky/claude-skills-generator. SkillProof publishes the install command and an independent test verdict at no cost.

What is the API Expert SkillProof Score?

9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 5/5.

How do I install API Expert?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use API Expert with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

API Expert

REST/GraphQL/gRPC API design playbook with OWASP API Top 10 mitigations, RFC 7807 errors, and TDD-first endpoint patterns.

by martinholovsky · martinholovsky/claude-skills-generator

Tested · Works

Install — copy the command Download source ↗

Test report

Verdict: Tested · Works
Score: 9.2/10
Tested: Jul 14, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 1b12e58

Had it design a versioned /v1/orders API: it produced cursor pagination, RFC 7807 error bodies, and an explicit BOLA test (403 when a user requests another user's order) that a baseline design skipped entirely and left as a generic 400/500 error shape.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 8/10
Docs & honesty 5/5

What API Expert does

api-expert equips Claude with a concrete API-architecture checklist: REST resource naming, correct HTTP status codes, OAuth2/JWT (RS256) auth, cursor-based pagination, rate limiting, and OWASP API Security Top 10 mitigations (BOLA, mass assignment, SSRF, etc.), backed by runnable Node/Python examples. Trigger it when designing new API endpoints, an API gateway, or auditing an existing API's security and error-handling conventions.

How to install API Expert

git clone https://github.com/martinholovsky/claude-skills-generator
cd claude-skills-generator
mkdir -p ~/.claude/skills
cp -r skills/api-expert ~/.claude/skills/api-expert

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger API Expert

/api-expert REST/GraphQL/gRPC API design playbook with OWASP API Top 10 mitigations, RFC 7807 errors, and TDD-first endpoint patterns.

It also activates on plain-language prompts like these:

Design REST endpoints for an orders resource with pagination
Add rate limiting and OWASP protections to our public API
What's the safest way to paginate a GraphQL API with huge tables

Frequently asked questions

Is the API Expert skill free?: Yes. The skill itself is free from martinholovsky/claude-skills-generator. SkillProof publishes the install command and an independent test verdict at no cost.
Does API Expert work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 14, 2026. Verdict: Tested · Works. Had it design a versioned /v1/orders API: it produced cursor pagination, RFC 7807 error bodies, and an explicit BOLA test (403 when a user requests another user's order) that a baseline design skipped entirely and left as a generic 400/500 error shape.
What is the API Expert SkillProof Score?: 9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 5/5.
How do I install API Expert?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use API Expert with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.