Is the API Design Principles skill free?

Yes. The skill itself is free from wshobson/agents. SkillProof publishes the install command and an independent test verdict at no cost.

How do I install API Design Principles?

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 Design Principles 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 Design Principles

Applies REST and GraphQL design principles to build clear, scalable APIs.

by wshobson · wshobson/agents

Tested · Didn't pass

Read why it failed Download source ↗

Test report

Verdict: Tested · Didn't pass
Tested: Jul 11, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · e914fb4

Tested a REST design task (bookmarking service: endpoints, versioning, pagination, JSON examples) with and without the skill. Both arms produced correct, complete designs with resource-oriented endpoints and URL versioning; the skill arm was fully best-practice-compliant but chose offset/page pagination, while the base arm independently reached the stronger cursor-based choice with sharper rationale. Verbatim install and frontmatter were clean; the skill adds no measurable lift over a capable base model on this task.

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 4/10
Docs & honesty 4/5

What API Design Principles does

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.

How to install API Design Principles

git clone https://github.com/wshobson/agents
cd agents
mkdir -p ~/.claude/skills
cp -r plugins/backend-development/skills/api-design-principles ~/.claude/skills/api-design-principles

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

Commands — how to trigger API Design Principles

/api-design-principles Applies REST and GraphQL design principles to build clear, scalable APIs.

It also activates on plain-language prompts like these:

Review this REST API design for consistency issues
Design a GraphQL schema following best practices
Set API design standards for our new service

Frequently asked questions

Is the API Design Principles skill free?: Yes. The skill itself is free from wshobson/agents. SkillProof publishes the install command and an independent test verdict at no cost.
Does API Design Principles work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 11, 2026. Verdict: Tested · Didn't pass. Tested a REST design task (bookmarking service: endpoints, versioning, pagination, JSON examples) with and without the skill. Both arms produced correct, complete designs with resource-oriented endpoints and URL versioning; the skill arm was fully best-practice-compliant but chose offset/page pagination, while the base arm independently reached the stronger cursor-based choice with sharper rationale. Verbatim install and frontmatter were clean; the skill adds no measurable lift over a capable base model on this task.
How do I install API Design Principles?: 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 Design Principles 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.