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api-and-interface-design
Guides stable API and interface design. Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints, defining type contracts between modules, or establishing boundaries between frontend and backend.
// RATINGS
// README
Agent Skills
Production-grade engineering skills for AI coding agents.
Skills encode the workflows, quality gates, and best practices that senior engineers use when building software. These ones are packaged so AI agents follow them consistently across every phase of development.

DEFINE PLAN BUILD VERIFY REVIEW SHIP
┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐
│ Idea │ ───▶ │ Spec │ ───▶ │ Code │ ───▶ │ Test │ ───▶ │ QA │ ───▶ │ Go │
│Refine│ │ PRD │ │ Impl │ │Debug │ │ Gate │ │ Live │
└──────┘ └──────┘ └──────┘ └──────┘ └──────┘ └──────┘
/spec /plan /build /test /review /ship
Commands
9 slash commands that map to the development lifecycle. Each one activates the right skills automatically.
| What you're doing | Command | Key principle |
|---|---|---|
| Define what to build | /spec | Spec before code |
| Plan how to build it | /plan | Small, atomic tasks |
| Build incrementally | /build | One slice at a time |
| Prove it works | /test | Tests are proof |
| Set the quality bar | /constraints | Decide it once, enforce it everywhere |
| Review before merge | /review | Improve code health |
| Audit web performance | /webperf | Measure before you optimize |
| Simplify the code | /code-simplify | Clarity over cleverness |
| Ship to production | /ship | Faster is safer |
Want fewer manual steps once the spec exists? /build auto generates the plan and implements every task in a single approved pass — you approve the plan once, then it runs autonomously. It removes the human stepping between tasks, not the verification: every task is still test-driven and committed individually, and it pauses on failures or risky steps.
Skills also activate automatically based on what you're doing — designing an API triggers api-and-interface-design, building UI triggers frontend-ui-engineering, and so on.
Quick Start
Fastest path — any agent, one command. The open skills CLI installs into 70+ agents (Claude Code, Cursor, Codex, Copilot, Cline, and more):
npx skills add addyosmani/agent-skills # install all 25 skills
npx skills add addyosmani/agent-skills --list # browse before installing
Or grab individual skills:
npx skills add addyosmani/agent-skills --skill code-review-and-quality # five-axis review before merge
npx skills add addyosmani/agent-skills --skill interview-me # requirements interrogation, one question at a time
npx skills add addyosmani/agent-skills --skill test-driven-development # red-green-refactor, enforced
Installing one skill? A per-skill
npxinstall copies onlyskills/<name>/, not the repo-levelreferences/directory. The skill still works, but paths to supplementary shared checklists are unavailable. Use a whole-repo integration, clone the repository, or copy the needed checklist into areferences/directory inside the installed skill. This portability gap is tracked in #361.
Prefer a native integration? Pick your tool below.
Marketplace install:
/plugin marketplace add addyosmani/agent-skills
/plugin install agent-skills@addy-agent-skills
SSH errors? The marketplace clones repos via SSH. If you don't have SSH keys set up on GitHub, either add your SSH key or use the full HTTPS URL to force HTTPS cloning during the marketplace-add step:
/plugin marketplace add https://github.com/addyosmani/agent-skills.git /plugin install agent-skills@addy-agent-skillsIf
/plugin installstill fails with[email protected]: Permission denied (publickey)on Windows or macOS, the recommended workaround is to configure Git once to rewrite GitHub SSH URLs to HTTPS for subprocess clones:git config --global url."https://github.com/".insteadOf [email protected]:
Local / development:
git clone https://github.com/addyosmani/agent-skills.git
claude --plugin-dir /path/to/agent-skills
Put workflow skills under .cursor/skills/ (sync from agent-skills/skills/) and short policies in .cursor/rules/*.mdc — do not paste full skills into rules. See docs/cursor-setup.md.
Install as a native plugin for skills and subagents. In affected Antigravity CLI releases, legacy command TOMLs are reported as converted but their wrapper commands are not discoverable; invoke the underlying namespaced skills directly. See docs/antigravity-setup.md.
Install from the repo:
agy plugin install https://github.com/addyosmani/agent-skills.git
Install from a local clone:
git clone https://github.com/addyosmani/agent-skills.git
agy plugin install ./agent-skills
Install as native skills for auto-discovery, or add to GEMINI.md for persistent context. See docs/gemini-cli-setup.md.
Install from the repo:
gemini skills install https://github.com/addyosmani/agent-skills.git --path skills
Install from a local clone:
gemini skills install ./agent-skills/skills/
Add skill contents to your Windsurf rules configuration. See docs/windsurf-setup.md.
Copy skills to .opencode/skills/ (or ~/.config/opencode/skills/), add a project-local AGENTS.md, and use the built-in skill tool for agent-driven execution. Optional slash commands can be added under .opencode/commands/.
Use agent definitions from agents/ as Copilot personas and skill content in .github/copilot-instructions.md. See docs/copilot-setup.md.
Using the standalone copilot CLI? Install it as a plugin — see docs/copilot-cli-setup.md.
Install as a native Codex plugin (Codex CLI v0.122+):
codex plugin marketplace add addyosmani/agent-skills
codex plugin add agent-skills@agent-skills
The first command registers the marketplace; the second installs the plugin. Codex reads the root skills/ directory directly through .codex-plugin/plugin.json. Once installed, invoke skills in chat using @ (e.g., @spec-driven-development). See docs/codex-setup.md for local installation and troubleshooting.
Install natively with the built-in cmd skills command. Command Code clones the repo, discovers every SKILL.md, and installs into `.commandc
// HOW IT'S BUILT
KEY FILES