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

7 slash commands that map to the development lifecycle. Each one activates the right skills automatically.

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

/plugin marketplace add addyosmani/agent-skills
/plugin install agent-skills@addy-agent-skills

git clone https://github.com/addyosmani/agent-skills.git
claude --plugin-dir /path/to/agent-skills

gemini skills install https://github.com/addyosmani/agent-skills.git

All 19 Skills

The commands above are the entry points. Under the hood, they activate these 19 skills — each one a structured workflow with steps, verification gates, and anti-rationalization tables. You can also reference any skill directly.

Define - Clarify what to build

Plan - Break it down

Build - Write the code

Verify - Prove it works

Review - Quality gates before merge

Ship - Deploy with confidence

Agent Personas

Pre-configured specialist personas for targeted reviews:

Reference Checklists

Quick-reference material that skills pull in when needed:

How Skills Work

Every skill follows a consistent anatomy:

┌─────────────────────────────────────────────┐
│  SKILL.md                                   │
│                                             │
│  ┌─ Frontmatter ─────────────────────────┐  │
│  │ name: lowercase-hyphen-name           │  │
│  │ description: Use when [trigger]       │  │
│  └───────────────────────────────────────┘  │
│                                             │
│  Overview         → What this skill does    │
│  When to Use      → Triggering conditions   │
│  Process          → Step-by-step workflow   │
│  Rationalizations → Excuses + rebuttals     │
│  Red Flags        → Signs something's wrong │
│  Verification     → Evidence requirements   │
└─────────────────────────────────────────────┘

Key design choices:

• Process, not prose. Skills are workflows agents follow, not reference docs they read. Each has steps, checkpoints, and exit criteria.
• Anti-rationalization. Every skill includes a table of common excuses agents use to skip steps (e.g., "I'll add tests later") with documented counter-arguments.
• Verification is non-negotiable. Every skill ends with evidence requirements - tests passing, build output, runtime data. "Seems right" is never sufficient.
• Progressive disclosure. The SKILL.md is the entry point. Supporting references load only when needed, keeping token usage minimal.

Project Structure

agent-skills/
├── skills/                            # 19 core skills (SKILL.md per directory)
│   ├── idea-refine/                   #   Define
│   ├── spec-driven-development/       #   Define
│   ├── planning-and-task-breakdown/   #   Plan
│   ├── incremental-implementation/    #   Build
│   ├── context-engineering/           #   Build
│   ├── frontend-ui-engineering/       #   Build
│   ├── test-driven-development/       #   Build
│   ├── api-and-interface-design/      #   Build
│   ├── browser-testing-with-devtools/ #   Verify
│   ├── debugging-and-error-recovery/  #   Verify
│   ├── code-review-and-quality/       #   Review
│   ├── code-simplification/          #   Review
│   ├── security-and-hardening/        #   Review
│   ├── performance-optimization/      #   Review
│   ├── git-workflow-and-versioning/   #   Ship
│   ├── ci-cd-and-automation/          #   Ship
│   ├── deprecation-and-migration/     #   Ship
│   ├── documentation-and-adrs/        #   Ship
│   ├── shipping-and-launch/           #   Ship
│   └── using-agent-skills/            #   Meta: how to use this pack
├── agents/                            # 3 specialist personas
├── references/                        # 4 supplementary checklists
├── hooks/                             # Session lifecycle hooks
├── .claude/commands/                  # 7 slash commands
└── docs/                              # Setup guides per tool

Why Agent Skills?

AI coding agents default to the shortest path - which often means skipping specs, tests, security reviews, and the practices that make software reliable. Agent Skills gives agents structured workflows that enforce the same discipline senior engineers bring to production code.

Each skill encodes hard-won engineering judgment: when to write a spec, what to test, how to review, and when to ship. These aren't generic prompts - they're the kind of opinionated, process-driven workflows that separate production-quality work from prototype-quality work.

Skills bake in best practices from Google's engineering culture — including concepts from Software Engineering at Google and Google's engineering practices guide. You'll find Hyrum's Law in API design, the Beyonce Rule and test pyramid in testing, change sizing and review speed norms in code review, Chesterton's Fence in simplification, trunk-based development in git workflow, Shift Left and feature flags in CI/CD, and a dedicated deprecation skill treating code as a liability. These aren't abstract principles — they're embedded directly into the step-by-step workflows agents follow.

Contributing

Skills should be specific (actionable steps, not vague advice), verifiable (clear exit criteria with evidence requirements), battle-tested (based on real workflows), and minimal (only what's needed to guide the agent).

See docs/skill-anatomy.md for the format specification and CONTRIBUTING.md for guidelines.

License

MIT - use these skills in your projects, teams, and tools.