Agent Skills

Addy Osmani's skill library for AI coding agents: 25 engineering skills and 9 slash commands enforcing senior engineering workflows.

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The gist

Addy Osmani's production-grade skill library for AI coding agents: 25 skills encoding the workflows and quality gates senior engineers use across the full development lifecycle (DEFINE → PLAN → BUILD → VERIFY → REVIEW → SHIP). Mapped through 9 slash commands, it turns generic AI coding assistants into disciplined software engineering partners.

What it does

  • Encodes 25 engineering skills covering API design, testing, performance, security, and shipping workflows.
  • Automates disciplined engineering passes via 9 slash commands including /spec, /plan, /build, /test, and /review.
  • Auto-activates contextual skills based on ongoing work, such as interface design or frontend engineering.
  • Supports automated multi-task execution with /build auto, committing and testing each atomic task while pausing on risk.
  • Installs via open skills CLI (npx skills add addyosmani/agent-skills) targeting 70+ agent environments including Claude Code, Cursor, and Codex.

How it works

Architecture Diagram
Agent Skills Architecture Diagram

You install the skill package into your agent via npx or as a plugin. When starting tasks, skills auto-activate from context, or you trigger workflows directly via slash commands. The agent generates specifications before writing code, breaks work into atomic tasks, writes tests as proof, enforces architectural constraints, and verifies quality before shipping.

Best for

  • Developers and teams wanting to enforce senior engineering discipline, testing, and review across AI agent workflows.
  • Engineers using Claude Code, Cursor, Codex, or Cline who want standardized lifecycle slash commands.
  • Teams seeking automated spec-driven and test-driven development guardrails without manual prompting ceremony.

Watch out for

  • Fast-moving library with 177 open issues; community contributions and specifications evolve rapidly rather than following a frozen standard.
  • Single-skill installs via npx copy only the skill directory and miss repo-level reference checklists (issue #361); full-repo installation is recommended.
  • CLI installation requires Node/npx; the Claude Code plugin route namespaces clashing commands (e.g. /agent-skills:review).
  • Highly opinionated process: if your team does not adopt spec-before-code and tests-are-proof principles, the commands produce unnecessary ceremony.

What you need: Install it on your own computer. Cost: free, open source (MIT).