Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/addyosmani/agent-skills/claude-mdgit clone --depth 1 https://github.com/addyosmani/agent-skillsWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00909 | $0.00909 |
| Opus 5 | $0.00454 | $0.00454 |
| Sonnet 5 | $0.00182 | $0.00182 |
| Haiku 4.5 | $0.00091 | $0.00091 |
Grade A, and why
agent-skills CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.
agent-skills
This is the agent-skills project — a collection of production-grade engineering skills for AI coding agents.
Scope: This file configures agents working on the
addyosmani/agent-skillsrepository itself, not other projects. Don't copy it into another project or a global agent configuration; the reusable assets are the skills inskills/.
Project Structure
skills/ → Core skills (SKILL.md per directory)
agents/ → Reusable agent personas (code-reviewer, test-engineer, security-auditor, web-performance-auditor)
hooks/ → Session lifecycle hooks
.claude/commands/ → Slash commands (/spec, /plan, /build, /test, /review, /code-simplify, /ship; plus /webperf specialist audit)
references/ → Supplementary checklists (testing, performance, security, accessibility, observability)
evals/ → Skill eval cases + framework (see evals/README.md)
docs/ → Setup guides for different tools
Skills by Phase
Define: interview-me, idea-refine, spec-driven-development Plan: planning-and-task-breakdown Build: incremental-implementation, test-driven-development, context-engineering, source-driven-development, doubt-driven-development, frontend-ui-engineering, api-and-interface-design Verify: browser-testing-with-devtools, debugging-and-error-recovery Review: code-review-and-quality, code-simplification, security-and-hardening, performance-optimization Ship: git-workflow-and-versioning, ci-cd-and-automation, deprecation-and-migration, documentation-and-adrs, observability-and-instrumentation, shipping-and-launch
Conventions
- Every skill lives in
skills/<name>/SKILL.md - YAML frontmatter with
nameanddescriptionfields - Description starts with what the skill does (third person), followed by trigger conditions ("Use when...")
- Every skill has: Overview, When to Use, Process, Common Rationalizations, Red Flags, Verification
- Shared references are in the root
references/directory; the emerging convention for self-contained, distributable skills keeps a skill's own references insideskills/<name>/references/ - Supporting files only created when content exceeds 100 lines
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 61 lines · 909 tokens per session scan A f03b7aaf2c08
agent-skills CLAUDE.md is an instructions file published in the GitHub repository addyosmani/agent-skills (90,889 stars, last pushed 3d ago), licensed MIT. It adds 909 tokens to every session, about $0.0045 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
agent-skills AGENTS.md
Instructions for helderberto/agent-skills, covering agents.md, repository overview, project structure, integration model and opencode integration.
SkillEngine AGENTS.md
Instructions for borhen68/SkillEngine, covering agents.md, repository overview, opencode integration, core rules and intent → skill mapping.
ai-agent-skills AGENTS.md
Instructions for DevelopersGlobal/ai-agent-skills, covering ai agent instructions for this repository, when working in this repository, repository structure, key principles and when adding a new skill.
SkillEngine CLAUDE.md
Instructions for borhen68/SkillEngine, covering skillengine, project structure, skills by phase, conventions and commands.
addyosmani-agent-skills-zh AGENTS.md
Instructions for vinvcn/addyosmani-agent-skills-zh, covering agents.md, 仓库概览, opencode 集成, 核心规则 and 意图 → skill 映射.
addyosmani-agent-skills-zh CLAUDE.md
Instructions for vinvcn/addyosmani-agent-skills-zh, covering agent-skills, 项目结构, 按阶段划分的 skills, 约定 and 命令.