addyosmani/agent-skills is a collection of reusable workflows, quality checks, commands, and other instructions that guide AI coding agents through software development. It is for developers who want agents to follow consistent engineering practices, and the catalogue entries are its packaged skills, commands, agents, plugins, instructions, and hooks.
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.
git clone --depth 1 https://github.com/addyosmani/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/commands/addyosmani/agent-skills/plan)<a href="https://agentmods.dev/commands/addyosmani/agent-skills/plan"><img src="https://agentmods.dev/badge/commands/addyosmani/agent-skills/plan/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/commands/addyosmani/agent-skills/plan"><img src="https://agentmods.dev/badge/commands/addyosmani/agent-skills/plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00013 | $0.00164 |
| Opus 5.5 | $0.00005 | $0.00066 |
| Sonnet 5.5 | $0.00003 | $0.00033 |
| Haiku 4.5 | $0.00001 | $0.00016 |
Grade A, and why
plan 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 1mo ago.
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.
Copies of this mod
8 near-identical copies found in the catalogue:
What it actually says
Invoke the agent-skills:planning-and-task-breakdown skill.
Read the existing spec (SPEC.md or equivalent) and the relevant codebase sections. Then:
- Enter plan mode — read only, no code changes
- Identify the dependency graph between components
- Slice work vertically (one complete path per task, not horizontal layers)
- Write tasks with acceptance criteria and verification steps
- Add checkpoints between phases
- Present the plan for human review
Save the plan to tasks/plan.md and task list to tasks/todo.md.
If tasks/plan.md or tasks/todo.md already exists with unchecked tasks for different work, stop and ask before writing — never silently overwrite an incomplete plan.
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.
- 1mo ago First seen · 19 lines · 13 tokens per session scan A 91d961b2a701
plan is a command published in the GitHub repository addyosmani/agent-skills (110,212 stars, last pushed 11d ago), licensed MIT. It adds 13 tokens to every session and 164 once invoked, about $0.0001 per session on Opus 5.5. 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 commands, from other repositories
ship
A command that runs several specialist checks before software is released, then combines their findings into a decision about whether to launch.
build
A command for carrying out the next unfinished coding task from a plan, including writing tests, implementing the change, checking the project, and committing it. TDD, or test-driven development, means writing a failing test before the code that makes it pass.
constraints
A command for defining a project's quality standards through a short interview and a written CONSTRAINTS.md file. It records checks, thresholds, exceptions, and commands for enforcing them.
code-simplify
A code-review command that simplifies recently changed code or another chosen scope while preserving its behavior.
review
A command that reviews code changes across correctness, readability, architecture, security, and performance.
spec
A command for specification-driven development, where the work is described and agreed in a structured document before coding begins.