Agent Skills by Addy Osmani: 25 engineering habits

What it does

What it is

Addy Osmani works on web performance and engineering practice. He turned his habits into 25 skills that an AI agent can follow, for example how to write a spec, how to review code on five points, and how to run a safe release.

Who it helps

Web developers and builders who let an agent write code. The skills push the agent to slow down at the right moments.

How to start

List the skills, pick two or three, and install them. Ask for a review of your latest change and read the answer.

Be careful

The skills are only instructions. You must still read what the agent changes. Do not install all skills if you only need one habit.

How to install

$ npx skills add addyosmani/agent-skills

$ /plugin marketplace add addyosmani/agent-skills

$ /plugin install agent-skills@addy-agent-skills

How to use it

List the skills first with npx skills add addyosmani/agent-skills --list. Install one, for example code-review-and-quality, and ask the agent to review your change. Or install all 25 as a plugin.

What to watch out for

The skills are text instructions, so the direct risk is low. The agent still runs commands that you approve.
Installing one skill with npx can leave out shared files that other skills use. Install the plugin if a skill asks for a references folder.

Licence and author

Licence: MIT
Author: Addy Osmani
Source code: github.com/addyosmani/agent-skills

How we tested it

We installed it on an empty test computer on 12 Oct 2026. Installed and started in a clean test system. Not yet used in a real AI session.

Test level

We did not run a skill on real code. We did not test the npx install.

Technical details of the test

Date: 12 Oct 2026
Method: Installed the plugin with the Claude Code command line in a clean container with no account. The plugin showed as enabled, and the folder held 25 skills and 5 agent files. All 25 skill files have a name and a description, and the Claude and Codex manifests are valid JSON.

Checked again on 12 Oct 2026

Sources

github.com/addyosmani/agent-skills