How to install an agent skill in Claude Code, Codex, Cursor and more

One command covers most coding agents; this is where each tool looks for skills, and how to check one actually loaded.

Onei AI Editorial October 30, 2026 4 min read How we make this

Updated October 30, 2026.

An agent skill is a folder that teaches a coding agent one job. Installing one takes a minute once you know where your agent looks for it. This guide covers the one command that works for most agents, the folders each major tool reads, and how to check that the skill actually loaded.

What you are installing

A skill is a directory with a SKILL.md file at its root. The file opens with YAML frontmatter holding two required fields, then plain Markdown instructions:

---
name: frontend-design
description: What the skill does and when the agent should use it.
---

Step-by-step instructions for the agent…

Under the open Agent Skills specification, name is up to 64 lowercase letters, digits and hyphens and must match the folder's name; description is up to 1,024 characters. The folder may also carry scripts/, references/ and assets/.

Skills load progressively, which is why you can install dozens without filling the context window. At startup the agent reads only each skill's name and description, about 100 tokens apiece. The full instructions load when a task matches the description, and bundled files only when the instructions call for them. That also means the description is the trigger: a skill with a vague description rarely fires on its own.

The quick way: one command for most agents

The skills CLI from Vercel Labs installs from any Git repository into whichever agents you have. It needs Node.js 22.20 or later; run it from your project:

npx skills add anthropics/skills --skill frontend-design

It detects the agents on your machine and asks where to install. The flags worth knowing:

--skill <name> picks one skill from a repository that holds many; --list shows what a repository contains without installing anything.
-a <agent> targets an agent directly, for example -a claude-code or -a codex.
-g installs for your user account instead of the current project.
npx skills list, npx skills update and npx skills remove manage what you have.

Project installs go into the repository, so committing them shares the skill with everyone who works on it. Every skill page on Onei leads with this command, already filled in: see geo-sleuth or Playwright CLI.

Installing by hand

A skill is just a folder, so you can also copy it (or git clone it) into the right directory. The folder name should match the name in its frontmatter.

Claude Code: .claude/skills/<name>/ in a project, ~/.claude/skills/<name>/ for you.
OpenAI Codex: .agents/skills/<name>/ in a project, ~/.agents/skills/<name>/ for you.
Cursor: .cursor/skills/ or .agents/skills/ in a project, ~/.cursor/skills/ or ~/.agents/skills/ for you.
GitHub Copilot in VS Code: .github/skills/ in a project, ~/.copilot/skills/ for you.

The folders overlap more than the table suggests. Cursor also reads .claude/skills/ and .codex/skills/ (and their home-directory versions), and local Copilot sessions in VS Code also read .claude/skills/ and .agents/skills/. A skill installed for Claude Code is often already visible to your other tools.

Some skills ship as plugins instead. In Claude Code a plugin is added from a marketplace with /plugin marketplace add <owner/repo> and then /plugin install; Anidoodle is installed that way, and its page lists the exact commands.

Claude apps: upload a ZIP

On claude.ai and the Claude desktop app, skills are available on the Free, Pro, Max, Team and Enterprise plans and need code execution switched on (Settings → Capabilities). To add your own, zip the skill folder, go to Customize → Skills, choose "+", then "Create skill" and "Upload a skill". Uploads most often fail because the folder name does not match the skill name or SKILL.md is missing.

Check that it loaded

Claude Code: run /skills to list what loaded, or call one directly with /skill-name. New and edited skills are picked up without a restart; if you created the top-level skills folder during the session, run /reload-skills.
Codex: type $ or run /skills to pick a skill explicitly. Codex detects changes on its own; restart it if a skill does not appear. Its built-in $skill-installer can also fetch curated skills for you.
Cursor and VS Code: type / in the agent chat and search for the skill's name.

If a skill loads but never fires on its own, read its description: the agent matches your request against it, so call the skill by name or rephrase your request in the description's terms.

Before you install

A skill is instructions plus, often, scripts your agent will run on your machine. Read SKILL.md and anything in scripts/ before installing a skill from someone you do not know, the same way you would read a shell script before piping it to bash. Prefer project installs for anything experimental, so a skill's reach ends at one repository.

Where to find skills

Onei lists hundreds of agent skills, each with its source, licence and install command, plus skills for development and for design and creative work. Good first installs: Anthropic's frontend-design and skill-creator, which helps you write a skill of your own, and Microsoft's Playwright CLI for driving a browser.