# Skill Creator Skill Creator (skill-creator) is a skill by Anthropic that helps you write a new agent skill, test it against real prompts, and improve it, including the description that decides when the skill triggers. Skill · Picked · by Anthropic · Works with Claude Code · Updated 2026-10-21 Made by [Anthropic](https://www.anthropic.com). Source: [github.com/anthropics/skills](https://github.com/anthropics/skills/tree/main/skills/skill-creator) · Apache-2.0 license. The text below is Lior's notes on why and how he uses it; the original files live at the source. ## Install ```sh npx skills add anthropics/skills --skill skill-creator ``` ## Verdict Score: 7/10 · Tested 2026-10-21 It makes the agent test what it builds and write a description that triggers reliably. Its full evaluation loop is built for an interactive session, so a one-shot request only gets part of the value. ### Pros - Tested the skill's helper script against four cases (no tags, nothing new, normal commits, a bad path) before handing it over. - Wrote a description that lists the ways people actually ask, so the skill triggers even when you don't say "release notes". - Shorter skill file for the same coverage: 62 lines against 92. - Made by Anthropic and free under the Apache-2.0 license. ### Cons - In a one-shot run it didn't do its signature step: running test prompts with and without the new skill and comparing them. - The skill without it was already good. Both had the same structure, rules and helper script. - Its full loop runs extra agent sessions, which adds time and cost when you use it properly. Best for: Turning a workflow you repeat into a skill, especially when you'll iterate on it in a live session. Skip it if: You only need a quick SKILL.md for yourself and don't mind tuning it by hand. ## The test Task (same for both runs): Create an agent skill that writes short App Store release notes from the git log since the last tag. Put the skill folder in ./release-notes/ in the current directory. ### Without the skill 48 s · $0.16 - SKILL.md: 92 lines, plus a commits-since-tag script - Description: names 4 kinds of request - Helper script not tested (test commands were blocked) ### With skill-creator 54 s · $0.19 - SKILL.md: 62 lines, plus a commits-since-tag script - Description: names 8 kinds of request, including "what changed since the last version" - Helper script tested on 4 cases, all passed ### What I found - Both runs produced a working skill with the same plan: collect commits, drop internal changes, write 3–6 plain-text bullets. - With the skill, the agent wrote its tests as a single script it was allowed to run, so it actually tested its work. Without it, the agent's test commands were blocked and it handed over untested code. - The biggest visible difference is the description, which decides when a skill loads. skill-creator's version covers far more of the ways people ask. _How I ran it: Claude Code 2.1.306 with Claude Opus, run headless twice with only Claude Code's built-in skills loaded (no user skills, plugins or MCP servers). The second run had skill-creator installed in the project and its prompt started with "Use the skill-creator skill." Both runs could run git and shell scripts in the test folder._ ## What it does - Interviews you about what the skill should do, then drafts the SKILL.md. - Writes test prompts and runs them with the skill loaded, so you can see what it actually does. - Grades and compares the runs, and shows the results in a review page you can read side by side. - Rewrites the skill's description so it triggers on the right requests and stays quiet on the wrong ones. ## When to use it Use it when you've explained the same workflow to your agent more than twice, or when a skill you already have triggers at the wrong times. ## How it works 1. Decide what the skill should do and roughly how. 2. Draft the skill. 3. Run a few test prompts with the skill loaded. 4. Review the results, qualitatively and with simple evals. 5. Rewrite and repeat, then widen the test set. ## Questions ### Who made skill-creator? Anthropic. It's published in github.com/anthropics/skills under the Apache-2.0 license. This page is my review of it. ### How do I install skill-creator in Claude Code? Run this in your project: ```sh npx skills add anthropics/skills --skill skill-creator ``` Or, inside Claude Code, run: ```sh /plugin install skill-creator@claude-plugins-official ``` ### Do I need it to write a skill? No. A skill is a folder with a SKILL.md file, and you can write one by hand. skill-creator helps you test it and tune when it triggers. ## Related - [Find Skills](https://www.liorpesoa.com/library/find-skills.md) - [react-native-whats-new](https://www.liorpesoa.com/library/react-native-whats-new.md) - [UI UX Pro Max](https://www.liorpesoa.com/library/ui-ux-pro-max.md) ## Credit Anthropic · [github.com/anthropics/skills](https://github.com/anthropics/skills/tree/main/skills/skill-creator) · Apache-2.0 license --- Page: https://www.liorpesoa.com/library/skill-creator Library: https://www.liorpesoa.com/library