Agent skill · Anthropic

Skill Creator skill for Claude Code, Codex and Cursor

Helps write new skills, refine existing ones and test how well they trigger and perform.

Officialname: skill-creator★ 184k (repo)pushed 2026-10-09Apache-2.0SKILL.md on GitHubchecked 2026-11-07

What it does, in the publisher's words

Create new skills, modify and improve existing skills, and measure skill performance. Use when users want to create a skill from scratch, edit, or optimize an existing skill, run evals to test a skill, benchmark skill performance with variance analysis, or optimize a skill's description for better triggering accuracy.

The description field of the SKILL.md. The agent reads only this at startup and decides from it when to load the full skill.

Install Skill Creator

The skills CLI copies the skill into the folder of each agent you pick (Claude Code, Codex, Cursor, Copilot, Gemini CLI, OpenCode, Windsurf...). Add -g for all projects. Needs Node.js 22.20+. docs

npx skills add anthropics/skills --skill skill-creator

This repo is a plugin marketplace. Inside Claude Code, add it and install the plugin that holds the skill (document-skills, example-skills, claude-api, academy-guide...), or copy only this skill into ~/.claude/skills. docs

/plugin marketplace add anthropics/skills
/plugin install <plugin>@anthropic-agent-skills

# or only this skill:
npx skills add anthropics/skills --skill skill-creator -a claude-code

Download the skill folder, zip it, then Customize > Skills > + > Create skill > Upload a skill. Code execution must be on (Settings > Capabilities). docs

git clone --depth 1 https://github.com/anthropics/skills.git /tmp/skill-creator-src
cp -r /tmp/skill-creator-src/skills/skill-creator ./skill-creator
zip -r skill-creator.zip skill-creator

Codex reads skills from .agents/skills in the repo or ~/.agents/skills. Type $ in Codex to use one. docs

npx skills add anthropics/skills --skill skill-creator -a codex

gh skill (GitHub CLI 2.90+, preview) installs it for Copilot in VS Code, the CLI and the cloud agent. Copilot also reads .github/skills and ~/.copilot/skills. docs

gh skill install anthropics/skills skill-creator

Cursor reads .cursor/skills, .agents/skills and ~/.cursor/skills (and .claude/skills). It does not install loose skills from a GitHub URL, so copy it in. docs

npx skills add anthropics/skills --skill skill-creator -a cursor

Installs from the GitHub repo; --path picks this skill out of the repo. Default scope is user (all projects). docs

gemini skills install https://github.com/anthropics/skills.git --path skills/skill-creator

OpenCode reads .opencode/skills, ~/.config/opencode/skills and the Claude and .agents folders. docs

npx skills add anthropics/skills --skill skill-creator -a opencode

Windsurf (now Devin Desktop) reads .devin/skills, .windsurf/skills and ~/.codeium/windsurf/skills. docs

npx skills add anthropics/skills --skill skill-creator -a windsurf

Works with

Claude Code, Claude.ai and Claude Desktop, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and other agents that read the open Agent Skills format.

Bundles 10 Python scripts the agent can run, so it needs Python on the machine. In the Claude apps, code execution must be on.

What's in the SKILL.md

29 sections

Communicating with the user
Creating a skill
Capture Intent
Interview and Research
Write the SKILL.md
Skill Writing Guide
Writing Style
Test Cases
Running and evaluating test cases
Step 1: Spawn all runs (with-skill AND baseline) in the same turn
Step 2: While runs are in progress, draft assertions
Step 3: As runs complete, capture timing data
Step 4: Grade, aggregate, and launch the viewer
What the user sees in the viewer
Step 5: Read the feedback
Improving the skill
How to think about improvements
The iteration loop
Advanced: Blind comparison
Description Optimization
Step 1: Generate trigger eval queries
Step 2: Review with user
Step 3: Run the optimization loop
How skill triggering works
+ 5 more

Bundled files

LICENSE.txt
agents/analyzer.md
agents/comparator.md
agents/grader.md
assets/eval_review.html
eval-viewer/generate_review.py
eval-viewer/viewer.html
references/schemas.md
scripts/__init__.py
scripts/aggregate_benchmark.py
scripts/generate_report.py
scripts/improve_description.py
scripts/package_skill.py
scripts/quick_validate.py
scripts/run_eval.py
scripts/run_loop.py
scripts/utils.py

Loaded only when the instructions point to them.

Facts

Skill name: skill-creator
Publisher: Anthropic (official)
Repo: anthropics/skills
License: Apache-2.0
SKILL.md size: 4,848 words, 481 lines
Bundled files: 17, 10 scripts (Python), 4 docs
Repo stars: 184k (as of 2026-10-24)
SKILL.md checked: 2026-11-07

More skills from anthropics/skills

Canvas Design: Produces posters and static artwork as PNG or PDF files, guided by a written design philosophy.
Claude API: Reference for building on the Claude API and Anthropic SDKs: models, tool use, streaming, caching, pricing.
Doc Co-authoring: Walks you through drafting specs, proposals and design docs step by step with Claude.
Word Documents (DOCX): Creates, reads and edits Word .docx files, including templates, tracked changes and formatting.
Frontend Design: Steers UI work toward deliberate visual direction and typography instead of generic template looks.
MCP Server Builder: Guide for designing and building Model Context Protocol servers that wrap external APIs as tools.
PDF: Extracts text and tables, merges, splits, fills forms and creates PDF files.
PowerPoint (PPTX): Builds, reads and edits PowerPoint decks and templates, including layouts and speaker notes.
Slack GIF Creator: Makes small animated GIFs sized and validated for Slack's emoji and message limits.
Web Artifacts Builder: Builds multi-component HTML artifacts with React, Tailwind and shadcn/ui, bundled into one file.
Web App Testing: Uses Playwright to drive a local web app, check behavior, read console logs and take screenshots.
Excel Spreadsheets (XLSX): Opens, cleans, edits and creates spreadsheets (.xlsx, .csv), including formulas and charts.

Related workflow & planning skills

GitHub: Address PR Comments · OpenAI
Skill Installer (Codex) · OpenAI
Modern Python Tooling · Trail of Bits
Commit (Sentry style) · Sentry
Notion Spec to Implementation · Notion
Brainstorming · Jesse Vincent (obra)
Requesting Code Review · Jesse Vincent (obra)
Subagent-Driven Development · Jesse Vincent (obra)

FAQ

What does the skill-creator skill do?+

Helps write new skills, refine existing ones and test how well they trigger and perform. In its own SKILL.md, Anthropic describes it as: "Create new skills, modify and improve existing skills, and measure skill performance. Use when users want to create a skill from scratch, edit, or optimize an existing skill, run evals to test a skill, benchmark skill performance with variance analysis, or optimize a skill's description for better..."

How do I install the skill-creator skill?+

Run npx skills add anthropics/skills --skill skill-creator and pick your agents, or use the tab for your agent above. In Claude Code the skill ends up in ~/.claude/skills/skill-creator/SKILL.md; in Codex and Cursor in .agents/skills/skill-creator/.

Does Skill Creator work in Codex, Cursor and Copilot, or only Claude?+

It's a standard SKILL.md, so any agent that reads the Agent Skills format can use it: Claude Code, the Claude apps, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and more.

Who maintains Skill Creator?+

Anthropic, the company or project behind it, in the anthropics/skills repo on GitHub, last pushed 2026-10-09. License: Apache-2.0.

Read a skill's SKILL.md and scripts before you install it: skills aren't verified by any agent vendor. Claude skills marketplace · How to install skills · MCP servers