Claude Code Skills on GitHub

Start with the official repository

github.com/anthropics/skills is Anthropic's own reference skills repo — 17 skills including the document family (docx, pdf, pptx, xlsx), skill-creator, mcp-builder, webapp-testing, and frontend-design. Worth knowing before you install any of these: the document skills are Proprietary-licensed (LICENSE.txt has the terms), and most of the rest say only "complete terms in LICENSE.txt" — none of this is MIT, unlike a lot of what shows up further down this page.

Official plugin marketplaces

Plugins can bundle skills with agents, hooks, and MCP servers. Anthropic runs three catalogs, with real differences in how much vetting each one implies:

Marketplace	What it is	Added
`claude-plugins-official`	Curated directly by Anthropic	Automatically, on first interactive launch
`claude-plugins-community` (anthropics/claude-plugins-community)	Third-party plugins that passed automated validation + safety screening, pinned to a commit SHA	`/plugin marketplace add anthropics/claude-plugins-community`
`claude-code-plugins` (in anthropics/claude-code`/plugins`)	Demo/example plugins, not vetted for production use	`/plugin marketplace add anthropics/claude-code`

Full install commands: how to install Claude Code skills.

Real vendor and community skill sources

Source	What it actually is
`obra/superpowers`	A large, independently popular software-development-methodology skill framework — brainstorming, planning, TDD, debugging. MIT-licensed. This is the same framework Nous Research separately adapted for Hermes Agent's own bundled skills.
`trailofbits/skills`	Trail of Bits — a well-known security research firm — publishing their own skills for security research, vulnerability detection, and audit workflows. CC-BY-SA-4.0.
`NVIDIA/skills`	NVIDIA's own skills for Physical AI, robotics, simulation, CUDA, and RAG workflows, explicitly built to work in Claude Code and Codex both. Apache-2.0.
`vercel-labs/skills`	Not a skill catalog — the `npx skills` installer tool itself (see how to install). MIT-licensed, cross-agent.

Beyond these, there's a long tail of "awesome-claude-code-skills"-style community registries — several exist, each claiming its own curated count. Treat those claims as the repo's own marketing, the same way you'd treat a "70+ verified skills" claim anywhere else: real, but self-reported, not independently audited.

How to evaluate a skill before installing it

Claude Code has no automated scanner for a hand-written or npx skills-installed skill — see is a skill checked for anything before it runs? That makes this checklist do more work here than on ecosystems with an install-time security gate.

1. Does the description actually match what you'd say? Claude matches your request against it. A vague or overly broad description means the skill fires on requests it shouldn't, or never fires at all.

2. What's in allowed-tools? This is the field that matters most for risk. It pre-approves tools for the entire turn that invokes the skill without asking you — including Bash commands matching a pattern. A skill granting itself broad Bash(*) access is a real thing to notice, not a formality.

3. Does it use context: fork? A forked skill runs as a background subagent with its own tool access and no view of your conversation history. Check what agent it specifies and what that agent type can do before trusting a forked skill with anything sensitive.

4. What do the !-injected commands do? Anything on a line starting with !`command` runs before Claude ever sees the skill content. Read every injected command the same way you'd read a postinstall script — it runs unconditionally, with no confirmation prompt, the moment the skill loads.

5. Is it a plugin or a standalone skill? A plugin from the community marketplace passed automated validation and safety screening; a standalone SKILL.md you copied from a repo passed through nothing. Know which one you're installing.

6. License and last commit. Same as anywhere else: check there is one, and that push recency (not stars) is your real signal for whether something is still maintained.

Sources

anthropics/skills (GitHub)
Claude Code — Discover and install plugins (official docs)
Claude Code — Skills (official docs)
Live GitHub repository search conducted August 2026 for Claude-Code-skill-related repositories