Agent Skills & Open-Source AI
751 resources
Two lists, and they answer different questions. The first three groups are hand-picked: skills, marketplaces and tooling that change how a coding agent works, each with a note on why it is worth knowing about. The rest is every AI repository GitHub returns above ten thousand stars, sorted by what it does - a map of what exists and how much attention it has, not a recommendation. A star count measures interest, not fitness for your problem.
GitHub star counts read 14 September 2026.
anthropics/skills
Anthropic's public repository of Agent Skills
The reference collection, published by Anthropic. Worth reading before writing your own: the skills here are the working examples of the format, so they show what a well-scoped skill looks like and where the boundaries are.
Claude Code Plugins Directory
Anthropic's official directory of Claude Code plugins
Split between plugins Anthropic's team maintains and third-party ones from partners and the community. Install with /plugin install <name>@claude-plugins-official, or browse them under /plugin > Discover. The repo is explicit that Anthropic does not control what a third-party plugin contains and cannot verify it, so check one before installing.
github/spec-kit
A toolkit for spec-driven development with coding agents
GitHub's own take on giving an agent a specification to work from rather than a prompt. The idea is that the spec, not the chat history, is the durable artefact — you refine the spec and regenerate, instead of nudging the agent turn by turn.