OPEN SOURCE · AGENT SKILLS · MIT
Agent Skills Marketplace
An open-source marketplace of portable agent skills and plugins maintained by the Institute. Skills are written to the open SKILL.md convention, so the same plugin installs into Claude Code and Copilot CLI without being rewritten for either.
01 — SKILLS AS PORTABLE CAPABILITY
Skills as portable capability
A skill is a folder with a SKILL.md at its root: a short description the agent matches against the task in front of it, and the procedure it should follow once it does. Because the format is a convention rather than a vendor feature, a skill written once is not tied to the assistant it was written in. The marketplace packages skills into plugins, and a plugin is the unit an assistant installs.
The value is in what that portability protects. Capability captured as a skill outlives the tool it was captured in, stays reviewable as ordinary text in version control, and can be corrected in public when it turns out to be wrong. That is the same argument the Institute makes for the rest of its open-source work, applied to the instructions we hand to agents.
02 — INSTALLING FROM EITHER CLIENT
Installing from either client
The marketplace is registered once, then plugins are installed from it by name. Claude Code takes the slash-command form and Copilot CLI the shell form; both read the same catalogue from the same repository. Replace dev-utilities with whichever plugin you want, or point your assistant at the repository's INSTALL.md, which checks prerequisites and does the registration and installation for you.
/plugin marketplace add EthicalML/agent-skills-marketplace/plugin install dev-utilities@agent-skills-marketplacecopilot plugin marketplace add EthicalML/agent-skills-marketplacecopilot plugin install dev-utilities@agent-skills-marketplace03 — THREE PLUGINS IN THE CATALOGUE
Three plugins in the catalogue
Five skills ship across three plugins today, each one a working tool rather than a demonstration. They cover the three jobs that came up often enough in the Institute's own work to be worth writing down properly.
Writing and explaining code: author reliable skills, walk through a commit or pull request, and align agent instruction files across tools.
Read morePLUGIN · 1 SKILLsite-captureRecording website walkthroughs: a scripted screen capture of a site as video or GIF, with human-paced scrolling and a visible cursor.
Read morePLUGIN · 1 SKILLagent-harnessBuilding Python agents: a skill-driven harness with deferred capability loading, custom tools and any OpenAI-compatible model endpoint.
Read more04 — CONTRIBUTING A SKILL
Contributing a skill
Contributions arrive as pull requests. Every change runs through scripts/validate.sh, which checks plugin and skill structure before a reviewer sees it, so a submission either satisfies the format or says why it does not. CONTRIBUTING.md in the repository is the reference for what a good skill looks like and what the validator expects.