The official xai-org/plugin-marketplace repo indexes plugins via .grok-plugin/marketplace.json, with required name and source fields and optional description, category, homepage, keywords, domains, version, author and tags, plus a generated plugin-index.json that must not be edited by hand.

Notesplugins/ holds first-party xAI plugins, external_plugins/ third-party. A plugin may contain skills/, commands/, agents/, hooks/ and server configs. 19 stars; no total plugin count published.

This repo is an index that points at plugin sources so Grok Build can browse, install, and update them.