cmx — Package Manager for Curated Agentic Context
cmx manages the lifecycle of agents and skills for AI coding assistants — versioning, installation, updates, and distribution.
What are agents and skills?
| Artifact | Shape | Purpose |
|---|---|---|
| Agent | Single .md file with YAML frontmatter | Curated guidance for a tech stack — applies across many repositories |
| Skill | Directory with SKILL.md + supporting files | Composable tool capability — task-specific functionality |
What cmx does
- Source management — register git repositories or local directories as artifact sources (plugin marketplaces)
- Install & update — install agents and skills globally or per-project, track versions and checksums
- Status tracking — see what's installed, what's outdated, what's deprecated
- LLM-powered diff — use AI to analyze differences between installed and source versions
- Cross-platform — works with Claude Code, GitHub Copilot, Cursor, Windsurf, and Gemini CLI
Quick example
# Add a source marketplace
cmx source add guidelines https://github.com/svetzal/guidelines
# Search across all sources
cmx search python
# Browse a specific source
cmx source browse guidelines
# Install an agent globally
cmx agent install python-craftsperson
# Install all available agents
cmx agent install --all
# Check what needs updating
cmx outdated
# See an LLM-powered analysis of changes
cmx agent diff rust-craftsperson
# Update everything
cmx agent update --all