Capacium

Capability-native packaging for the AI agent era.

One capability package, any agent framework.

Capacium defines a standard manifest format (capability.yaml), a CLI (cap) for package management, and a trust model based on SHA-256 fingerprinting and Ed25519 signing. Framework adapters bridge the gap between the package format and where capabilities actually run — OpenCode, Claude Code, Gemini CLI, Cursor, and Continue.dev. Includes native MCP (Model Context Protocol) Server support.

Works fully offline from local paths. The Exchange layer (separate repo) adds remote registry discovery with taxonomy, trust states, and crawler-based capability discovery.

Installation

1. Python Global (Recommended)

You can install Capacium globally in an isolated environment using pipx.

pipx install git+https://github.com/Capacium/capacium.git@v1.0.0

# Or with optional signing and YAML support:
pipx install "capacium[yaml,signing] @ git+https://github.com/Capacium/capacium.git@v1.0.0"

Or from PyPI:

pip install capacium

2. Standalone Binaries

If you don't use Python, you can download standalone executables directly from the GitHub Releases page. Extract the archive and place cap in your $PATH.

3. Docker (GHCR)

Run Capacium safely in a container with your directories mounted:

docker run --rm -v ~/.capacium:/root/.capacium -v $(pwd):/workspace ghcr.io/capacium/cap:1.0.0

4. macOS / Linux (Homebrew)

brew install capacium/tap/capacium

Quickstart

# Install a capability
cap install code-reviewer --source ./my-skill

# Create a new capability (interactive)
cap init

# Create a new capability (non-interactive)
cap init --name my-skill --kind skill --version 0.1.0

# Package for distribution
cap package

# Publish to the Exchange registry
cap publish ./dist/my-skill-0.1.0.tar.gz

# List installed capabilities
cap list

# Verify integrity
cap verify --all

# Diagnose missing host runtimes for installed MCP capabilities
cap doctor

# List runtimes Capacium knows about (uv, node, python, docker, …)
cap runtimes list

# Print the install command for a runtime (does NOT execute it)
cap runtimes install uv

# Search the exchange
cap search code-review

# Start the marketplace web UI
cap marketplace

# Generate signing keys
cap key generate mykey

# Sign a capability
cap sign my-skill --key mykey

Publishing Your Skills in 5 Minutes

Got an agent skill, prompt, or MCP server? Publish it on Capacium.

# 1. Create the manifest
cap init
# → name: my-skill
# → kind: skill
# → version: 0.1.0
# → description: Does amazing things

# 2. Package it
cap package
# ✓ Created dist/local-my-skill-0.1.0.tar.gz

# 3. Publish to Exchange
export CAPACIUM_API_TOKEN="cp_..."
cap publish ./dist/local-my-skill-0.1.0.tar.gz
# ✓ Published my-skill v0.1.0

# Users can now install it:
# cap install my-org/my-skill

More in Publishing — CI integration, versioning, signing, and registry setup.

Documentation

Capability Kinds

Features

• Agent-agnostic — Same package works across OpenCode, Claude Code, Gemini CLI, Cursor, Continue.dev
• First-class MCP Support — Deploy and discover MCP servers as native capabilities.
• Eight capability kinds — Skills, bundles, tools, prompts, templates, workflows, mcp-servers, connectors.
• Manifest-first — Standard capability.yaml with metadata, dependencies, and framework targets
• Trust & Governance — SHA-256 fingerprinting and Ed25519 signing for integrity verification.
• Registry-optional — Works fully offline; remote registry adds discovery and distribution.
• Lock files — capability.lock pins exact versions and fingerprints for reproducible installs.
• Zero external deps (core) — Uses only Python stdlib (argparse, sqlite3, hashlib, urllib)

Comparison

License

Apache-2.0. See LICENSE.

Development

Canonical repository: self-hosted Forgejo — git.langevc.com/capacium/capacium (git clone git@git.langevc.com:capacium/capacium.git). Develop against the Forgejo clone and open pull requests there. The GitHub copy is a read-only mirror.