capacium 0.16.0

Capability Packaging System — agent-agnostic packaging for AI agent capabilities

Capacium

[!NOTE] Public mirror. The canonical repository is hosted on our self-hosted git. This GitHub copy is a read-only mirror kept in sync for visibility and installation. Bug reports are welcome via Issues; pull requests are applied upstream and synced back here.

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@v0.16.0

# Or with optional signing and YAML support:
pipx install "capacium[yaml,signing] @ git+https://github.com/Capacium/capacium.git@v0.16.0"

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:0.16.0

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

Guide	Description
Getting Started	Installation, quickstart, examples
CLI Reference	Complete command reference
Manifest Format	capability.yaml reference
Signing & Keys	Ed25519 signing and verification
Marketplace	Web UI and registry server
Bundle Support	Multi-capability bundles
Lock Files	Dependency pinning
Framework Adapters	Cross-framework installation
Runtimes	Host runtime resolver, cap doctor, cap runtimes
Publishing	Full lifecycle: dev → CI → Exchange publish
Registry	Local and remote registry
API Spec	Remote registry protocol

Capability Kinds

Kind	Description	Example
skill	Agent skill/prompt	Code review, doc generator
bundle	Collection of sub-capabilities	Dev toolkit, skill suite
tool	Function/tool definition	Web search, calculator
prompt	Reusable prompt template	System prompts, instructions
template	Project/code template	Skill scaffold, adapter template
workflow	Multi-step agent workflow	CI pipeline, data chain
mcp-server	MCP Server	MCP filesystem, db-connector
connector-pack	Tool/Service integration	Slack, GitHub, Jira connector pack

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

Capability	Direct copy/script	Framework-specific	Capacium
Cross-framework format	No	No	Yes
Manifest standard	No	Partial	Yes
Fingerprint verification	No	No	Yes
Cryptographic signing	No	No	Yes
Dependency resolution	Manual	No	Yes
Offline operation	Yes	Partial	Yes
Registry discovery	No	Vendor lock-in	Optional

License

Apache-2.0. See LICENSE.

Development

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