jacs-cli

CLI and MCP server for JACS — cryptographic identity, signing, and verification for AI agents.

cargo install jacs-cli

Or via Homebrew:

brew tap HumanAssisted/homebrew-jacs
brew install jacs

This installs the jacs binary with CLI and MCP server built in.

Quick start

export JACS_PRIVATE_KEY_PASSWORD='your-password'

jacs quickstart --name my-agent --domain example.com
jacs document create -f mydata.json
jacs verify signed-document.json

MCP server

jacs mcp

The MCP server uses stdio transport only — no HTTP endpoints. This is deliberate: the server holds the agent's private key, so it runs as a subprocess of your MCP client. No ports are opened.

Configure in your MCP client (Claude Desktop, Cursor, Claude Code, etc.):

{
  "mcpServers": {
    "jacs": {
      "command": "jacs",
      "args": ["mcp"]
    }
  }
}

For headless/server environments:

export JACS_CONFIG=/srv/my-project/jacs.config.json
export JACS_PASSWORD_FILE=/run/secrets/jacs-password
export JACS_KEYCHAIN_BACKEND=disabled
jacs mcp

Links

• Full Documentation
• Quick Start Guide
• CLI Command Reference
• MCP Integration
• JACS on crates.io

v0.9.7 | Apache 2.0 with Common Clause