Start with MCP

Verify another agent's output, sign an audit record, preserve an agreement transcript, or verify text and images. Start with the use cases to choose the appropriate MCP profile, then connect your client.

JACS signs structured data and verifies it using explicit public evidence. MCP is the primary integration. Install the portable CLI and start its stdio server:

cargo install jacs-cli --locked
jacs mcp

The default profile exposes jacs_verify_document. Verification checks integrity under the supplied public key; identity, consent, trust and permission remain application decisions. Diagnostics go to stderr and stdout carries only MCP.

Explicit local signing provides create, sign, verify, rotate, re-encrypt and encrypted import/export operations for one selected vault. New identities use pq2025 (ML-DSA-87), without automatic classical fallback. Passwords belong in the host's prompt or designated environment variable, never in MCP parameters.

See the complete MCP contract and configuration guide and CLI commands. The extended MCP profiles provide separate agreement and media capabilities for existing integrations.

Rust, Node.js, Python and Go remain supported direct libraries, alongside browser and mobile bindings. See supported packages or choose your language in the navigation. Native APIs include capabilities beyond the portable MCP tool set; they remain in their own dependency workspace.