A2A MCP

@cognicellai/a2a-mcp is an MCP server that bridges local MCP hosts to A2A v1-compatible agents.

It exposes the A2A v1 client operation surface through MCP tools and routes A2A calls through the official @a2a-js/sdk client.

Install From npm

Install it from the official npm registry:

npm install -g @cognicellai/a2a-mcp

Or run it directly with npx:

A2A_MCP_CONFIG=/absolute/path/to/a2a-mcp.config.yaml npx -y @cognicellai/a2a-mcp

For MCP host setup, see docs/host-setup.md. For end-to-end usage examples covering no-auth, API-key, and machine-to-machine OAuth A2A agents, see docs/user-guide.md.

The installed CLI command is a2a-mcp.

For maintainers preparing a release, see docs/release.md.

Related MCP server: Agent Aggregator

Development From Source

npm install
npm run build
npm test
npm run typecheck
npm run lint:docs

Start the MCP server over stdio:

A2A_MCP_CONFIG=./a2a-mcp.config.example.yaml npm run dev

Configuration

Agents are configured by alias. Credentials are referenced by profile and resolved from the local environment; token values are never accepted as MCP tool arguments.

See a2a-mcp.config.example.yaml.

Agent Card signature handling is fail-closed by default: unsigned cards are accepted with signaturePolicy: "ifPresent", but signed cards are rejected until trust-root-backed signature verification is implemented. Use signaturePolicy: "disabled" only for explicitly trusted local or development agents.