@reaatech/a2a-reference-mcp-bridge

Bidirectional A2A ↔ MCP protocol adapter.

A2A → MCP: Call MCP tools from A2A agents

import { McpToolAdapter } from '@reaatech/a2a-reference-mcp-bridge';
 
const adapter = new McpToolAdapter({
  serverUrl: 'http://localhost:3001/sse',
  clientId: 'a2a-agent',
});
await adapter.initialize();
const enrichedCard = adapter.getAgentCard(); // adds MCP tools as skills

MCP → A2A: Expose A2A agent as MCP server

import { A2aAsMcpServer } from '@reaatech/a2a-reference-mcp-bridge';
 
const mcpServer = new A2aAsMcpServer({
  a2aAgentUrl: 'https://agent.example.com',
});
await mcpServer.start({ transport: 'stdio' });

Schema Mapping

MCP Concept	A2A Concept
`tools/list`	`skills` array in Agent Card
Tool input schema	Skill parameters (JSON Schema)
`tools/call` result	Artifact with `parts`
Resource	Artifact with URI addressing
Prompt	Message template
Sampling	`input-required` task state