Manual Usage

Inject the OpenAPIMcpService for programmatic MCP server usage (e.g., dedicated stdio process, custom transport handling, or advanced lifecycle control).

Inject the service

import { Inject, Injectable } from "@nestjs/common";
import { OpenAPIMcpService, OPENAPI_MCP } from "@nest-openapi/mcp";

@Injectable()
export class McpRunnerService {
  constructor(@Inject(OPENAPI_MCP) private readonly mcp: OpenAPIMcpService) {}
}

Start stdio transport manually

Use this for CLI agents or sidecar MCP processes:

await this.mcp.startStdio();

This creates the MCP server from your OpenAPI spec and connects it to stdio transport.

Create and extend server programmatically

You can create a fully configured MCP server instance and manage transport yourself:

const server = await this.mcp.createServer();
// connect your own transport here

For non-manual patterns such as extendServer, HTTP session strategy, and header-forwarding policy, see Advanced setup.