gRPC MCP Server

Instructions

Implementation Reference

• src/index.ts:44-59 (registration)

  Registration of the MCP tool 'loadProto', including inline input schema and handler function that calls loader.loadAsync on the provided directory and serializes the result to JSON string.

  server.addTool({
      name: "loadProto",
      description: "Load a proto file and return its content",
      parameters: z.object({
          dir: z.string().describe("Directory containing the proto file (e.g., /path/to/proto)"),
      }),
      execute: async (args) => {
          try {
              const res = await loader.loadAsync(args.dir);
              return obj2String(res, true);
          } catch (e) {
              Logger.error(e);
              return e instanceof Error ? e.message : "An unknown error occurred";
          }
      },
  });

• src/loader.ts:27-44 (handler)

  Core implementation logic for loading and parsing proto files from a directory: fetches proto definitions, extracts service names and method lists, structures output as array of objects with path and services.

  async loadAsync(dir: string): Promise<Proto[]> {
      const proto = await protoLoader.loadAsync(dir);
      const result: Proto[] = [];
      for (const p of proto) {
          const services: Service[] = [];
          for (const s of p.protocolBuffer.services) {
              services.push({
                  name: s.name,
                  methods: s.methods.map(m => m.name),
              });
          }
          result.push({
              path: p.protocolBuffer.metadata.protoPath,
              services: services,
          });
      }
      return result;
  },

• src/Grpc/ProtocolBuffer/ProtoLoader.ts:93-97 (helper)

  Helper function protoLoader.loadAsync that discovers all .proto files in the directory, loads each asynchronously using loadProtoAsync (which uses @grpc/proto-loader), and returns array of parsed package definitions used by the loader.

  async loadAsync(fileOrDir: string): Promise<ProtocolBufferPackageDefinition[]> {
      const files = await getFileAsync(fileOrDir, { extensions: [proto_ext] });
      const protoTask = files.map((file) => this.loadProtoAsync(file));
      return Promise.all(protoTask);
  }