Function createApp

createApp<T extends ToolDefs>(config: AppConfigInput<T>): App<T>

Create an MCP app with unified tool and UI definitions

Supports both single-version (backward compatible) and multi-version configurations.

Type Parameters

T extends ToolDefs

Parameters

config: AppConfigInput<T>
App configuration with tools and UI resources

Returns App<T>

App instance for starting server or getting middleware

Example: Single-version (backward compatible)

const app = createApp({
  name: "my-app",
  version: "1.0.0",
  tools: {
    greet: {
      description: "Greet a user",
      input: z.object({ name: z.string() }),
      output: z.object({ message: z.string() }),
      handler: async ({ name }) => ({ message: `Hello, ${name}!` }),
    },
  },
});

await app.start({ port: 3000 });

Example: Multi-version

const app = createApp({
  name: "my-app",
  config: {
    oauth: { authorizationServer: "https://auth.example.com" },
    cors: { origin: true }
  },
  versions: {
    v1: {
      version: "1.0.0",
      tools: { greet: {...} }
    },
    v2: {
      version: "2.0.0",
      tools: { greet: {...}, search: {...} }
    }
  }
});