Interface App<T>

ReadonlyclientTypes

// server.ts
export { app };

// ui.tsx
import { createTypedClient } from "@mcp-apps-kit/ui";
import { app } from "./server";
const client = await createTypedClient(app);
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// server.ts
export const v1 = app.getVersion("v1")!;

// ui.tsx
const client = await createTypedClient(v1);
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ReadonlyexpressApp

// For Vercel deployment, export the Express app:
export default app.expressApp;
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Readonlytools

getServer

• getServer(): McpServer

  Get the underlying MCP server instance

  Returns McpServer

getVersion

• getVersion(versionKey: string): App<T>

  Get a version-specific app instance

  For multi-version apps, returns the app instance for the specified version. For single-version apps, returns undefined.

  Parameters

  • versionKey: string

    Version key (e.g., "v1", "v2")

  Returns App<T>

  App instance for the version, or undefined if not found

  Example

  const v1App = app.getVersion("v1");
  if (v1App) {
    v1App.use(v1SpecificMiddleware);
  }
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getVersions

• getVersions(): string[]

  Get list of available version keys

  For multi-version apps, returns array of version keys (e.g., ["v1", "v2"]). For single-version apps, returns empty array.

  Returns string[]

  Array of version keys

  Example

  const versions = app.getVersions();
  // ["v1", "v2"] for multi-version apps
  // [] for single-version apps
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handler

• handler(): ExpressMiddleware

  Get Express middleware for custom server setup

  Returns ExpressMiddleware

handleRequest

• handleRequest(req: Request, env?: unknown): Promise<Response>

  Handle a single request (for serverless)

  Parameters

  • req: Request
  • Optionalenv: unknown

  Returns Promise<Response>

on

• on<K extends keyof EventMap>(
      event: K,
      handler: EventHandler<EventMap[K]>,
  ): UnsubscribeFn

  Subscribe to event

  Handler called every time event is emitted until unsubscribed. Handlers execute in registration order. Errors in handlers are isolated (logged but don't affect other handlers).

  Type Parameters

  • K extends keyof EventMap

  Parameters

  • event: K

    Event name (type-checked)

  • handler: EventHandler<EventMap[K]>

    Handler function (payload type inferred)

  Returns UnsubscribeFn

  Unsubscribe function

onAny

• onAny(handler: AnyEventHandler): UnsubscribeFn

  Subscribe to all events (wildcard listener)

  Handler receives every event with event name and payload. Useful for logging, debugging, or analytics.

  Parameters

  • handler: AnyEventHandler

    Handler function receiving all events

  Returns UnsubscribeFn

  Unsubscribe function

once

• once<K extends keyof EventMap>(
      event: K,
      handler: EventHandler<EventMap[K]>,
  ): UnsubscribeFn

  Subscribe to event (one-time)

  Handler called once, then automatically unsubscribed. Useful for initialization events or one-time setup.

  Type Parameters

  • K extends keyof EventMap

  Parameters

  • event: K

    Event name (type-checked)

  • handler: EventHandler<EventMap[K]>

    Handler function (payload type inferred)

  Returns UnsubscribeFn

  Unsubscribe function (can call to cancel before event fires)

start

• start(options?: StartOptions): Promise<void>

  Start the built-in Express server

  Parameters

  • Optionaloptions: StartOptions

  Returns Promise<void>

use

• use(middleware: Middleware): void

  Register middleware function

  Middleware executes in registration order before tool handlers. Multiple middleware can be registered via multiple use() calls.

  Parameters

  • middleware: Middleware

    Middleware function

  Returns void

  Example

  app.use(loggingMiddleware);
  app.use(authMiddleware);
  app.use(rateLimitMiddleware);
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