lib: add capabilities & version getters (modelcontextprotocol#24)

* add App{,Bridge}.get{App,Host}{Version,Capabilities}()

* Add App.{oncalltool,onlisttools}

Author: ochafik

src/app-bridge.ts

@@ -63,12 +63,13 @@ type HostOptions = ProtocolOptions;
 
 export const SUPPORTED_PROTOCOL_VERSIONS = [LATEST_PROTOCOL_VERSION];
 
-type RequestExtra = Parameters<
+type RequestHandlerExtra = Parameters<
   Parameters<AppBridge["setRequestHandler"]>[1]
 >[1];
 
 export class AppBridge extends Protocol<Request, Notification, Result> {
   private _appCapabilities?: McpUiAppCapabilities;
+  private _appInfo?: Implementation;
 
   constructor(
     private _client: Client,
@@ -88,7 +89,14 @@ export class AppBridge extends Protocol<Request, Notification, Result> {
     });
   }
 
-  onping?: (params: PingRequest["params"], extra: RequestExtra) => void;
+  getAppCapabilities(): McpUiAppCapabilities | undefined {
+    return this._appCapabilities;
+  }
+  getAppVersion(): Implementation | undefined {
+    return this._appInfo;
+  }
+
+  onping?: (params: PingRequest["params"], extra: RequestHandlerExtra) => void;
 
   set onsizechange(
     callback: (params: McpUiSizeChangeNotification["params"]) => void,
@@ -114,7 +122,7 @@ export class AppBridge extends Protocol<Request, Notification, Result> {
   set onmessage(
     callback: (
       params: McpUiMessageRequest["params"],
-      extra: RequestExtra,
+      extra: RequestHandlerExtra,
     ) => Promise<McpUiMessageResult>,
   ) {
     this.setRequestHandler(
@@ -127,7 +135,7 @@ export class AppBridge extends Protocol<Request, Notification, Result> {
   set onopenlink(
     callback: (
       params: McpUiOpenLinkRequest["params"],
-      extra: RequestExtra,
+      extra: RequestHandlerExtra,
     ) => Promise<McpUiOpenLinkResult>,
   ) {
     this.setRequestHandler(
@@ -168,6 +176,7 @@ export class AppBridge extends Protocol<Request, Notification, Result> {
     const requestedVersion = request.params.protocolVersion;
 
     this._appCapabilities = request.params.appCapabilities;
+    this._appInfo = request.params.appInfo;
 
     const protocolVersion = SUPPORTED_PROTOCOL_VERSIONS.includes(
       requestedVersion,

src/app.ts

@@ -6,9 +6,12 @@ import {
 
 import {
   CallToolRequest,
+  CallToolRequestSchema,
   CallToolResult,
   CallToolResultSchema,
   Implementation,
+  ListToolsRequest,
+  ListToolsRequestSchema,
   LoggingMessageNotification,
   Notification,
   PingRequestSchema,
@@ -47,6 +50,10 @@ type AppOptions = ProtocolOptions & {
   autoResize?: boolean;
 };
 
+type RequestHandlerExtra = Parameters<
+  Parameters<App["setRequestHandler"]>[1]
+>[1];
+
 export class App extends Protocol<Request, Notification, Result> {
   private _hostCapabilities?: McpUiHostCapabilities;
   private _hostInfo?: Implementation;
@@ -64,6 +71,14 @@ export class App extends Protocol<Request, Notification, Result> {
     });
   }
 
+  getHostCapabilities(): McpUiHostCapabilities | undefined {
+    return this._hostCapabilities;
+  }
+
+  getHostVersion(): Implementation | undefined {
+    return this._hostInfo;
+  }
+
   set ontoolinput(
     callback: (params: McpUiToolInputNotification["params"]) => void,
   ) {
@@ -93,6 +108,26 @@ export class App extends Protocol<Request, Notification, Result> {
       (n) => callback(n.params),
     );
   }
+  set oncalltool(
+    callback: (
+      params: CallToolRequest["params"],
+      extra: RequestHandlerExtra,
+    ) => Promise<CallToolResult>,
+  ) {
+    this.setRequestHandler(CallToolRequestSchema, (request, extra) =>
+      callback(request.params, extra),
+    );
+  }
+  set onlisttools(
+    callback: (
+      params: ListToolsRequest["params"],
+      extra: RequestHandlerExtra,
+    ) => Promise<{ tools: string[] }>,
+  ) {
+    this.setRequestHandler(ListToolsRequestSchema, (request, extra) =>
+      callback(request.params, extra),
+    );
+  }
 
   assertCapabilityForMethod(method: Request["method"]): void {
     // TODO