cr

Author: idosal

src/app-bridge.test.ts

@@ -215,8 +215,9 @@ describe("App <-> AppBridge integration", () => {
 
     it("app.sendContext triggers bridge.oncontext and returns result", async () => {
       const receivedContexts: unknown[] = [];
-      bridge.oncontext = (params) => {
+      bridge.oncontext = async (params) => {
         receivedContexts.push(params);
+        return {};
       };
 
       await app.connect(appTransport);
@@ -235,8 +236,9 @@ describe("App <-> AppBridge integration", () => {
 
     it("app.sendContext works with multiple content blocks", async () => {
       const receivedContexts: unknown[] = [];
-      bridge.oncontext = (params) => {
+      bridge.oncontext = async (params) => {
         receivedContexts.push(params);
+        return {};
       };
 
       await app.connect(appTransport);
@@ -258,6 +260,20 @@ describe("App <-> AppBridge integration", () => {
       });
       expect(result).toEqual({});
     });
+
+    it("app.sendContext returns error result when handler indicates error", async () => {
+      bridge.oncontext = async () => {
+        return { isError: true };
+      };
+
+      await app.connect(appTransport);
+      const result = await app.sendContext({
+        role: "user",
+        content: [{ type: "text", text: "Test" }],
+      });
+
+      expect(result.isError).toBe(true);
+    });
   });
 
   describe("App -> Host requests", () => {

src/app-bridge.ts

@@ -41,6 +41,7 @@ import {
   McpUiAppCapabilities,
   McpUiUpdateContextRequest,
   McpUiUpdateContextRequestSchema,
+  McpUiUpdateContextResult,
   McpUiHostCapabilities,
   McpUiHostContext,
   McpUiHostContextChangedNotification,
@@ -512,30 +513,46 @@ export class AppBridge extends Protocol<Request, Notification, Result> {
    * future reasoning. Unlike logging messages, context updates are intended to be
    * available to the agent for decision making.
    *
-   * @param callback - Handler that receives context update params
+   * @param callback - Handler that receives context update params and returns a result
    *   - params.role - Message role (currently only "user")
    *   - params.content - Content blocks (text, image, etc.)
+   *   - extra - Request metadata (abort signal, session info)
+   *   - Returns: Promise<McpUiUpdateContextResult> with optional isError flag
    *
    * @example
    * ```typescript
-   * bridge.oncontext = ({ role, content }) => {
-   *   // Store context update for agent reasoning
-   *   conversationContext.push({
-   *     type: "app_context",
-   *     role,
-   *     content,
-   *     timestamp: Date.now()
-   *   });
+   * bridge.oncontext = async ({ role, content }, extra) => {
+   *   try {
+   *     // Store context update for agent reasoning
+   *     conversationContext.push({
+   *       type: "app_context",
+   *       role,
+   *       content,
+   *       timestamp: Date.now()
+   *     });
+   *     return {};
+   *   } catch (err) {
+   *     // Handle error and signal failure to the app
+   *     return { isError: true };
+   *   }
    * };
    * ```
+   *
+   * @see {@link McpUiUpdateContextRequest} for the request type
+   * @see {@link McpUiUpdateContextResult} for the result type
    */
   set oncontext(
-    callback: (params: McpUiUpdateContextRequest["params"]) => void,
+    callback: (
+      params: McpUiUpdateContextRequest["params"],
+      extra: RequestHandlerExtra,
+    ) => Promise<McpUiUpdateContextResult>,
   ) {
-    this.setRequestHandler(McpUiUpdateContextRequestSchema, async (request) => {
-      callback(request.params);
-      return {};
-    });
+    this.setRequestHandler(
+      McpUiUpdateContextRequestSchema,
+      async (request, extra) => {
+        return callback(request.params, extra);
+      },
+    );
   }
 
   /**