feat: add Excalidraw MCP apps middleware and suggestion

Wire @ag-ui/mcp-apps-middleware into the CopilotKit runtime Lambda so
agents can use Excalidraw's MCP server for open generative UI. Add the
corresponding "network diagram" suggestion to the frontend.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

frontend/src/hooks/useExampleSuggestions.ts

@@ -14,6 +14,11 @@ export const useExampleSuggestions = () => {
         message:
           "Please show me the distribution of our expenses by category in a bar chart.",
       },
+      {
+        title: "MCP apps (Open Generative UI)",
+        message:
+          "Please create a simple network diagram of a router and two switches.",
+      },
       {
         title: "Change theme (Frontend Tools)",
         message: "Switch the app to dark mode.",

infra-cdk/lambdas/copilotkit-runtime/package-lock.json

@@ -9,6 +9,7 @@
   },
   "dependencies": {
     "@ag-ui/client": "^0.0.47",
+    "@ag-ui/mcp-apps-middleware": "^0.0.3",
     "@copilotkit/runtime": "^1.54.0",
     "hono": "^4.11.4",
     "rxjs": "^7.8.2"

infra-cdk/lambdas/copilotkit-runtime/package.json

@@ -1,4 +1,5 @@
 import { EventType, HttpAgent, type BaseEvent } from "@ag-ui/client"
+import { MCPAppsMiddleware } from "@ag-ui/mcp-apps-middleware"
 import { CopilotRuntime, createCopilotEndpoint, InMemoryAgentRunner } from "@copilotkit/runtime/v2"
 import { streamHandle } from "hono/aws-lambda"
 import { concatMap, of } from "rxjs"
@@ -20,9 +21,23 @@ function getConfiguredAgents(): Record<string, HttpAgent> {
     "strands-single-agent": process.env.STRANDS_AGENTCORE_AG_UI_URL,
   }
 
+  const mcpServerUrl = process.env.MCP_SERVER_URL || "https://mcp.excalidraw.com"
+
   for (const [name, url] of Object.entries(agentUrls)) {
     if (url) {
-      configuredAgents[name] = new HttpAgent({ url })
+      const agent = new HttpAgent({ url })
+      agent.use(
+        new MCPAppsMiddleware({
+          mcpServers: [
+            {
+              type: "http",
+              url: mcpServerUrl,
+              serverId: "example_mcp_app",
+            },
+          ],
+        })
+      )
+      configuredAgents[name] = agent
     }
   }