- Demo is deployed and accessible at
/demos/mcp-appson the dashboard host - Agent backend is healthy;
OPENAI_API_KEYis set on Railway;LANGGRAPH_DEPLOYMENT_URLpoints at a LangGraph deployment exposing themcp_appsgraph (registered as agent namemcp-apps— seesrc/app/api/copilotkit-mcp-apps/route.ts) - MCP server target: the public Excalidraw MCP app at
https://mcp.excalidraw.com(override viaMCP_SERVER_URL). PinnedserverId: "excalidraw"so URL changes don't silently break persisted activities - Note: the demo source contains no
data-testidattributes and registers no custom activity renderer — CopilotKit's built-inMCPAppsActivityRendererhandles the sandboxed iframe automatically. Checks below rely on verbatim visible text, network traffic, and the iframe DOM
- Navigate to
/demos/mcp-apps; verify the page renders within 3s and a singleCopilotChatpane is centered (max-width ~896px, rounded-2xl, full-height) - Verify the chat is wired to
runtimeUrl="/api/copilotkit-mcp-apps"andagent="mcp-apps"(DevTools → Network: sending a message hits that endpoint) - Verify both suggestion pills are visible with verbatim titles:
- "Draw a flowchart"
- "Sketch a system diagram"
- Send "Hello" and verify an assistant text response appears within 10s (no MCP activity iframe for plain text)
- Send the first flow-chart prompt; in DevTools → Network, verify the POST to
/api/copilotkit-mcp-appssucceeds (status 200) and the server-side runtime resolves tools fromhttps://mcp.excalidraw.com(watch the server logs for the MCP Apps middleware attaching the Excalidraw tool set — notablycreate_view) - Verify no console errors mentioning the MCP server URL, auth, or tool-schema parse failures
- Click "Draw a flowchart"; within 60s verify the agent calls the
create_viewMCP tool exactly ONCE (perSYSTEM_PROMPTinsrc/agents/mcp_apps_agent.py: "Callcreate_viewONCE with 3-5 elements total") — confirm via DevTools → Network stream or backend logs - Verify the tool payload contains 3-5 Excalidraw elements (shapes + arrows + optional title text), each with a unique string
id, and ends with ONEcameraUpdatesized600x450or800x600
- Within 60s of the tool call, verify a sandboxed
<iframe>renders inline in the chat transcript (activity-message slot) pointed at the Excalidraw MCP UI resource - Verify the iframe has a
sandboxattribute (CopilotKit's built-in renderer always sandboxes MCP UI resources) - Verify the iframe paints a flow-chart-shaped diagram: at least 3 shape nodes (rectangles, ellipses, or diamonds with text labels) connected by arrows, framed within the viewport (camera-update step from the system prompt)
- Verify the assistant text below the iframe is a single short sentence describing what was drawn (per system prompt)
- Without reloading, send the second suggestion "Sketch a system diagram"; within 60s verify a new activity iframe renders in-transcript containing a client → server → database layout (3 labeled shapes + 2 arrows)
- Verify the previous flow-chart iframe is still present and un-stale in the scrollback (activity messages persist, matching the rationale for the pinned
serverId: "excalidraw"in the runtime config)
- Send an explicit prompt:
"Use Excalidraw to draw exactly 2 rectangles labelled 'A' and 'B' connected by one arrow from A to B." - Within 60s verify: (1)
create_viewis called ONCE with exactly 3 elements (2 rectangles + 1 arrow) plus the trailingcameraUpdate; (2) an iframe renders showing two labelled rectangles with a connecting arrow; (3) the assistant reply is one short sentence; (4) no duplicatecreate_viewinvocations or retries appear in network / logs
- Send an empty message; verify it is a no-op (no user bubble, no assistant response)
- Send "What is 2+2?"; verify the agent replies in plain text without invoking
create_view(no iframe, no MCP activity in the stream) - DevTools → Console: walk through all flows above; verify no uncaught errors, no CORS failures referencing
mcp.excalidraw.com, and no "sandbox" / iframe-permission warnings
- Chat loads within 3s; plain-text response within 10s; MCP-backed iframe renders within 60s of prompt (bias is "correct-enough diagram fast" per system prompt, one
create_viewcall) - MCP server connection to
https://mcp.excalidraw.comsucceeds and the Excalidraw tool set (includingcreate_view) is advertised to the agent at request time - At least one concrete end-to-end MCP interaction completes: user prompt →
create_viewtool call → activity event → sandboxed iframe painting the requested diagram - The built-in
MCPAppsActivityRendereris used (no app-sideuseRenderActivityMessage/renderActivityMessagesregistration exists inpage.tsx— per the@region[no-frontend-renderer-needed]contract) - No UI layout breaks, no uncaught console errors, no duplicate
create_viewinvocations within a single prompt turn