QA: Headless Chat (Complete) — Mastra

Test Steps

• Navigate to /demos/headless-complete
• Verify the custom headless chat renders (custom bubbles + input bar, no <CopilotChat />)
• Type "What's the weather in Tokyo?" and press Enter
• Verify a WeatherCard renders inline with city/temperature/conditions
• Type "What's AAPL trading at right now?"
• Verify a StockCard renders with ticker + price + % change
• Type "Highlight 'meeting at 3pm' in yellow."
• Verify a yellow HighlightNote renders inline (frontend-registered tool)
• Verify Stop button appears while the agent is running and cancels the turn

Expected Results

• Full generative-UI weave composed manually via useRenderToolCall, useRenderActivityMessage, useRenderCustomMessages
• Weather + stock tool renderers wired via useRenderTool
• highlight_note registered on the frontend via useComponent
• Wildcard catch-all renders any other tool call via useDefaultRenderTool

Known Limitations

• The langgraph-python reference wires in Excalidraw MCP tools via /api/copilotkit-mcp-apps. Mastra skips mcp-apps as a truthful architectural limitation (see PARITY_NOTES.md), so the "Sketch a diagram" suggestion is omitted.