QA: Headless Chat (Complete) — LangGraph (Python)

Prerequisites

• Demo is deployed and accessible at /demos/headless-complete on the dashboard host
• Agent backend is healthy (/api/health); OPENAI_API_KEY is set on Railway; LANGGRAPH_DEPLOYMENT_URL points at a LangGraph deployment exposing the headless_complete graph (backend tools: get_weather, get_stock_price)
• The demo wires agent="headless-complete" at /api/copilotkit-mcp-apps (shared with the mcp-apps cell) so the Excalidraw MCP server at MCP_SERVER_URL || https://mcp.excalidraw.com is available
• Note: the only data-testid in the source is headless-complete-messages on the scrollable messages container in message-list.tsx. Other checks rely on verbatim text, role selectors, and Tailwind utility classes

Test Steps

1. Basic Functionality

• Navigate to /demos/headless-complete; verify the page renders within 3s with a centered card (max-width 3xl, full-height) on a bg-gray-50 background
• Verify the custom header renders with <h1> text "Headless Chat (Complete)" and subtext "Built from scratch on useAgent — no CopilotChat."
• Verify the scrollable messages container ([data-testid="headless-complete-messages"]) is present and shows the empty-state hint "Try weather, a stock, a highlighted note, or an Excalidraw sketch."
• Verify the custom composer renders at the bottom: a <textarea> with placeholder "Type a message..." and a <button type="submit">Send</button> (disabled while textarea is empty)
• Confirm there is no .copilotKitChat, .copilotKitMessages, or .copilotKitMessage element in the DOM — the cell is truly headless and does NOT render <CopilotChatMessageView> or <CopilotChatAssistantMessage>

2. Feature-Specific Checks

Custom Composer + Send/Stop Toggle

• Type "Hello"; verify the Send button enables (goes from bg-[#DBDBE5] disabled to bg-[#010507] active)
• Press Enter; verify the message submits and the textarea clears; press Shift+Enter in a follow-up message and verify a newline is inserted without submitting
• While the agent is running, verify the textarea becomes disabled (bg-[#FAFAFC] muted), its placeholder switches to "Agent is working...", and the right-hand button swaps from "Send" to a red bg-[#FA5F67] "Stop" button
• Click "Stop" mid-stream; verify copilotkit.stopAgent({ agent }) fires and the button reverts to "Send" once isRunning returns false

Message List + Bubbles (pure chrome)

• Send "Hello"; within 10s verify:
  • A user bubble renders right-aligned (flex justify-end), rounded with rounded-2xl rounded-br-sm, bg-[#010507] text-white at max-w-[75%], text "Hello"
  • A typing indicator (small pulsing gray dot in a bg-[#F0F0F4] rounded bubble) appears while isRunning is true and BEFORE any assistant content has streamed
  • The assistant bubble renders left-aligned (flex justify-start), rounded-2xl rounded-bl-sm, bg-[#F0F0F4] text-[#010507] at max-w-[85%], with the assistant's plain-text response inside a whitespace-pre-wrap break-words div
• Verify the messages container auto-scrolls to the bottom on each content-length change (send a long prompt whose response exceeds the viewport — scroll position should track the last line)
• Verify empty assistant messages (mid-stream before any text/tool call) do NOT flash an empty bg-[#F0F0F4] box — AssistantBubble's isEmpty check suppresses them

Multi-Turn Conversation

• Send a second message ("What else can you do?"); verify the prior user+assistant pair remain in the transcript in chronological order and the new pair is appended below
• Verify each assistant bubble is independently sized (does not collapse neighbors) and the auto-scroll follows the newest content

Tool Rendering — WeatherCard (useRenderTool + backend get_weather)

• Send "What's the weather in Tokyo?"; within 15s verify a WeatherCard in the assistant bubble with eyebrow "FETCHING WEATHER" (loading) → "WEATHER" (complete), location "Tokyo" (text-sm font-semibold capitalize), temperature "68°", conditions "Sunny", wrapper bg-[#EDEDF5] border-[#DBDBE5] rounded-xl max-w-xs

Tool Rendering — StockCard (useRenderTool + backend get_stock_price)

• Send "What's AAPL trading at right now?"; within 15s verify a StockCard with eyebrow "LOADING" → "STOCK", ticker "AAPL" (font-mono font-semibold), price "$189.42", change "▲ 1.27%" in green text-[#189370]

Frontend Tool Rendering — HighlightNote (useComponent / highlight_note)

• Send "Highlight 'meeting at 3pm' in yellow."; within 15s verify a HighlightNote with eyebrow "NOTE", verbatim text "meeting at 3pm", and yellow variant classes bg-[#FFF388]/30 border-[#FFF388]
• Optionally request pink/green/blue and verify corresponding COLOR_CLASSES are applied

Wildcard Catch-all + MCP Apps Activity (useDefaultRenderTool + useRenderActivityMessage)

• Send "Use Excalidraw to sketch a simple system diagram."; within 30s verify:
  • The activity message renders inline as a sandboxed Excalidraw iframe (built-in MCPAppsActivityRenderer), proving the hand-rolled useRenderActivityMessage path in use-rendered-messages.tsx
  • Any ancillary tool-call (not get_weather / get_stock_price / highlight_note) gets a visible default card via useDefaultRenderTool — not silently dropped
  • DevTools → Console shows no errors referencing the MCP server URL

Reasoning + Suggestions

• If the agent emits any role: "reasoning" messages, verify each renders via the imported CopilotChatReasoningMessage leaf inside an assistant bubble (the only chat primitive imported in use-rendered-messages.tsx)
• Four suggestion strings are registered via useConfigureSuggestions with available: "always" ("Weather in Tokyo", "AAPL stock price", "Highlight a note", "Sketch a diagram") — exercised by manually sending the matching prompts above

3. Error Handling

• Attempt to submit an empty textarea; verify the Send button is disabled and Enter is a no-op (no user bubble, no run)
• While isRunning is true, verify additional keystrokes cannot trigger a second run (handleSubmit's if (!text || isRunning) return; guard)
• Send a ~500-character message; verify the user bubble wraps within its 75% max-width via break-words without horizontal scroll
• Navigate away mid-run; verify the unmount cleanup (ac.abort() + agent.detachActiveRun()) does not produce an uncaught rejection in DevTools → Console (connect/run rejections are swallowed by design)
• With the backend stopped, send a message; verify console.error("headless-complete: runAgent failed", err) is emitted but no uncaught exception leaks, and the Send/Stop UI recovers to the idle state

Expected Results

• Page loads within 3 seconds; first plain-text response within 10 seconds
• Tool renders (WeatherCard, StockCard, HighlightNote) surface within 15 seconds of the triggering prompt
• Excalidraw MCP activity surface renders within 30 seconds
• Full generative-UI weave is reconstructed without <CopilotChatMessageView> / <CopilotChatAssistantMessage>: assistant text + tool-call renders (per-tool + catch-all) + reasoning + activity messages all appear through the hand-rolled useRenderedMessages composition
• No flash of empty assistant bubbles while streaming; no uncaught console errors during any flow above