fix(FN-XXXX): show chat streaming feedback during Claude waits

.changeset/fix-chat-streaming-feedback.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Keep chat and quick chat visibly in a connecting or thinking state during long Claude CLI responses, and repair missing spaces in some streamed sentence boundaries.

packages/dashboard/app/components/ChatView.tsx

@@ -823,7 +823,7 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
     const messagesContainer = messagesContainerRef.current;
     if (!messagesContainer) return;
     messagesContainer.scrollTop = messagesContainer.scrollHeight;
-  }, [messages, streamingText]);
+  }, [messages, streamingText, streamingThinking, isStreaming]);
 
   useEffect(() => {
     if (keyboardOverlap <= 0) {
@@ -1587,7 +1587,58 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
 
         {/* Messages */}
         <div className="chat-messages" ref={messagesContainerRef}>
-          {messagesLoading ? (
+          {isStreaming ? (
+            <>
+              {messages.map((message) => (
+                <ChatMessageItem
+                  key={message.id}
+                  message={message}
+                  forcePlain={plainTextMessageIds.has(message.id)}
+                  agentName={agentName}
+                  showAssistantModelTag={showAssistantModelTag}
+                  activeModelTag={activeModelTag}
+                  activeSessionId={activeSession?.id ?? null}
+                  mentionAgentsByName={mentionAgentsByName}
+                  onToggleRender={toggleMessageRenderMode}
+                />
+              ))}
+              <div className="chat-message chat-message--assistant chat-message--streaming">
+                <div className="chat-message-avatar">
+                  <Bot size={14} />
+                  <span>{agentName}</span>
+                  {showAssistantModelTag && <span className="chat-model-tag">{activeModelTag}</span>}
+                  <button
+                    type="button"
+                    className={`chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " chat-message-render-toggle--plain" : ""}`}
+                    data-testid="chat-message-render-toggle"
+                    aria-label={plainTextMessageIds.has("__streaming__") ? "Show rendered markdown" : "Show plain text"}
+                    onClick={() => toggleMessageRenderMode("__streaming__")}
+                  >
+                    {plainTextMessageIds.has("__streaming__") ? <EyeOff size={14} /> : <Eye size={14} />}
+                  </button>
+                </div>
+                {streamingText ? (
+                  renderAssistantContent(streamingText, plainTextMessageIds.has("__streaming__"))
+                ) : (
+                  <div className="chat-message-content chat-message-content--waiting">
+                    {streamingThinking ? "Thinking…" : "Connecting…"}
+                  </div>
+                )}
+                {renderToolCalls(streamingToolCalls)}
+                {streamingThinking && (
+                  <details className="chat-message-thinking">
+                    <summary>Thinking</summary>
+                    <pre className="chat-message-thinking-content">{streamingThinking}</pre>
+                  </details>
+                )}
+                <div className="chat-typing-indicator">
+                  <span />
+                  <span />
+                  <span />
+                </div>
+              </div>
+            </>
+          ) : messagesLoading ? (
             <div style={{ color: "var(--text-secondary)", fontSize: "13px" }}>Loading messages...</div>
           ) : messages.length === 0 && !activeSession ? (
             renderEmptyState()
@@ -1610,43 +1661,6 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
                   onToggleRender={toggleMessageRenderMode}
                 />
               ))}
-              {isStreaming && (
-                <div className="chat-message chat-message--assistant chat-message--streaming">
-                  <div className="chat-message-avatar">
-                    <Bot size={14} />
-                    <span>{agentName}</span>
-                    {showAssistantModelTag && <span className="chat-model-tag">{activeModelTag}</span>}
-                    <button
-                      type="button"
-                      className={`chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " chat-message-render-toggle--plain" : ""}`}
-                      data-testid="chat-message-render-toggle"
-                      aria-label={plainTextMessageIds.has("__streaming__") ? "Show rendered markdown" : "Show plain text"}
-                      onClick={() => toggleMessageRenderMode("__streaming__")}
-                    >
-                      {plainTextMessageIds.has("__streaming__") ? <EyeOff size={14} /> : <Eye size={14} />}
-                    </button>
-                  </div>
-                  {streamingText ? (
-                    renderAssistantContent(streamingText, plainTextMessageIds.has("__streaming__"))
-                  ) : (
-                    <div className="chat-message-content chat-message-content--waiting">
-                      {streamingThinking ? "Thinking…" : "Connecting…"}
-                    </div>
-                  )}
-                  {renderToolCalls(streamingToolCalls)}
-                  {streamingThinking && (
-                    <details className="chat-message-thinking">
-                      <summary>Thinking</summary>
-                      <pre className="chat-message-thinking-content">{streamingThinking}</pre>
-                    </details>
-                  )}
-                  <div className="chat-typing-indicator">
-                    <span />
-                    <span />
-                    <span />
-                  </div>
-                </div>
-              )}
             </>
           )}
           <div ref={messagesEndRef} />

packages/dashboard/app/components/QuickChatFAB.tsx

@@ -1289,7 +1289,7 @@ export function QuickChatFAB({
     const messagesEl = messagesRef.current;
     if (!messagesEl) return;
     messagesEl.scrollTop = messagesEl.scrollHeight;
-  }, [messages, streamingText, streamingThinking, isOpen]);
+  }, [messages, streamingText, streamingThinking, isStreaming, isOpen]);
 
   const sessionOptions = useMemo(
     () => sessions.map((session, index) => ({
@@ -2043,7 +2043,53 @@ export function QuickChatFAB({
           )}
 
           <div className="quick-chat-panel-messages" ref={messagesRef} data-testid="quick-chat-messages">
-            {sessionsLoading || messagesLoading ? (
+            {sessionsLoading ? (
+              <div className="quick-chat-panel-empty">Loading conversation…</div>
+            ) : isStreaming ? (
+              <>
+                {messages.map((message: ChatMessageInfo) => (
+                  <QuickChatMessageItem
+                    key={message.id}
+                    message={message}
+                    forcePlain={message.role !== "user" && plainTextMessageIds.has(message.id)}
+                    mentionAgentsByName={mentionAgentsByName}
+                    onToggleRender={toggleMessageRenderMode}
+                  />
+                ))}
+                <div
+                  className="quick-chat-panel-message quick-chat-panel-message--received quick-chat-panel-message--streaming"
+                  data-testid="quick-chat-streaming-message"
+                >
+                  {streamingText ? (
+                    <>
+                      <div data-testid="quick-chat-streaming-text">
+                        {renderAssistantMessageContent(streamingText, plainTextMessageIds.has("__streaming__"))}
+                      </div>
+                      <button
+                        type="button"
+                        className={`quick-chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " quick-chat-message-render-toggle--plain" : ""}`}
+                        data-testid="quick-chat-message-render-toggle"
+                        aria-label={plainTextMessageIds.has("__streaming__") ? "Show rendered markdown" : "Show plain text"}
+                        onClick={() => toggleMessageRenderMode("__streaming__")}
+                      >
+                        {plainTextMessageIds.has("__streaming__") ? <EyeOff size={14} /> : <Eye size={14} />}
+                      </button>
+                    </>
+                  ) : (
+                    <p className="quick-chat-panel-waiting" data-testid="quick-chat-waiting">
+                      {streamingThinking ? "Thinking…" : "Connecting…"}
+                    </p>
+                  )}
+                  {renderToolCalls(streamingToolCalls, true)}
+                  {streamingThinking && (
+                    <details className="chat-message-thinking" data-testid="quick-chat-streaming-thinking">
+                      <summary>Thinking</summary>
+                      <pre className="chat-message-thinking-content">{streamingThinking}</pre>
+                    </details>
+                  )}
+                </div>
+              </>
+            ) : messagesLoading ? (
               <div className="quick-chat-panel-empty">Loading conversation…</div>
             ) : messages.length === 0 && !streamingText && !streamingThinking && !isStreaming ? (
               <div className="quick-chat-panel-empty">No messages yet. Start the conversation!</div>
@@ -2058,41 +2104,6 @@ export function QuickChatFAB({
                     onToggleRender={toggleMessageRenderMode}
                   />
                 ))}
-                {/* Streaming message bubble */}
-                {isStreaming && (
-                  <div
-                    className="quick-chat-panel-message quick-chat-panel-message--received quick-chat-panel-message--streaming"
-                    data-testid="quick-chat-streaming-message"
-                  >
-                    {streamingText ? (
-                      <>
-                        <div data-testid="quick-chat-streaming-text">
-                          {renderAssistantMessageContent(streamingText, plainTextMessageIds.has("__streaming__"))}
-                        </div>
-                        <button
-                          type="button"
-                          className={`quick-chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " quick-chat-message-render-toggle--plain" : ""}`}
-                          data-testid="quick-chat-message-render-toggle"
-                          aria-label={plainTextMessageIds.has("__streaming__") ? "Show rendered markdown" : "Show plain text"}
-                          onClick={() => toggleMessageRenderMode("__streaming__")}
-                        >
-                          {plainTextMessageIds.has("__streaming__") ? <EyeOff size={14} /> : <Eye size={14} />}
-                        </button>
-                      </>
-                    ) : (
-                      <p className="quick-chat-panel-waiting" data-testid="quick-chat-waiting">
-                        Thinking…
-                      </p>
-                    )}
-                    {renderToolCalls(streamingToolCalls, true)}
-                    {streamingThinking && (
-                      <details className="chat-message-thinking" data-testid="quick-chat-streaming-thinking">
-                        <summary>Thinking</summary>
-                        <pre className="chat-message-thinking-content">{streamingThinking}</pre>
-                      </details>
-                    )}
-                  </div>
-                )}
               </>
             )}
           </div>

packages/dashboard/app/components/__tests__/ChatView.test.tsx

@@ -1512,6 +1512,24 @@ describe("ChatView", () => {
   });
 
   describe("streaming states", () => {
+    it("keeps the streaming indicator visible while message history is still loading", () => {
+      setupMockChat({
+        activeSession: { id: "session-001", agentId: "agent-001", status: "active", title: "Test Chat", createdAt: "2026-04-08T00:00:00.000Z", updatedAt: "2026-04-08T00:00:00.000Z" },
+        messages: [],
+        messagesLoading: true,
+        isStreaming: true,
+        streamingText: "",
+        streamingThinking: "",
+      });
+
+      render(<ChatView projectId="proj-123" addToast={vi.fn()} />);
+
+      const streamingMessage = document.querySelector(".chat-message--streaming") as HTMLElement | null;
+      expect(streamingMessage).toBeInTheDocument();
+      expect(streamingMessage?.textContent).toContain("Connecting");
+      expect(screen.queryByText("Loading messages...")).not.toBeInTheDocument();
+    });
+
     it("shows waiting indicator when streaming starts before text arrives", () => {
       setupMockChat({
         activeSession: { id: "session-001", agentId: "agent-001", status: "active", title: "Test Chat", createdAt: "2026-04-08T00:00:00.000Z", updatedAt: "2026-04-08T00:00:00.000Z" },

packages/dashboard/app/components/__tests__/QuickChatFAB.test.tsx

@@ -57,6 +57,16 @@ const agentSession: ChatSession = {
   updatedAt: new Date().toISOString(),
 };
 
+function createDeferredPromise<T>() {
+  let resolve!: (value: T | PromiseLike<T>) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
 describe("QuickChatFAB session-first UX", () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -183,4 +193,23 @@ describe("QuickChatFAB session-first UX", () => {
     });
     expect(mockCreateChatSession).not.toHaveBeenCalled();
   });
+
+  it("shows the streaming indicator instead of the loading placeholder while waiting for a long reply", async () => {
+    const deferredMessages = createDeferredPromise<{ messages: never[] }>();
+    mockFetchChatMessages.mockImplementation(() => deferredMessages.promise);
+    mockStreamChatResponse.mockImplementation(() => ({ close: vi.fn(), isConnected: () => false }));
+
+    render(<QuickChatFAB addToast={vi.fn()} projectId="proj-1" />);
+    fireEvent.click(screen.getByTestId("quick-chat-fab"));
+
+    const input = await screen.findByTestId("quick-chat-input");
+    await waitFor(() => expect(input).not.toBeDisabled());
+
+    fireEvent.change(input, { target: { value: "Explain the current architecture" } });
+    fireEvent.click(screen.getByTestId("quick-chat-send"));
+
+    expect(await screen.findByTestId("quick-chat-streaming-message")).toBeInTheDocument();
+    expect(screen.getByTestId("quick-chat-waiting")).toHaveTextContent("Connecting…");
+    expect(screen.queryByText("Loading conversation…")).not.toBeInTheDocument();
+  });
 });

packages/pi-claude-cli/src/__tests__/event-bridge.test.ts

@@ -178,6 +178,89 @@ describe("createEventBridge", () => {
       expect(textEnd1.contentIndex).toBe(1);
       expect(textEnd1.content).toBe("Second");
     });
+
+    it("repairs a missing sentence boundary between consecutive text blocks", () => {
+      const bridge = createBridgeWithStart();
+
+      bridge.handleEvent({
+        type: "content_block_start",
+        index: 0,
+        content_block: { type: "text", text: "" },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 0,
+        delta: { type: "text_delta", text: "compare them." },
+      });
+      bridge.handleEvent({
+        type: "content_block_stop",
+        index: 0,
+      });
+
+      bridge.handleEvent({
+        type: "content_block_start",
+        index: 1,
+        content_block: { type: "text", text: "" },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 1,
+        delta: { type: "text_delta", text: "Good overview." },
+      });
+
+      const output = bridge.getOutput();
+      const combinedText = output.content
+        .filter((content): content is any => content.type === "text")
+        .map((content: any) => content.text)
+        .join("");
+
+      expect(combinedText).toBe("compare them. Good overview.");
+      expect(stream.events[4]).toEqual(
+        expect.objectContaining({
+          type: "text_delta",
+          contentIndex: 1,
+          delta: " Good overview.",
+        }),
+      );
+    });
+
+    it("does not insert spaces into lowercase continuations like property access", () => {
+      const bridge = createBridgeWithStart();
+
+      bridge.handleEvent({
+        type: "content_block_start",
+        index: 0,
+        content_block: { type: "text", text: "" },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 0,
+        delta: { type: "text_delta", text: "console." },
+      });
+      bridge.handleEvent({
+        type: "content_block_stop",
+        index: 0,
+      });
+
+      bridge.handleEvent({
+        type: "content_block_start",
+        index: 1,
+        content_block: { type: "text", text: "" },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 1,
+        delta: { type: "text_delta", text: "log('hi')" },
+      });
+
+      const output = bridge.getOutput();
+      const combinedText = output.content
+        .filter((content): content is any => content.type === "text")
+        .map((content: any) => content.text)
+        .join("");
+
+      expect(combinedText).toBe("console.log('hi')");
+    });
   });
 
   describe("message_start usage tracking", () => {
@@ -795,6 +878,30 @@ describe("createEventBridge", () => {
       expect(thinkingBlock.thinking).toBe("First thought. Second thought.");
     });
 
+    it("repairs a missing sentence boundary between thinking deltas", () => {
+      const bridge = createBridgeWithStart();
+
+      bridge.handleEvent({
+        type: "content_block_start",
+        index: 0,
+        content_block: { type: "thinking" },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 0,
+        delta: { type: "thinking_delta", thinking: "I will inspect the hook." },
+      });
+      bridge.handleEvent({
+        type: "content_block_delta",
+        index: 0,
+        delta: { type: "thinking_delta", thinking: "Good, now the component." },
+      });
+
+      const output = bridge.getOutput();
+      const thinkingBlock = output.content[0] as any;
+      expect(thinkingBlock.thinking).toBe("I will inspect the hook. Good, now the component.");
+    });
+
     it("emits thinking_end for thinking block stop", () => {
       const bridge = createBridgeWithStart();
 

packages/pi-claude-cli/src/event-bridge.ts

@@ -60,6 +60,29 @@ function mapStopReason(
   }
 }
 
+function normalizeStreamingDelta(previousText: string, nextDelta: string): string {
+  if (!previousText || !nextDelta) {
+    return nextDelta;
+  }
+
+  const previousChar = previousText.slice(-1);
+  const nextChar = nextDelta[0] ?? "";
+
+  if (/\s/.test(previousChar) || /\s/.test(nextChar)) {
+    return nextDelta;
+  }
+
+  // Claude sometimes splits adjacent sentences across separate deltas or text
+  // blocks without preserving the separating space. Only repair the specific
+  // "sentence punctuation + uppercase/quoted sentence start" case so code,
+  // domains, and lowercase continuations remain untouched.
+  if (/[.!?]/.test(previousChar) && /[A-Z0-9"'([]/.test(nextChar)) {
+    return ` ${nextDelta}`;
+  }
+
+  return nextDelta;
+}
+
 /**
  * Create an event bridge that translates Claude API streaming events
  * into pi's AssistantMessageEventStream events.
@@ -98,6 +121,19 @@ export function createEventBridge(
 
   let started = false;
 
+  function getPreviousContentText(contentIndex: number, type: "text" | "thinking"): string {
+    for (let i = contentIndex - 1; i >= 0; i--) {
+      const contentBlock = output.content[i];
+      if (type === "text" && contentBlock?.type === "text") {
+        return contentBlock.text;
+      }
+      if (type === "thinking" && contentBlock?.type === "thinking") {
+        return contentBlock.thinking;
+      }
+    }
+    return "";
+  }
+
   function handleEvent(event: ClaudeApiEvent): void {
     // Emit start event on first message — tells pi to begin incremental rendering
     if (!started) {
@@ -226,14 +262,18 @@ export function createEventBridge(
 
       const block = blocks[idx];
       if (block.type === "text") {
-        block.text += event.delta!.text;
+        const delta = normalizeStreamingDelta(
+          block.text || getPreviousContentText(idx, "text"),
+          event.delta!.text,
+        );
+        block.text += delta;
         const contentBlock = output.content[idx] as TextContent;
         contentBlock.text = block.text;
 
         stream.push({
           type: "text_delta",
           contentIndex: idx,
-          delta: event.delta!.text,
+          delta,
           partial: output,
         });
       }
@@ -246,14 +286,18 @@ export function createEventBridge(
 
       const block = blocks[idx];
       if (block.type === "thinking") {
-        block.text += event.delta!.thinking;
+        const delta = normalizeStreamingDelta(
+          block.text || getPreviousContentText(idx, "thinking"),
+          event.delta!.thinking,
+        );
+        block.text += delta;
         const contentBlock = output.content[idx] as ThinkingContent;
         contentBlock.thinking = block.text;
 
         stream.push({
           type: "thinking_delta",
           contentIndex: idx,
-          delta: event.delta!.thinking,
+          delta,
           partial: output,
         });
       }