TUI: keep streamed text when final output is empty

Closes #747

src/tui/components/chat-log.ts

@@ -49,6 +49,14 @@ export class ChatLog extends Container {
     this.streamingAssistant.setText(text);
   }
 
+  getStreamingText(runId?: string) {
+    if (!this.streamingAssistant) return null;
+    if (runId && this.streamingRunId && runId !== this.streamingRunId) {
+      return null;
+    }
+    return this.streamingText;
+  }
+
   finalizeAssistant(text: string, runId?: string) {
     if (
       this.streamingAssistant &&

src/tui/tui.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+
+import { resolveFinalAssistantText } from "./tui.js";
+
+describe("resolveFinalAssistantText", () => {
+  it("falls back to streamed text when final text is empty", () => {
+    expect(
+      resolveFinalAssistantText({ finalText: "", streamedText: "Hello" }),
+    ).toBe("Hello");
+  });
+
+  it("prefers the final text when present", () => {
+    expect(
+      resolveFinalAssistantText({
+        finalText: "All done",
+        streamedText: "partial",
+      }),
+    ).toBe("All done");
+  });
+});

src/tui/tui.ts

@@ -39,6 +39,17 @@ export type TuiOptions = {
   message?: string;
 };
 
+export function resolveFinalAssistantText(params: {
+  finalText?: string | null;
+  streamedText?: string | null;
+}) {
+  const finalText = params.finalText ?? "";
+  if (finalText.trim()) return finalText;
+  const streamedText = params.streamedText ?? "";
+  if (streamedText.trim()) return streamedText;
+  return "(no output)";
+}
+
 type ChatEvent = {
   runId: string;
   sessionKey: string;
@@ -642,7 +653,11 @@ export async function runTui(opts: TuiOptions) {
       const text = extractTextFromMessage(evt.message, {
         includeThinking: showThinking,
       });
-      chatLog.finalizeAssistant(text || "(no output)", evt.runId);
+      const finalText = resolveFinalAssistantText({
+        finalText: text,
+        streamedText: chatLog.getStreamingText(evt.runId),
+      });
+      chatLog.finalizeAssistant(finalText, evt.runId);
       noteFinalizedRun(evt.runId);
       activeChatRunId = null;
       setActivityStatus("idle");