fix(tui): keep waiting spinner during encrypted reasoning streams (#1256)

Empty (encrypted/redacted) thinking deltas no longer switch out of waiting mode, which previously stopped the moon spinner while no thinking component was ever created, leaving a blank spinner-less gap until the first real text/tool token.

.changeset/keep-waiting-spinner-empty-reasoning.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Keep the waiting spinner visible while encrypted reasoning streams, fixing a blank spinner-less gap before the first response text appears.

apps/kimi-code/src/tui/controllers/session-event-handler.ts

@@ -438,6 +438,14 @@ export class SessionEventHandler {
 
   private handleThinkingDelta(event: ThinkingDeltaEvent): void {
     const { state, streamingUI } = this.host;
+    // Encrypted / redacted reasoning (e.g. Kimi over the Anthropic-compatible
+    // protocol) streams thinking deltas whose visible text is empty — only an
+    // opaque signature rides along. Such deltas carry nothing to render, so
+    // switching into the `thinking` pane mode here would stop the "waiting"
+    // moon spinner while no ThinkingComponent is ever created (it needs visible
+    // text), leaving a blank, spinner-less gap until the first real text/tool
+    // token arrives. Keep the moon up until actual thinking text shows up.
+    if (event.delta.length === 0 && !streamingUI.hasThinkingDraft()) return;
     streamingUI.appendThinkingDelta(event.delta);
     this.host.patchLivePane({ mode: 'idle' });
     if (state.appState.streamingPhase !== 'thinking') {

apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts

@@ -13,6 +13,7 @@ import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { ApprovalPanelComponent } from '#/tui/components/dialogs/approval-panel';
 import { KIMI_CODE_PLUGIN_MARKETPLACE_URL } from '#/constant/app';
+import { MOON_SPINNER_FRAMES } from '#/tui/constant/rendering';
 import {
   AgentSwarmProgressComponent,
   agentSwarmGridHeightForTerminalRows,
@@ -4528,6 +4529,58 @@ command = "vim"
     expect(driver.streamingUI.hasActiveThinkingComponent()).toBe(false);
   });
 
+  it('keeps the waiting moon spinner while reasoning streams only empty (encrypted) thinking deltas', async () => {
+    const { driver } = await makeDriver();
+
+    // Turn begins -> waiting mode shows the moon spinner.
+    driver.sessionEventHandler.handleEvent(
+      {
+        type: 'turn.started',
+        agentId: 'main',
+        sessionId: 'ses-1',
+        turnId: 1,
+      } as Event,
+      vi.fn(),
+    );
+    expect(driver.state.appState.streamingPhase).toBe('waiting');
+    expect(driver.state.livePane.mode).toBe('waiting');
+
+    // Encrypted reasoning: thinking.delta events whose visible text is empty.
+    for (let i = 0; i < 3; i++) {
+      driver.sessionEventHandler.handleEvent(
+        {
+          type: 'thinking.delta',
+          agentId: 'main',
+          sessionId: 'ses-1',
+          delta: '',
+        } as Event,
+        vi.fn(),
+      );
+    }
+
+    // The moon must stay up: still waiting, no orphan thinking component, and
+    // the activity pane still renders a moon frame (no blank, spinner-less gap).
+    expect(driver.state.appState.streamingPhase).toBe('waiting');
+    expect(driver.state.livePane.mode).toBe('waiting');
+    expect(driver.streamingUI.hasActiveThinkingComponent()).toBe(false);
+    const activity = stripSgr(renderActivity(driver));
+    expect(MOON_SPINNER_FRAMES.some((frame) => activity.includes(frame))).toBe(true);
+
+    // Real thinking text finally arrives -> transition into thinking mode.
+    driver.sessionEventHandler.handleEvent(
+      {
+        type: 'thinking.delta',
+        agentId: 'main',
+        sessionId: 'ses-1',
+        delta: 'actual reasoning',
+      } as Event,
+      vi.fn(),
+    );
+    driver.streamingUI.flushNow();
+    expect(driver.state.appState.streamingPhase).toBe('thinking');
+    expect(driver.streamingUI.hasActiveThinkingComponent()).toBe(true);
+  });
+
   it('finalizes an orphaned thinking component on turn end', async () => {
     const { driver } = await makeDriver();
     driver.state.appState.streamingPhase = 'thinking';