DeepSeek V3.2 Thinking Mode Integration

packages/cli/src/nonInteractiveCli.test.ts

@@ -245,6 +245,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Test input' }],
       expect.any(AbortSignal),
       'prompt-id-1',
+      { isContinuation: false },
     );
     expect(processStdoutSpy).toHaveBeenCalledWith('Hello');
     expect(processStdoutSpy).toHaveBeenCalledWith(' World');
@@ -293,11 +294,21 @@ describe('runNonInteractive', () => {
       expect.any(AbortSignal),
       undefined,
     );
+    // Verify first call has isContinuation: false
+    expect(mockGeminiClient.sendMessageStream).toHaveBeenNthCalledWith(
+      1,
+      [{ text: 'Use a tool' }],
+      expect.any(AbortSignal),
+      'prompt-id-2',
+      { isContinuation: false },
+    );
+    // Verify second call (after tool execution) has isContinuation: true
     expect(mockGeminiClient.sendMessageStream).toHaveBeenNthCalledWith(
       2,
       [{ text: 'Tool response' }],
       expect.any(AbortSignal),
       'prompt-id-2',
+      { isContinuation: true },
     );
     expect(processStdoutSpy).toHaveBeenCalledWith('Final answer');
     expect(processStdoutSpy).toHaveBeenCalledWith('\n');
@@ -372,6 +383,7 @@ describe('runNonInteractive', () => {
       ],
       expect.any(AbortSignal),
       'prompt-id-3',
+      { isContinuation: true },
     );
     expect(processStdoutSpy).toHaveBeenCalledWith('Sorry, let me try again.');
   });
@@ -497,6 +509,7 @@ describe('runNonInteractive', () => {
       processedParts,
       expect.any(AbortSignal),
       'prompt-id-7',
+      { isContinuation: false },
     );
 
     // 6. Assert the final output is correct
@@ -528,6 +541,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Test input' }],
       expect.any(AbortSignal),
       'prompt-id-1',
+      { isContinuation: false },
     );
 
     // JSON adapter emits array of messages, last one is result with stats
@@ -680,6 +694,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Empty response test' }],
       expect.any(AbortSignal),
       'prompt-id-empty',
+      { isContinuation: false },
     );
 
     // JSON adapter emits array of messages, last one is result with stats
@@ -831,6 +846,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Prompt from command' }],
       expect.any(AbortSignal),
       'prompt-id-slash',
+      { isContinuation: false },
     );
 
     expect(processStdoutSpy).toHaveBeenCalledWith('Response from command');
@@ -887,6 +903,7 @@ describe('runNonInteractive', () => {
       [{ text: '/unknowncommand' }],
       expect.any(AbortSignal),
       'prompt-id-unknown',
+      { isContinuation: false },
     );
 
     expect(processStdoutSpy).toHaveBeenCalledWith('Response to unknown');
@@ -1217,6 +1234,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Message from stream-json input' }],
       expect.any(AbortSignal),
       'prompt-envelope',
+      { isContinuation: false },
     );
   });
 
@@ -1692,6 +1710,7 @@ describe('runNonInteractive', () => {
       [{ text: 'Simple string content' }],
       expect.any(AbortSignal),
       'prompt-string-content',
+      { isContinuation: false },
     );
 
     // UserMessage with array of text blocks
@@ -1724,6 +1743,7 @@ describe('runNonInteractive', () => {
       [{ text: 'First part' }, { text: 'Second part' }],
       expect.any(AbortSignal),
       'prompt-blocks-content',
+      { isContinuation: false },
     );
   });
 });

packages/cli/src/nonInteractiveCli.ts

@@ -170,6 +170,7 @@ export async function runNonInteractive(
         adapter.emitMessage(systemMessage);
       }
 
+      let isFirstTurn = true;
       while (true) {
         turnCount++;
         if (
@@ -185,7 +186,9 @@ export async function runNonInteractive(
           currentMessages[0]?.parts || [],
           abortController.signal,
           prompt_id,
+          { isContinuation: !isFirstTurn },
         );
+        isFirstTurn = false;
 
         // Start assistant message for this turn
         if (adapter) {
@@ -205,7 +208,9 @@ export async function runNonInteractive(
             }
           } else {
             // Text output mode - direct stdout
-            if (event.type === GeminiEventType.Content) {
+            if (event.type === GeminiEventType.Thought) {
+              process.stdout.write(event.value.description);
+            } else if (event.type === GeminiEventType.Content) {
               process.stdout.write(event.value);
             } else if (event.type === GeminiEventType.ToolCallRequest) {
               toolCallRequests.push(event.value);

packages/cli/src/ui/components/HistoryItemDisplay.tsx

@@ -15,6 +15,8 @@ import { InfoMessage } from './messages/InfoMessage.js';
 import { ErrorMessage } from './messages/ErrorMessage.js';
 import { ToolGroupMessage } from './messages/ToolGroupMessage.js';
 import { GeminiMessageContent } from './messages/GeminiMessageContent.js';
+import { GeminiThoughtMessage } from './messages/GeminiThoughtMessage.js';
+import { GeminiThoughtMessageContent } from './messages/GeminiThoughtMessageContent.js';
 import { CompressionMessage } from './messages/CompressionMessage.js';
 import { SummaryMessage } from './messages/SummaryMessage.js';
 import { WarningMessage } from './messages/WarningMessage.js';
@@ -85,6 +87,26 @@ const HistoryItemDisplayComponent: React.FC<HistoryItemDisplayProps> = ({
           terminalWidth={terminalWidth}
         />
       )}
+      {itemForDisplay.type === 'gemini_thought' && (
+        <GeminiThoughtMessage
+          text={itemForDisplay.text}
+          isPending={isPending}
+          availableTerminalHeight={
+            availableTerminalHeightGemini ?? availableTerminalHeight
+          }
+          terminalWidth={terminalWidth}
+        />
+      )}
+      {itemForDisplay.type === 'gemini_thought_content' && (
+        <GeminiThoughtMessageContent
+          text={itemForDisplay.text}
+          isPending={isPending}
+          availableTerminalHeight={
+            availableTerminalHeightGemini ?? availableTerminalHeight
+          }
+          terminalWidth={terminalWidth}
+        />
+      )}
       {itemForDisplay.type === 'info' && (
         <InfoMessage text={itemForDisplay.text} />
       )}

packages/cli/src/ui/components/messages/GeminiThoughtMessage.tsx

@@ -0,0 +1,48 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type React from 'react';
+import { Text, Box } from 'ink';
+import { MarkdownDisplay } from '../../utils/MarkdownDisplay.js';
+import { theme } from '../../semantic-colors.js';
+
+interface GeminiThoughtMessageProps {
+  text: string;
+  isPending: boolean;
+  availableTerminalHeight?: number;
+  terminalWidth: number;
+}
+
+/**
+ * Displays model thinking/reasoning text with a softer, dimmed style
+ * to visually distinguish it from regular content output.
+ */
+export const GeminiThoughtMessage: React.FC<GeminiThoughtMessageProps> = ({
+  text,
+  isPending,
+  availableTerminalHeight,
+  terminalWidth,
+}) => {
+  const prefix = '✦ ';
+  const prefixWidth = prefix.length;
+
+  return (
+    <Box flexDirection="row" marginBottom={1}>
+      <Box width={prefixWidth}>
+        <Text color={theme.text.secondary}>{prefix}</Text>
+      </Box>
+      <Box flexGrow={1} flexDirection="column">
+        <MarkdownDisplay
+          text={text}
+          isPending={isPending}
+          availableTerminalHeight={availableTerminalHeight}
+          terminalWidth={terminalWidth}
+          textColor={theme.text.secondary}
+        />
+      </Box>
+    </Box>
+  );
+};

packages/cli/src/ui/components/messages/GeminiThoughtMessageContent.tsx

@@ -0,0 +1,40 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type React from 'react';
+import { Box } from 'ink';
+import { MarkdownDisplay } from '../../utils/MarkdownDisplay.js';
+import { theme } from '../../semantic-colors.js';
+
+interface GeminiThoughtMessageContentProps {
+  text: string;
+  isPending: boolean;
+  availableTerminalHeight?: number;
+  terminalWidth: number;
+}
+
+/**
+ * Continuation component for thought messages, similar to GeminiMessageContent.
+ * Used when a thought response gets too long and needs to be split for performance.
+ */
+export const GeminiThoughtMessageContent: React.FC<
+  GeminiThoughtMessageContentProps
+> = ({ text, isPending, availableTerminalHeight, terminalWidth }) => {
+  const originalPrefix = '✦ ';
+  const prefixWidth = originalPrefix.length;
+
+  return (
+    <Box flexDirection="column" paddingLeft={prefixWidth} marginBottom={1}>
+      <MarkdownDisplay
+        text={text}
+        isPending={isPending}
+        availableTerminalHeight={availableTerminalHeight}
+        terminalWidth={terminalWidth}
+        textColor={theme.text.secondary}
+      />
+    </Box>
+  );
+};

packages/cli/src/ui/hooks/useGeminiStream.test.tsx

@@ -2261,6 +2261,57 @@ describe('useGeminiStream', () => {
       });
     });
 
+    it('should accumulate streamed thought descriptions', async () => {
+      mockSendMessageStream.mockReturnValue(
+        (async function* () {
+          yield {
+            type: ServerGeminiEventType.Thought,
+            value: { subject: '', description: 'thinking ' },
+          };
+          yield {
+            type: ServerGeminiEventType.Thought,
+            value: { subject: '', description: 'more' },
+          };
+          yield {
+            type: ServerGeminiEventType.Finished,
+            value: { reason: 'STOP', usageMetadata: undefined },
+          };
+        })(),
+      );
+
+      const { result } = renderHook(() =>
+        useGeminiStream(
+          new MockedGeminiClientClass(mockConfig),
+          [],
+          mockAddItem,
+          mockConfig,
+          mockLoadedSettings,
+          mockOnDebugMessage,
+          mockHandleSlashCommand,
+          false,
+          () => 'vscode' as EditorType,
+          () => {},
+          () => Promise.resolve(),
+          false,
+          () => {},
+          () => {},
+          () => {},
+          false, // visionModelPreviewEnabled
+          () => {},
+          80,
+          24,
+        ),
+      );
+
+      await act(async () => {
+        await result.current.submitQuery('Streamed thought');
+      });
+
+      await waitFor(() => {
+        expect(result.current.thought?.description).toBe('thinking more');
+      });
+    });
+
     it('should memoize pendingHistoryItems', () => {
       mockUseReactToolScheduler.mockReturnValue([
         [],