Thinking Mode

Thinking mode exposes the model's internal reasoning process as a separate response channel, so you can show a "thinking" bubble in your UI before the final answer.

Supported models#

• Gemma 4 (E2B, E4B)
• DeepSeek R1
• Qwen3 0.6B — generates thinking by default; tags are stripped when isThinking: false.

Enable it with isThinking: true on the matching ModelType.

Handling thinking responses#

The model emits a ThinkingResponse (with response.content) for its reasoning, alongside regular TextResponse tokens for the final answer:

chat.generateChatResponseAsync().listen((response) {
  if (response is ThinkingResponse) {
    // Model's reasoning process
    print('Thinking: ${response.content}');
    _showThinkingBubble(response.content);
  } else if (response is TextResponse) {
    // The final answer
    print('Text token: ${response.token}');
  }
});

You can also create a thinking message manually:

final thinkingMessage = Message.thinking(text: "Let me analyze this problem...");

Platform support#

Advanced: ModelThinkingFilter#

For custom inference implementations, ModelThinkingFilter cleans model outputs — removing model-specific tokens. This is handled automatically by the chat API, but is available if you need it:

import 'package:flutter_gemma/core/extensions.dart';

String cleanedResponse = ModelThinkingFilter.cleanResponse(
  rawResponse,
  ModelType.deepSeek,
);

// The filter removes model-specific tokens like:
// - <end_of_turn> tags (Gemma models)
// - <think>...</think> blocks (DeepSeek)
// - <|channel>thought\n...<channel|> blocks (Gemma 4 E2B/E4B)
// - extra whitespace and formatting