Extended Thinking

// Simple configuration - uses provider defaults
final agent = Agent(
  'anthropic:claude-sonnet-4-5',
  enableThinking: true,
);

final result = await agent.send('In one sentence, how does quicksort work?');

// Access thinking via result.thinking
if (result.thinking != null) {
  print('[[${result.thinking}]]');
}
print(result.output);

final agent = Agent(
  'openai-responses:gpt-5',
  enableThinking: true,
  chatModelOptions: const OpenAIResponsesChatModelOptions(
    reasoningSummary: OpenAIReasoningSummary.brief,  // Override default
    reasoningEffort: OpenAIReasoningEffort.high,
  ),
);

final agent = Agent(
  'anthropic:claude-sonnet-4-5',
  enableThinking: true,
  chatModelOptions: const AnthropicChatOptions(
    thinkingBudgetTokens: 8192,  // Override default 4096
  ),
);

final agent = Agent(
  'google:gemini-2.5-flash',
  enableThinking: true,
  chatModelOptions: const GoogleChatModelOptions(
    thinkingBudgetTokens: 8192,  // Override dynamic default
  ),
);

// Or use explicit dynamic mode
final agentDynamic = Agent(
  'google:gemini-2.5-flash',
  enableThinking: true,
  chatModelOptions: const GoogleChatModelOptions(
    thinkingBudgetTokens: -1,  // Model decides optimal budget
  ),
);

final history = <ChatMessage>[];
var stillThinking = true;
stdout.write('[[');

await for (final chunk in agent.sendStream(
  'In one sentence: how does quicksort work?',
)) {
  // Display thinking in real-time via chunk.thinking field
  if (chunk.thinking != null) {
    stdout.write(chunk.thinking);
  }

  // Display response text
  if (chunk.output.isNotEmpty) {
    if (stillThinking) {
      stillThinking = false;
      stdout.writeln(']]\n');
    }
    stdout.write(chunk.output);
  }

  history.addAll(chunk.messages);
}

stdout.writeln('\n');