⏺ Summary of Changes

Problem Solved

AutoGen’s Anthropic client did not support thinking mode—Claude’s ability to show its reasoning process before providing a final answer.
Without this, users could not access the internal thought process that makes Claude’s responses more accurate and transparent.

Changes Made

Core Implementation (_anthropic_client.py)

• Added _get_thinking_config() method to handle thinking parameter validation.
• Added thinking content extraction for both regular and streaming responses.
• Added support for thinking parameter in API calls.
• Fixed pre-existing bug: _last_used_tools initialization.

Configuration Support (config/init.py)

• Added ThinkingConfig TypedDict and ThinkingConfigModel for type safety.
• Integrated thinking config into existing configuration structures.

Test Coverage (test_anthropic_model_client.py)

• Added 4 comprehensive tests covering validation, basic usage, streaming, and tool integration.

Key Design Decisions

• API-First Validation: Let Anthropic API handle all validation (budget_tokens, model support, temperature requirements).
• User Responsibility: Users must set temperature=1.0 themselves — no automatic overrides.
• Model-Agnostic: Works with any model name format (API validates support).
• Clean Integration: Follows AutoGen’s existing extra_create_args pattern.

⏺ Usage Example

thinking_config = {
    "thinking": {
        "type": "enabled",
        "budget_tokens": 2000
    }
}

result = await client.create(messages, extra_create_args=thinking_config)

print(result.thought)   # reasoning process
print(result.content)   # final answer

⏺ Result

AutoGen users can now access Claude’s reasoning process, leading to more transparent and explainable AI interactions, while maintaining clean, maintainable code that follows AutoGen’s architectural principles.

⏺ Related Issue

Closes #6095

⏺ Checks

• I’ve included any doc changes needed for https://microsoft.github.io/autogen/.
• I’ve added tests corresponding to the changes introduced in this PR.
• I’ve made sure all auto checks have passed.