fix(fireworks): Properly handle reasoning content.

src/any_llm/providers/fireworks/fireworks.py

@@ -4,9 +4,10 @@
 from openai import AsyncStream
 
 from any_llm.providers.openai.base import BaseOpenAIProvider
-from any_llm.types.completion import Reasoning
 from any_llm.types.responses import Response, ResponsesParams, ResponseStreamEvent
 
+from .utils import extract_reasoning_from_response
+
 
 class FireworksProvider(BaseOpenAIProvider):
     PROVIDER_NAME = "fireworks"
@@ -27,13 +28,6 @@ async def _aresponses(
     ) -> Response | AsyncIterator[ResponseStreamEvent]:
         """Call Fireworks Responses API and normalize into ChatCompletion/Chunks."""
         response = await super()._aresponses(params, **kwargs)
-
         if isinstance(response, Response) and not isinstance(response, AsyncStream):
-            # See https://fireworks.ai/blog/response-api for details about Fireworks Responses API support
-            reasoning = response.output[-1].content[0].text.split("</think>")[-1]  # type: ignore[union-attr,index]
-            if reasoning:
-                reasoning = reasoning.strip()
-                response.output[-1].content[0].text = response.output[-1].content[0].text.split("</think>")[0]  # type: ignore[union-attr,index]
-            response.reasoning = Reasoning(content=reasoning) if reasoning else None  # type: ignore[assignment]
-
+            return extract_reasoning_from_response(response)
         return response

src/any_llm/providers/fireworks/utils.py

@@ -0,0 +1,29 @@
+# mypy: disable-error-code="union-attr"
+from any_llm.types.completion import Reasoning
+from any_llm.types.responses import Response
+
+
+def extract_reasoning_from_response(response: Response) -> Response:
+    """Extract <think> content from Fireworks response and set reasoning field.
+
+    Fireworks Responses API includes reasoning content within <think></think> tags.
+    This function extracts that content and moves it to the reasoning field.
+
+    Args:
+        response: The Response object to process
+
+    Returns:
+        The modified Response object with reasoning extracted
+    """
+    if not response.output or not response.output[-1].content:
+        return response
+
+    content_text = response.output[-1].content[0].text
+    if "<think>" in content_text and "</think>" in content_text:
+        reasoning = content_text.split("<think>")[1].split("</think>")[0].strip()
+        # Skip case where reasoning is empty but tags are present
+        if reasoning:
+            response.reasoning = Reasoning(content=reasoning)  # type: ignore[assignment]
+        response.output[-1].content[0].text = content_text.split("</think>")[1].strip()
+
+    return response

tests/unit/providers/test_fireworks_provider.py

@@ -0,0 +1,74 @@
+from unittest.mock import Mock
+
+from any_llm.providers.fireworks.utils import extract_reasoning_from_response
+from any_llm.types.completion import Reasoning
+from any_llm.types.responses import Response
+
+
+def test_extract_reasoning_from_response_with_think_tags() -> None:
+    """Test that <think> content is correctly extracted into reasoning field."""
+    # Create a mock Response with <think> tags in content
+    mock_content = Mock()
+    mock_content.text = "<think>This is my reasoning process</think>This is the actual response"
+
+    mock_output_item = Mock()
+    mock_output_item.content = [mock_content]
+
+    mock_response = Mock(spec=Response)
+    mock_response.output = [mock_output_item]
+    mock_response.reasoning = None
+
+    result = extract_reasoning_from_response(mock_response)
+
+    assert result.reasoning is not None
+    assert isinstance(result.reasoning, Reasoning)
+    assert result.reasoning.content == "This is my reasoning process"
+    assert mock_content.text == "This is the actual response"
+
+
+def test_extract_reasoning_from_response_without_think_tags() -> None:
+    """Test that responses without <think> tags are returned unchanged."""
+    mock_content = Mock()
+    mock_content.text = "This is just a regular response"
+
+    mock_output_item = Mock()
+    mock_output_item.content = [mock_content]
+
+    mock_response = Mock(spec=Response)
+    mock_response.output = [mock_output_item]
+    mock_response.reasoning = None
+
+    result = extract_reasoning_from_response(mock_response)
+
+    assert result.reasoning is None
+    assert mock_content.text == "This is just a regular response"
+
+
+def test_extract_reasoning_from_response_empty_reasoning() -> None:
+    """Test that empty reasoning content is handled correctly."""
+    mock_content = Mock()
+    mock_content.text = "<think></think>This is the actual response"
+
+    mock_output_item = Mock()
+    mock_output_item.content = [mock_content]
+
+    mock_response = Mock(spec=Response)
+    mock_response.output = [mock_output_item]
+    mock_response.reasoning = None
+
+    result = extract_reasoning_from_response(mock_response)
+
+    assert result.reasoning is None
+    assert mock_content.text == "This is the actual response"
+
+
+def test_extract_reasoning_from_response_empty_output() -> None:
+    """Test that responses with empty output are handled gracefully."""
+    mock_response = Mock(spec=Response)
+    mock_response.output = []
+    mock_response.reasoning = None
+
+    result = extract_reasoning_from_response(mock_response)
+
+    assert result.reasoning is None
+    assert result == mock_response