fix(openai): include responses instructions in captured prompt (#1565)

Co-authored-by: Hassieb Pakzad <68423100+hassiebp@users.noreply.github.com>

Author: D-Joey-G

langfuse/openai.py

@@ -246,6 +246,34 @@ def wrapper(wrapped: Any, instance: Any, args: Any, kwargs: Any) -> Any:
     return _with_langfuse
 
 
+def _extract_responses_prompt(kwargs: Any) -> Any:
+    input_value = kwargs.get("input", None)
+    instructions = kwargs.get("instructions", None)
+
+    if isinstance(input_value, NotGiven):
+        input_value = None
+
+    if isinstance(instructions, NotGiven):
+        instructions = None
+
+    if instructions is None:
+        return input_value
+
+    if input_value is None:
+        return {"instructions": instructions}
+
+    if isinstance(input_value, str):
+        return [
+            {"role": "system", "content": instructions},
+            {"role": "user", "content": input_value},
+        ]
+
+    if isinstance(input_value, list):
+        return [{"role": "system", "content": instructions}, *input_value]
+
+    return {"instructions": instructions, "input": input_value}
+
+
 def _extract_chat_prompt(kwargs: Any) -> Any:
     """Extracts the user input from prompts. Returns an array of messages or dict with messages and functions"""
     prompt = {}
@@ -403,7 +431,7 @@ def _get_langfuse_data_from_kwargs(resource: OpenAiDefinition, kwargs: Any) -> A
     if resource.type == "completion":
         prompt = kwargs.get("prompt", None)
     elif resource.object == "Responses" or resource.object == "AsyncResponses":
-        prompt = kwargs.get("input", None)
+        prompt = _extract_responses_prompt(kwargs)
     elif resource.type == "chat":
         prompt = _extract_chat_prompt(kwargs)
     elif resource.type == "embedding":

tests/test_openai.py

@@ -1407,7 +1407,10 @@ def test_response_api_streaming(openai):
     assert len(generation.data) != 0
     generationData = generation.data[0]
     assert generationData.name == generation_name
-    assert generation.data[0].input == "Hello!"
+    assert generation.data[0].input == [
+        {"role": "system", "content": "You are a helpful assistant."},
+        {"role": "user", "content": "Hello!"},
+    ]
     assert generationData.type == "GENERATION"
     assert "gpt-4o" in generationData.model
     assert generationData.start_time is not None

tests/test_openai_prompt_extraction.py

@@ -0,0 +1,46 @@
+import pytest
+
+try:
+    # Compatibility across OpenAI SDK versions where NOT_GIVEN export moved.
+    from openai import NOT_GIVEN
+except ImportError:
+    from openai._types import NOT_GIVEN
+
+from langfuse.openai import _extract_responses_prompt
+
+
+@pytest.mark.parametrize(
+    "kwargs, expected",
+    [
+        ({"input": "Hello!"}, "Hello!"),
+        (
+            {"instructions": "You are helpful.", "input": "Hello!"},
+            [
+                {"role": "system", "content": "You are helpful."},
+                {"role": "user", "content": "Hello!"},
+            ],
+        ),
+        (
+            {
+                "instructions": "You are helpful.",
+                "input": [{"role": "user", "content": "Hello!"}],
+            },
+            [
+                {"role": "system", "content": "You are helpful."},
+                {"role": "user", "content": "Hello!"},
+            ],
+        ),
+        (
+            {"instructions": "You are helpful."},
+            {"instructions": "You are helpful."},
+        ),
+        (
+            {"instructions": "You are helpful.", "input": NOT_GIVEN},
+            {"instructions": "You are helpful."},
+        ),
+        ({"instructions": NOT_GIVEN, "input": "Hello!"}, "Hello!"),
+        ({"instructions": NOT_GIVEN, "input": NOT_GIVEN}, None),
+    ],
+)
+def test_extract_responses_prompt(kwargs, expected):
+    assert _extract_responses_prompt(kwargs) == expected