fix(langchain): incorrect role on generations

packages/opentelemetry-instrumentation-langchain/opentelemetry/instrumentation/langchain/span_utils.py

@@ -211,11 +211,6 @@ def set_chat_response(span: Span, response: LLMResult) -> None:
     for generations in response.generations:
         for generation in generations:
             prefix = f"{GenAIAttributes.GEN_AI_COMPLETION}.{i}"
-            _set_span_attribute(
-                span,
-                f"{prefix}.role",
-                _message_type_to_role(generation.type),
-            )
 
             # Try to get content from various sources
             content = None
@@ -244,6 +239,11 @@ def set_chat_response(span: Span, response: LLMResult) -> None:
 
             # Handle tool calls and function calls
             if hasattr(generation, "message") and generation.message:
+                _set_span_attribute(
+                    span,
+                    f"{prefix}.role",
+                    _message_type_to_role(generation.message.type),
+                )
                 # Handle legacy function_call format (single function call)
                 if generation.message.additional_kwargs.get("function_call"):
                     _set_span_attribute(
@@ -268,12 +268,11 @@ def set_chat_response(span: Span, response: LLMResult) -> None:
                     else generation.message.additional_kwargs.get("tool_calls")
                 )
                 if tool_calls and isinstance(tool_calls, list):
-                    _set_span_attribute(
-                        span,
-                        f"{prefix}.role",
-                        "assistant",
-                    )
                     _set_chat_tool_calls(span, prefix, tool_calls)
+            else:
+                _set_span_attribute(
+                    span, f"{prefix}.role", "assistant"
+                )
             i += 1
 
 

packages/opentelemetry-instrumentation-langchain/tests/test_span_utils.py

@@ -0,0 +1,86 @@
+import json
+
+import pytest
+from langchain_core.messages import AIMessage
+from langchain_core.outputs import ChatGeneration, Generation, LLMResult
+
+from opentelemetry.instrumentation.langchain.span_utils import set_chat_response
+from opentelemetry.instrumentation.langchain.utils import TRACELOOP_TRACE_CONTENT
+from opentelemetry.semconv._incubating.attributes import (
+    gen_ai_attributes as GenAIAttributes,
+)
+
+
+class _DummySpan:
+    def __init__(self):
+        self.attributes = {}
+
+    def is_recording(self) -> bool:
+        return True
+
+    def set_attribute(self, key, value) -> None:
+        self.attributes[key] = value
+
+
+@pytest.fixture(autouse=True)
+def _enable_prompt_content(monkeypatch):
+    monkeypatch.setenv(TRACELOOP_TRACE_CONTENT, "true")
+
+
+def _make_result(message: AIMessage) -> tuple[_DummySpan, LLMResult]:
+    span = _DummySpan()
+    generation = ChatGeneration(message=message)
+    result = LLMResult(generations=[[generation]])
+    return span, result
+
+
+@pytest.mark.parametrize(
+    "message",
+    [
+        AIMessage(content="hi"),
+        AIMessage(
+            content="tool reply",
+            additional_kwargs={
+                "function_call": {"name": "call_weather", "arguments": "{}"}
+            },
+        ),
+        AIMessage(
+            content="another reply",
+            tool_calls=[{"name": "foo", "args": {"city": "SF"}, "id": "1"}],
+        ),
+    ],
+)
+def test_chat_generation_role_is_assistant(message):
+    span, result = _make_result(message)
+
+    set_chat_response(span, result)
+
+    assert (
+        span.attributes[f"{GenAIAttributes.GEN_AI_COMPLETION}.0.role"]
+        == "assistant"
+    )
+
+    tool_call = message.additional_kwargs.get("function_call")
+    if tool_call:
+        prefix = f"{GenAIAttributes.GEN_AI_COMPLETION}.0.tool_calls.0"
+        assert span.attributes[prefix + ".name"] == tool_call["name"]
+        assert span.attributes[prefix + ".arguments"] == tool_call["arguments"]
+
+    if message.tool_calls:
+        prefix = f"{GenAIAttributes.GEN_AI_COMPLETION}.0.tool_calls.0"
+        assert span.attributes[prefix + ".name"] == message.tool_calls[0]["name"]
+        assert span.attributes[prefix + ".id"] == message.tool_calls[0]["id"]
+        recorded_args = json.loads(span.attributes[prefix + ".arguments"])
+        assert recorded_args == message.tool_calls[0]["args"]
+
+
+def test_plain_generation_defaults_to_assistant_role():
+    span = _DummySpan()
+    generation = Generation(text="plain completion")
+    result = LLMResult(generations=[[generation]])
+
+    set_chat_response(span, result)
+
+    prefix = f"{GenAIAttributes.GEN_AI_COMPLETION}.0"
+    assert span.attributes[prefix + ".role"] == "assistant"
+    assert span.attributes[prefix + ".content"] == "plain completion"