fix(langchain): include content attribute when assistant messages have tool calls

.github/workflows/ci.yml

@@ -26,6 +26,15 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Free up disk space
+        run: |
+          sudo apt-get remove -y '^dotnet-.*' '^llvm-.*' 'php.*' '^mongodb-.*' '^mysql-.*' azure-cli google-cloud-cli google-chrome-stable firefox powershell mono-devel libgl1-mesa-dri || true
+          sudo apt-get autoremove -y
+          sudo apt-get clean
+          # Remove Docker images
+          docker rmi $(docker images -aq) || true
+          # Show available space
+          df -h
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
@@ -55,6 +64,15 @@ jobs:
         python-version: ["3.11"]
 
     steps:
+      - name: Free up disk space
+        run: |
+          sudo apt-get remove -y '^dotnet-.*' '^llvm-.*' 'php.*' '^mongodb-.*' '^mysql-.*' azure-cli google-cloud-cli google-chrome-stable firefox powershell mono-devel libgl1-mesa-dri || true
+          sudo apt-get autoremove -y
+          sudo apt-get clean
+          # Remove Docker images
+          docker rmi $(docker images -aq) || true
+          # Show available space
+          df -h
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
@@ -91,6 +109,15 @@ jobs:
         python-version: ["3.10", "3.11", "3.12"]
 
     steps:
+      - name: Free up disk space
+        run: |
+          sudo apt-get remove -y '^dotnet-.*' '^llvm-.*' 'php.*' '^mongodb-.*' '^mysql-.*' azure-cli google-cloud-cli google-chrome-stable firefox powershell mono-devel libgl1-mesa-dri || true
+          sudo apt-get autoremove -y
+          sudo apt-get clean
+          # Remove Docker images
+          docker rmi $(docker images -aq) || true
+          # Show available space
+          df -h
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0

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

@@ -176,17 +176,17 @@ def set_chat_request(
                         span, f"{SpanAttributes.LLM_PROMPTS}.{i}", tool_calls
                     )
 
-                else:
-                    content = (
-                        msg.content
-                        if isinstance(msg.content, str)
-                        else json.dumps(msg.content, cls=CallbackFilteredJSONEncoder)
-                    )
-                    _set_span_attribute(
-                        span,
-                        f"{SpanAttributes.LLM_PROMPTS}.{i}.content",
-                        content,
-                    )
+                # Always set content if it exists, regardless of tool_calls presence
+                content = (
+                    msg.content
+                    if isinstance(msg.content, str)
+                    else json.dumps(msg.content, cls=CallbackFilteredJSONEncoder)
+                )
+                _set_span_attribute(
+                    span,
+                    f"{SpanAttributes.LLM_PROMPTS}.{i}.content",
+                    content,
+                )
 
                 if msg.type == "tool" and hasattr(msg, "tool_call_id"):
                     _set_span_attribute(

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

@@ -144,8 +144,6 @@ def environment():
         os.environ["COHERE_API_KEY"] = "test"
     if not os.environ.get("TAVILY_API_KEY"):
         os.environ["TAVILY_API_KEY"] = "test"
-    if not os.environ.get("LANGSMITH_API_KEY"):
-        os.environ["LANGSMITH_API_KEY"] = "test"
 
 
 @pytest.fixture(scope="module")

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

@@ -1,10 +1,9 @@
-import os
 from typing import Tuple
 
 import pytest
-from langchain import hub
 from langchain.agents import AgentExecutor, create_tool_calling_agent
 from langchain_community.tools.tavily_search import TavilySearchResults
+from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
 from langchain_openai import ChatOpenAI
 from opentelemetry.sdk._logs import LogData
 from opentelemetry.semconv._incubating.attributes import (
@@ -14,6 +13,16 @@
     gen_ai_attributes as GenAIAttributes,
 )
 
+# Constant prompt template to replace hub.pull("hwchase17/openai-functions-agent")
+OPENAI_FUNCTIONS_AGENT_PROMPT = ChatPromptTemplate.from_messages(
+    [
+        ("system", "You are a helpful assistant"),
+        MessagesPlaceholder("chat_history", optional=True),
+        ("human", "{input}"),
+        MessagesPlaceholder("agent_scratchpad"),
+    ]
+)
+
 
 @pytest.mark.vcr
 def test_agents(instrument_legacy, span_exporter, log_exporter):
@@ -22,10 +31,7 @@ def test_agents(instrument_legacy, span_exporter, log_exporter):
 
     model = ChatOpenAI(model="gpt-3.5-turbo")
 
-    prompt = hub.pull(
-        "hwchase17/openai-functions-agent",
-        api_key=os.environ["LANGSMITH_API_KEY"],
-    )
+    prompt = OPENAI_FUNCTIONS_AGENT_PROMPT
 
     agent = create_tool_calling_agent(model, tools, prompt)
     agent_executor = AgentExecutor(agent=agent, tools=tools)
@@ -68,10 +74,7 @@ def test_agents_with_events_with_content(
 
     model = ChatOpenAI(model="gpt-3.5-turbo")
 
-    prompt = hub.pull(
-        "hwchase17/openai-functions-agent",
-        api_key=os.environ["LANGSMITH_API_KEY"],
-    )
+    prompt = OPENAI_FUNCTIONS_AGENT_PROMPT
 
     agent = create_tool_calling_agent(model, tools, prompt)
     agent_executor = AgentExecutor(agent=agent, tools=tools)
@@ -166,10 +169,7 @@ def test_agents_with_events_with_no_content(
 
     model = ChatOpenAI(model="gpt-3.5-turbo")
 
-    prompt = hub.pull(
-        "hwchase17/openai-functions-agent",
-        api_key=os.environ["LANGSMITH_API_KEY"],
-    )
+    prompt = OPENAI_FUNCTIONS_AGENT_PROMPT
 
     agent = create_tool_calling_agent(model, tools, prompt)
     agent_executor = AgentExecutor(agent=agent, tools=tools)

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

@@ -0,0 +1,160 @@
+"""
+Test for the fix of the issue where assistant message content is missing
+when tool calls are present in LangGraph/LangChain instrumentation.
+
+This test reproduces the issue reported in GitHub where gen_ai.prompt.X.content
+attributes were missing for assistant messages that contained tool_calls.
+"""
+
+from unittest.mock import Mock
+from langchain_core.messages import AIMessage, HumanMessage, ToolMessage
+from opentelemetry.instrumentation.langchain.span_utils import set_chat_request
+from opentelemetry.semconv_ai import SpanAttributes
+
+
+def test_assistant_message_with_tool_calls_includes_content():
+    """
+    Test that when an assistant message has both content and tool_calls,
+    both the content and tool_calls are included in the span attributes.
+
+    This addresses the issue where content was missing when tool_calls were present.
+    """
+    mock_span = Mock()
+    mock_span.set_attribute = Mock()
+    mock_span_holder = Mock()
+    mock_span_holder.request_model = None
+    messages = [
+        [
+            HumanMessage(content="what is the current time? First greet me."),
+            AIMessage(
+                content="Hello! Let me check the current time for you.",
+                tool_calls=[
+                    {
+                        "id": "call_qU7pH3EdQvzwkPyKPOdpgaKA",
+                        "name": "get_current_time",
+                        "args": {},
+                    }
+                ],
+            ),
+            ToolMessage(
+                content="2025-08-15 08:15:21",
+                tool_call_id="call_qU7pH3EdQvzwkPyKPOdpgaKA",
+            ),
+            AIMessage(content="The current time is 2025-08-15 08:15:21"),
+        ]
+    ]
+
+    set_chat_request(mock_span, {}, messages, {}, mock_span_holder)
+
+    call_args = [call[0] for call in mock_span.set_attribute.call_args_list]
+    attributes = {args[0]: args[1] for args in call_args}
+
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.0.role"] == "user"
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.content" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.0.content"]
+        == "what is the current time? First greet me."
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.1.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.1.role"] == "assistant"
+    assert f"{SpanAttributes.LLM_PROMPTS}.1.content" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.1.content"]
+        == "Hello! Let me check the current time for you."
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.1.tool_calls.0.id" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.1.tool_calls.0.id"]
+        == "call_qU7pH3EdQvzwkPyKPOdpgaKA"
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.1.tool_calls.0.name" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.1.tool_calls.0.name"]
+        == "get_current_time"
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.2.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.2.role"] == "tool"
+    assert f"{SpanAttributes.LLM_PROMPTS}.2.content" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.2.content"] == "2025-08-15 08:15:21"
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.2.tool_call_id" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.2.tool_call_id"]
+        == "call_qU7pH3EdQvzwkPyKPOdpgaKA"
+    )
+    assert f"{SpanAttributes.LLM_PROMPTS}.3.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.3.role"] == "assistant"
+    assert f"{SpanAttributes.LLM_PROMPTS}.3.content" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.3.content"]
+        == "The current time is 2025-08-15 08:15:21"
+    )
+
+
+def test_assistant_message_with_only_tool_calls_no_content():
+    """
+    Test that when an assistant message has only tool_calls and no content,
+    the tool_calls are still included and no content attribute is set.
+    """
+    mock_span = Mock()
+    mock_span.set_attribute = Mock()
+    mock_span_holder = Mock()
+    mock_span_holder.request_model = None
+
+    messages = [
+        [
+            AIMessage(
+                content="",
+                tool_calls=[
+                    {"id": "call_123", "name": "some_tool", "args": {"param": "value"}}
+                ],
+            )
+        ]
+    ]
+
+    set_chat_request(mock_span, {}, messages, {}, mock_span_holder)
+
+    call_args = [call[0] for call in mock_span.set_attribute.call_args_list]
+    attributes = {args[0]: args[1] for args in call_args}
+
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.0.role"] == "assistant"
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.content" not in attributes
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.tool_calls.0.id" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.0.tool_calls.0.id"] == "call_123"
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.tool_calls.0.name" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.0.tool_calls.0.name"] == "some_tool"
+    )
+
+
+def test_assistant_message_with_only_content_no_tool_calls():
+    """
+    Test that when an assistant message has only content and no tool_calls,
+    the content is included and no tool_calls attributes are set.
+    """
+    mock_span = Mock()
+    mock_span.set_attribute = Mock()
+    mock_span_holder = Mock()
+    mock_span_holder.request_model = None
+
+    messages = [[AIMessage(content="Just a regular response with no tool calls")]]
+
+    set_chat_request(mock_span, {}, messages, {}, mock_span_holder)
+
+    call_args = [call[0] for call in mock_span.set_attribute.call_args_list]
+
+    attributes = {args[0]: args[1] for args in call_args}
+
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.role" in attributes
+    assert attributes[f"{SpanAttributes.LLM_PROMPTS}.0.role"] == "assistant"
+    assert f"{SpanAttributes.LLM_PROMPTS}.0.content" in attributes
+    assert (
+        attributes[f"{SpanAttributes.LLM_PROMPTS}.0.content"]
+        == "Just a regular response with no tool calls"
+    )
+
+    tool_call_attributes = [attr for attr in attributes.keys() if "tool_calls" in attr]
+    assert len(tool_call_attributes) == 0