feat(langchain): add ChatAnthropic support, including tool-calling, to langchain instrumentation

instrumentation/opentelemetry-instrumentation-genai-langchain/.changelog/188.added

@@ -0,0 +1,2 @@
+Add ChatAnthropic tool-calling test coverage and fix finish_reason extraction for 
+Anthropic responses in LangChain instrumentation.

instrumentation/opentelemetry-instrumentation-genai-langchain/src/opentelemetry/instrumentation/genai/langchain/callback_handler.py

@@ -236,12 +236,19 @@ def on_chat_model_start(
             frequency_penalty = params.get("frequency_penalty")
             presence_penalty = params.get("presence_penalty")
             stop_sequences = params.get("stop")
+            if stop_sequences is None:
+                stop_sequences = params.get("stop_sequences")
+            if stop_sequences is None:
+                serialized_kwargs: dict[str, Any] = (
+                    serialized.get("kwargs") or {}
+                )
+                stop_sequences = serialized_kwargs.get("stop_sequences")
             seed = params.get("seed")
             temperature = params.get("temperature")
-            # ``max_completion_tokens`` is OpenAI-specific; fall back to the
-            # generic ``max_tokens`` used by Anthropic, Mistral, Cohere, etc.
-            max_tokens = params.get("max_completion_tokens") or params.get(
-                "max_tokens"
+            max_tokens = (
+                params.get("max_completion_tokens")
+                if params.get("max_completion_tokens") is not None
+                else params.get("max_tokens")
             )
 
         provider = normalize_provider(metadata) or "unknown"
@@ -327,7 +334,10 @@ def on_llm_end(
                     ):
                         finish_reason = (
                             chat_generation.message.response_metadata.get(
-                                "stopReason", "unknown"
+                                "stopReason"
+                            )
+                            or chat_generation.message.response_metadata.get(
+                                "stop_reason", "unknown"
                             )
                         )
 

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/cassettes/test_chat_anthropic_claude_sonnet_llm_call.yaml

@@ -0,0 +1,46 @@
+interactions:
+- request:
+    body: |-
+      {"model": "claude-sonnet-4-5", "max_tokens": 1024, "temperature": 0.1, "system": "You are a helpful assistant!", "messages": [{"role": "user", "content": "What is the capital of France?"}]}
+    headers:
+      Content-Type:
+      - application/json
+      User-Agent:
+      - !!binary |
+        QW50aHJvcGljL1B5dGhvbiAxLjAuMA==
+      x-api-key:
+      - test_key
+      anthropic-version:
+      - '2023-06-01'
+    method: POST
+    uri: https://api.anthropic.com/v1/messages
+  response:
+    body:
+      string: |-
+        {
+          "id": "msg_01XFDUDYJgAACzvnptvVoYEL",
+          "type": "message",
+          "role": "assistant",
+          "model": "claude-sonnet-4-5",
+          "content": [
+            {
+              "type": "text",
+              "text": "The capital of France is Paris."
+            }
+          ],
+          "stop_reason": "end_turn",
+          "stop_sequence": null,
+          "usage": {
+            "input_tokens": 13,
+            "output_tokens": 10
+          }
+        }
+    headers:
+      Content-Type:
+      - application/json
+      Date:
+      - Thu, 04 Sep 2025 20:00:58 GMT
+    status:
+      code: 200
+      message: OK
+version: 1

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/cassettes/test_chat_anthropic_claude_sonnet_stop_sequences_constructor_fallback.yaml

@@ -0,0 +1,44 @@
+# TODO: this is generated by AI, re-record
+interactions:
+- request:
+    body: |-
+      {"max_tokens":1024,"messages":[{"role":"user","content":"Say hi"}],"model":"claude-sonnet-4-5","stop_sequences":["STOP"]}
+    headers:
+      Content-Type:
+      - application/json
+      x-api-key:
+      - test_key
+      anthropic-version:
+      - '2023-06-01'
+    method: POST
+    uri: https://api.anthropic.com/v1/messages
+  response:
+    body:
+      string: |-
+        {
+          "id": "msg_anthropic_constructor_stop_sequences_001",
+          "type": "message",
+          "role": "assistant",
+          "model": "claude-sonnet-4-5",
+          "content": [
+            {
+              "type": "text",
+              "text": "Hi there!"
+            }
+          ],
+          "stop_reason": "stop_sequence",
+          "stop_sequence": "STOP",
+          "usage": {
+            "input_tokens": 10,
+            "output_tokens": 5
+          }
+        }
+    headers:
+      Content-Type:
+      - application/json
+      Date:
+      - Thu, 04 Sep 2025 20:00:58 GMT
+    status:
+      code: 200
+      message: OK
+version: 1

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/cassettes/test_chat_anthropic_claude_sonnet_stop_sequences_fallback.yaml

@@ -0,0 +1,55 @@
+# TODO: this is generated by AI, re-record
+interactions:
+- request:
+    body: |-
+      {
+        "model": "claude-sonnet-4-5",
+        "max_tokens": 1024,
+        "temperature": 0.1,
+        "stop_sequences": ["STOP"],
+        "messages": [
+          {
+            "role": "user",
+            "content": "Say hi"
+          }
+        ]
+      }
+    headers:
+      Content-Type:
+      - application/json
+      x-api-key:
+      - test_key
+      anthropic-version:
+      - '2023-06-01'
+    method: POST
+    uri: https://api.anthropic.com/v1/messages
+  response:
+    body:
+      string: |-
+        {
+          "id": "msg_anthropic_stop_sequences_001",
+          "type": "message",
+          "role": "assistant",
+          "model": "claude-sonnet-4-5",
+          "content": [
+            {
+              "type": "text",
+              "text": "Hi there!"
+            }
+          ],
+          "stop_reason": "stop_sequence",
+          "stop_sequence": "STOP",
+          "usage": {
+            "input_tokens": 10,
+            "output_tokens": 5
+          }
+        }
+    headers:
+      Content-Type:
+      - application/json
+      Date:
+      - Thu, 04 Sep 2025 20:00:58 GMT
+    status:
+      code: 200
+      message: OK
+version: 1

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/cassettes/test_chat_anthropic_claude_sonnet_tool_call.yaml

@@ -0,0 +1,48 @@
+# TODO: this is generated by AI, re-record
+interactions:
+- request:
+    body: |-
+      {"model":"claude-sonnet-4-5","max_tokens":1024,"messages":[{"role":"user","content":"What's the weather in Seattle?"}],"temperature":0.1,"tools":[{"name":"get_current_weather","input_schema":{"properties":{"location":{"type":"string"}},"required":["location"],"type":"object"},"description":"Get the current weather in a given location."}]}
+    headers:
+      Content-Type:
+      - application/json
+      x-api-key:
+      - test_key
+      anthropic-version:
+      - '2023-06-01'
+    method: POST
+    uri: https://api.anthropic.com/v1/messages
+  response:
+    body:
+      string: |-
+        {
+          "id": "msg_anthropic_tool_call_001",
+          "type": "message",
+          "role": "assistant",
+          "model": "claude-sonnet-4-5",
+          "content": [
+            {
+              "type": "tool_use",
+              "id": "toolu_01",
+              "name": "get_current_weather",
+              "input": {
+                "location": "Seattle, WA"
+              }
+            }
+          ],
+          "stop_reason": "tool_use",
+          "stop_sequence": null,
+          "usage": {
+            "input_tokens": 20,
+            "output_tokens": 15
+          }
+        }
+    headers:
+      Content-Type:
+      - application/json
+      Date:
+      - Thu, 04 Sep 2025 20:00:58 GMT
+    status:
+      code: 200
+      message: OK
+version: 1

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

@@ -7,6 +7,7 @@
 
 import boto3
 import pytest
+from langchain_anthropic import ChatAnthropic
 from langchain_aws import ChatBedrock
 from langchain_google_genai import ChatGoogleGenerativeAI
 from langchain_openai import ChatOpenAI
@@ -65,6 +66,18 @@ def fixture_us_amazon_nova_lite_v1_0():
     yield llm
 
 
+@pytest.fixture(scope="function", name="chat_anthropic_claude_sonnet")
+def fixture_chat_anthropic_claude_sonnet():
+    llm_model_value = "claude-sonnet-4-5"
+    llm = ChatAnthropic(
+        model=llm_model_value,
+        api_key="test_key",
+        temperature=0.1,
+        max_tokens=1024,
+    )
+    yield llm
+
+
 @pytest.fixture(scope="function", name="gemini")
 def fixture_gemini():
     llm_model_value = "gemini-2.5-pro"

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/requirements.latest.txt

@@ -18,7 +18,8 @@ langchain==1.3.14
 langchain-openai==1.3.5
 langchain-aws==1.6.2
 langchain-google-genai==4.2.7
+langchain-anthropic==1.4.8
 boto3==1.43.53
 
 -e util/opentelemetry-util-genai
--e instrumentation/opentelemetry-instrumentation-genai-langchain[instruments]
+-e instrumentation/opentelemetry-instrumentation-genai-langchain[instruments]

instrumentation/opentelemetry-instrumentation-genai-langchain/tests/requirements.oldest.txt

@@ -23,4 +23,5 @@
 langchain-openai==0.2.0
 langchain-aws==0.2.2
 langchain-google-genai==2.0.0
-boto3==1.37.0
+langchain-anthropic==0.3.0
+boto3==1.37.0