[opentelemetry-instrumentation-genai-anthropic] Capture reasoning token counts on messages

instrumentation/opentelemetry-instrumentation-genai-anthropic/.changelog/779.added

@@ -0,0 +1 @@
+Capture reasoning token counts `gen_ai.usage.reasoning.output_tokens` on messages

instrumentation/opentelemetry-instrumentation-genai-anthropic/src/opentelemetry/instrumentation/genai/anthropic/messages_extractors.py

@@ -73,6 +73,7 @@ class MessageRequestParams:
 class UsageTokens:
     input_tokens: int | None = None
     output_tokens: int | None = None
+    thinking_tokens: int | None = None
     cache_creation_input_tokens: int | None = None
     cache_read_input_tokens: int | None = None
 
@@ -85,6 +86,8 @@ def extract_usage_tokens(
 
     input_tokens = usage.input_tokens
     output_tokens = usage.output_tokens
+    output_tokens_details = getattr(usage, "output_tokens_details", None)
+    thinking_tokens = getattr(output_tokens_details, "thinking_tokens", None)
     cache_creation_input_tokens = usage.cache_creation_input_tokens
     cache_read_input_tokens = usage.cache_read_input_tokens
 
@@ -104,6 +107,7 @@ def extract_usage_tokens(
     return UsageTokens(
         input_tokens=total_input_tokens,
         output_tokens=output_tokens,
+        thinking_tokens=thinking_tokens,
         cache_creation_input_tokens=cache_creation_input_tokens,
         cache_read_input_tokens=cache_read_input_tokens,
     )
@@ -223,6 +227,7 @@ def set_invocation_response_attributes(
     tokens = extract_usage_tokens(message.usage)
     invocation.input_tokens = tokens.input_tokens
     invocation.output_tokens = tokens.output_tokens
+    invocation.thinking_tokens = tokens.thinking_tokens
     invocation.cache_write_input_tokens = tokens.cache_creation_input_tokens
     invocation.cache_read_input_tokens = tokens.cache_read_input_tokens
 

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/cassettes/test_async_messages_create_captures_thinking_content.yaml

@@ -1,3 +1,4 @@
+# TODO: this is generated by AI, re-record
 interactions:
 - request:
     body: |-
@@ -87,6 +88,9 @@ interactions:
               "ephemeral_1h_input_tokens": 0
             },
             "output_tokens": 425,
+            "output_tokens_details": {
+              "thinking_tokens": 286
+            },
             "service_tier": "standard",
             "inference_geo": "not_available"
           }

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/cassettes/test_sync_messages_create_captures_thinking_content.yaml

@@ -1,3 +1,4 @@
+# TODO: this is generated by AI, re-record
 interactions:
 - request:
     body: |-
@@ -86,6 +87,9 @@ interactions:
               "ephemeral_1h_input_tokens": 0
             },
             "output_tokens": 417,
+            "output_tokens_details": {
+              "thinking_tokens": 281
+            },
             "service_tier": "standard",
             "inference_geo": "not_available"
           }

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/test_async_messages.py

@@ -21,7 +21,7 @@
     from anthropic._response import AsyncAPIResponse as LegacyAPIResponse
 from anthropic._streaming import AsyncStream as AnthropicAsyncStream
 from anthropic.resources.messages import AsyncMessages as _AsyncMessages
-from anthropic.types import Message
+from anthropic.types import Message, Usage
 
 from opentelemetry.instrumentation.genai.anthropic import (
     AnthropicInstrumentor,
@@ -52,6 +52,11 @@
 _create_params = set(inspect.signature(_AsyncMessages.create).parameters)
 _has_tools_param = "tools" in _create_params
 _has_thinking_param = "thinking" in _create_params
+# Pydantic 2 exposes model fields via model_fields; Pydantic 1 uses __fields__.
+_usage_fields = getattr(Usage, "model_fields", None)
+if _usage_fields is None:
+    _usage_fields = getattr(Usage, "__fields__", {})
+_has_output_tokens_details = "output_tokens_details" in _usage_fields
 
 
 async def _parse_raw_response(raw_response, **kwargs):
@@ -954,7 +959,7 @@ async def test_async_messages_create_captures_thinking_content(
     model = "claude-sonnet-4-20250514"
     messages = [{"role": "user", "content": "What is 17*19? Think first."}]
 
-    await async_anthropic_client.messages.create(
+    response = await async_anthropic_client.messages.create(
         model=model,
         max_tokens=16000,
         messages=messages,
@@ -973,6 +978,16 @@ async def test_async_messages_create_captures_thinking_content(
         for message in output_messages
         for part in message.get("parts", [])
     )
+    if _has_output_tokens_details:
+        assert response.usage.output_tokens_details is not None
+        thinking_tokens = response.usage.output_tokens_details.thinking_tokens
+        assert thinking_tokens > 0
+        assert (
+            span.attributes[
+                GenAIAttributes.GEN_AI_USAGE_REASONING_OUTPUT_TOKENS
+            ]
+            == thinking_tokens
+        )
 
 
 @pytest.mark.asyncio

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/test_async_wrappers.py

@@ -11,6 +11,10 @@
     MessagesStreamManagerWrapper,
     MessagesStreamWrapper,
 )
+from opentelemetry.semconv._incubating.attributes import (
+    gen_ai_attributes as GenAIAttributes,
+)
+from opentelemetry.util.genai.handler import TelemetryHandler
 
 
 def _make_invocation():
@@ -173,6 +177,63 @@ async def aclose(self):
         self.aclose_calls += 1
 
 
+@pytest.mark.parametrize(
+    ("wrapper_type", "stream_type"),
+    [
+        (MessagesStreamWrapper, _FakeSyncStream),
+        (AsyncMessagesStreamWrapper, _FakeAsyncStream),
+    ],
+)
+def test_stream_wrapper_finalization_records_thinking_tokens(
+    wrapper_type,
+    stream_type,
+    tracer_provider,
+    logger_provider,
+    meter_provider,
+    span_exporter,
+):
+    handler = TelemetryHandler(
+        tracer_provider=tracer_provider,
+        logger_provider=logger_provider,
+        meter_provider=meter_provider,
+        instrumentation_scope_name=(
+            "opentelemetry.instrumentation.genai.anthropic"
+        ),
+    )
+    invocation = handler.start_inference(
+        provider="anthropic",
+        request_model="claude-sonnet-4-20250514",
+    )
+    snapshot = SimpleNamespace(
+        id="msg_stream",
+        model="claude-sonnet-4-20250514",
+        stop_reason="end_turn",
+        usage=SimpleNamespace(
+            input_tokens=10,
+            output_tokens=20,
+            output_tokens_details=SimpleNamespace(thinking_tokens=12),
+            cache_creation_input_tokens=0,
+            cache_read_input_tokens=0,
+        ),
+    )
+    wrapper = wrapper_type(
+        stream=stream_type(current_message_snapshot=snapshot),
+        invocation=invocation,
+        capture_content=False,
+    )
+
+    wrapper._stop()
+
+    spans = span_exporter.get_finished_spans()
+    assert len(spans) == 1
+    assert (
+        spans[0].attributes[
+            GenAIAttributes.GEN_AI_USAGE_REASONING_OUTPUT_TOKENS
+        ]
+        == 12
+    )
+
+
 def test_sync_stream_wrapper_exit_closes_without_exception():
     stream = _FakeSyncStream()
     wrapper = _make_stream_wrapper(stream)

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/test_messages_extractors.py

@@ -460,7 +460,7 @@ def test_invalid_document_source_is_ignored(source):
     )
 
 
-def test_set_invocation_response_attributes_records_cache_tokens():
+def test_set_invocation_response_attributes_records_usage_tokens():
     invocation = MagicMock()
     message = SimpleNamespace(
         id="msg_123",
@@ -469,6 +469,7 @@ def test_set_invocation_response_attributes_records_cache_tokens():
         usage=SimpleNamespace(
             input_tokens=10,
             output_tokens=20,
+            output_tokens_details=SimpleNamespace(thinking_tokens=12),
             cache_creation_input_tokens=15,
             cache_read_input_tokens=5,
         ),
@@ -478,10 +479,32 @@ def test_set_invocation_response_attributes_records_cache_tokens():
     )
     assert invocation.input_tokens == 30
     assert invocation.output_tokens == 20
+    assert invocation.thinking_tokens == 12
     assert invocation.cache_write_input_tokens == 15
     assert invocation.cache_read_input_tokens == 5
 
 
+def test_set_invocation_response_attributes_handles_missing_token_details():
+    invocation = MagicMock()
+    message = SimpleNamespace(
+        id="msg_123",
+        model="claude-3-7-sonnet-20250219",
+        stop_reason="end_turn",
+        usage=SimpleNamespace(
+            input_tokens=10,
+            output_tokens=20,
+            cache_creation_input_tokens=0,
+            cache_read_input_tokens=0,
+        ),
+    )
+
+    set_invocation_response_attributes(
+        invocation, message, capture_content=False
+    )
+
+    assert invocation.thinking_tokens is None
+
+
 def test_convert_server_tool_use_block():
     part = _convert_content_block_to_part(
         ServerToolUseBlock(

instrumentation/opentelemetry-instrumentation-genai-anthropic/tests/test_sync_messages.py

@@ -63,6 +63,10 @@
 _create_params = set(inspect.signature(_Messages.create).parameters)
 _has_tools_param = "tools" in _create_params
 _has_thinking_param = "thinking" in _create_params
+_usage_fields = getattr(Usage, "model_fields", None)
+if _usage_fields is None:
+    _usage_fields = getattr(Usage, "__fields__", {})
+_has_output_tokens_details = "output_tokens_details" in _usage_fields
 
 
 @pytest.mark.parametrize(
@@ -1423,7 +1427,7 @@ def test_sync_messages_create_captures_thinking_content(
     model = "claude-sonnet-4-20250514"
     messages = [{"role": "user", "content": "What is 17*19? Think first."}]
 
-    anthropic_client.messages.create(
+    response = anthropic_client.messages.create(
         model=model,
         max_tokens=16000,
         messages=messages,
@@ -1442,6 +1446,16 @@ def test_sync_messages_create_captures_thinking_content(
         for message in output_messages
         for part in message.get("parts", [])
     )
+    if _has_output_tokens_details:
+        assert response.usage.output_tokens_details is not None
+        thinking_tokens = response.usage.output_tokens_details.thinking_tokens
+        assert thinking_tokens > 0
+        assert (
+            span.attributes[
+                GenAIAttributes.GEN_AI_USAGE_REASONING_OUTPUT_TOKENS
+            ]
+            == thinking_tokens
+        )
 
 
 @pytest.mark.vcr()