ref(anthropic): Simplify finish_reasons to single finish_reason internally

Anthropic only returns a single stop_reason, so track it as a string
internally instead of a list. The list wrapping is deferred to
_set_output_data where it's set on the span. Also removes an
unnecessary getattr guard for event.delta.stop_reason.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ericapisani

sentry_sdk/integrations/anthropic.py

@@ -159,8 +159,8 @@ def _collect_ai_data(
     usage: "_RecordedUsage",
     content_blocks: "list[str]",
     response_id: "str | None" = None,
-    finish_reasons: "list[str] | None" = None,
-) -> "tuple[str | None, _RecordedUsage, list[str], str | None, list[str] | None]":
+    finish_reason: "str | None" = None,
+) -> "tuple[str | None, _RecordedUsage, list[str], str | None, str | None]":
     """
     Collect model information, token usage, and collect content blocks from the AI streaming response.
     """
@@ -198,7 +198,7 @@ def _collect_ai_data(
                     usage,
                     content_blocks,
                     response_id,
-                    finish_reasons,
+                    finish_reason,
                 )
 
             # Counterintuitive, but message_delta contains cumulative token counts :)
@@ -223,18 +223,17 @@ def _collect_ai_data(
                     usage.cache_read_input_tokens = cache_read_input_tokens
                 # TODO: Record event.usage.server_tool_use
 
-                stop_reason = getattr(event.delta, "stop_reason", None)
-                if stop_reason is not None:
-                    finish_reasons = [stop_reason]
+                if event.delta.stop_reason is not None:
+                    finish_reason = event.delta.stop_reason
 
-                return (model, usage, content_blocks, response_id, finish_reasons)
+                return (model, usage, content_blocks, response_id, finish_reason)
 
     return (
         model,
         usage,
         content_blocks,
         response_id,
-        finish_reasons,
+        finish_reason,
     )
 
 
@@ -413,7 +412,7 @@ def _wrap_synchronous_message_iterator(
     usage = _RecordedUsage()
     content_blocks: "list[str]" = []
     response_id = None
-    finish_reasons = None
+    finish_reason = None
 
     try:
         for event in iterator:
@@ -433,14 +432,14 @@ def _wrap_synchronous_message_iterator(
                 yield event
                 continue
 
-            (model, usage, content_blocks, response_id, finish_reasons) = (
+            (model, usage, content_blocks, response_id, finish_reason) = (
                 _collect_ai_data(
                     event,
                     model,
                     usage,
                     content_blocks,
                     response_id,
-                    finish_reasons,
+                    finish_reason,
                 )
             )
             yield event
@@ -465,7 +464,7 @@ def _wrap_synchronous_message_iterator(
                 content_blocks=[{"text": "".join(content_blocks), "type": "text"}],
                 finish_span=True,
                 response_id=response_id,
-                finish_reasons=finish_reasons,
+                finish_reason=finish_reason,
             )
 
 
@@ -482,7 +481,7 @@ async def _wrap_asynchronous_message_iterator(
     usage = _RecordedUsage()
     content_blocks: "list[str]" = []
     response_id = None
-    finish_reasons = None
+    finish_reason = None
 
     try:
         async for event in iterator:
@@ -507,14 +506,14 @@ async def _wrap_asynchronous_message_iterator(
                 usage,
                 content_blocks,
                 response_id,
-                finish_reasons,
+                finish_reason,
             ) = _collect_ai_data(
                 event,
                 model,
                 usage,
                 content_blocks,
                 response_id,
-                finish_reasons,
+                finish_reason,
             )
             yield event
     finally:
@@ -538,7 +537,7 @@ async def _wrap_asynchronous_message_iterator(
                 content_blocks=[{"text": "".join(content_blocks), "type": "text"}],
                 finish_span=True,
                 response_id=response_id,
-                finish_reasons=finish_reasons,
+                finish_reason=finish_reason,
             )
 
 
@@ -553,15 +552,15 @@ def _set_output_data(
     content_blocks: "list[Any]",
     finish_span: bool = False,
     response_id: "str | None" = None,
-    finish_reasons: "list[str] | None" = None,
+    finish_reason: "str | None" = None,
 ) -> None:
     """
     Set output data for the span based on the AI response."""
     span.set_data(SPANDATA.GEN_AI_RESPONSE_MODEL, model)
     if response_id is not None:
         span.set_data(SPANDATA.GEN_AI_RESPONSE_ID, response_id)
-    if finish_reasons is not None:
-        span.set_data(SPANDATA.GEN_AI_RESPONSE_FINISH_REASONS, finish_reasons)
+    if finish_reason is not None:
+        span.set_data(SPANDATA.GEN_AI_RESPONSE_FINISH_REASONS, [finish_reason])
     if should_send_default_pii() and integration.include_prompts:
         output_messages: "dict[str, list[Any]]" = {
             "response": [],
@@ -655,10 +654,6 @@ def _sentry_patched_create_common(f: "Any", *args: "Any", **kwargs: "Any") -> "A
                 elif hasattr(content_block, "text"):
                     content_blocks.append({"type": "text", "text": content_block.text})
 
-            finish_reasons = None
-            if getattr(result, "stop_reason", None) is not None:
-                finish_reasons = [getattr(result, "stop_reason")]
-
             _set_output_data(
                 span=span,
                 integration=integration,
@@ -670,7 +665,7 @@ def _sentry_patched_create_common(f: "Any", *args: "Any", **kwargs: "Any") -> "A
                 content_blocks=content_blocks,
                 finish_span=True,
                 response_id=getattr(result, "id", None),
-                finish_reasons=finish_reasons,
+                finish_reason=getattr(result, "stop_reason", None),
             )
         else:
             span.set_data("unknown_response", True)

tests/integrations/anthropic/test_anthropic.py

@@ -1477,15 +1477,15 @@ def test_collect_ai_data_with_input_json_delta():
 
     content_blocks = []
 
-    model, new_usage, new_content_blocks, response_id, finish_reasons = (
-        _collect_ai_data(event, model, usage, content_blocks)
+    model, new_usage, new_content_blocks, response_id, finish_reason = _collect_ai_data(
+        event, model, usage, content_blocks
     )
     assert model is None
     assert new_usage.input_tokens == usage.input_tokens
     assert new_usage.output_tokens == usage.output_tokens
     assert new_content_blocks == ["test"]
     assert response_id is None
-    assert finish_reasons is None
+    assert finish_reason is None
 
 
 @pytest.mark.skipif(