diff --git a/src/openai/types/beta/beta_response_function_call_arguments_done_event.py b/src/openai/types/beta/beta_response_function_call_arguments_done_event.py
index b9ded692bb..bdda249db7 100644
--- a/src/openai/types/beta/beta_response_function_call_arguments_done_event.py
+++ b/src/openai/types/beta/beta_response_function_call_arguments_done_event.py
@@ -24,9 +24,6 @@ class BetaResponseFunctionCallArgumentsDoneEvent(BaseModel):
     item_id: str
     """The ID of the item."""
 
-    name: str
-    """The name of the function that was called."""
-
     output_index: int
     """The index of the output item."""
 
@@ -35,5 +32,13 @@ class BetaResponseFunctionCallArgumentsDoneEvent(BaseModel):
 
     type: Literal["response.function_call_arguments.done"]
 
+    name: Optional[str] = None
+    """The name of the function that was called.
+
+    The live Responses API may omit this field on
+    `response.function_call_arguments.done` events; correlate via `item_id` when
+    absent.
+    """
+
     agent: Optional[Agent] = None
     """The agent that owns this multi-agent streaming event."""
diff --git a/src/openai/types/responses/response_function_call_arguments_done_event.py b/src/openai/types/responses/response_function_call_arguments_done_event.py
index 543cd073a2..5810dac169 100644
--- a/src/openai/types/responses/response_function_call_arguments_done_event.py
+++ b/src/openai/types/responses/response_function_call_arguments_done_event.py
@@ -1,5 +1,6 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
+from typing import Optional
 from typing_extensions import Literal
 
 from ..._models import BaseModel
@@ -16,9 +17,6 @@ class ResponseFunctionCallArgumentsDoneEvent(BaseModel):
     item_id: str
     """The ID of the item."""
 
-    name: str
-    """The name of the function that was called."""
-
     output_index: int
     """The index of the output item."""
 
@@ -26,3 +24,11 @@ class ResponseFunctionCallArgumentsDoneEvent(BaseModel):
     """The sequence number of this event."""
 
     type: Literal["response.function_call_arguments.done"]
+
+    name: Optional[str] = None
+    """The name of the function that was called.
+
+    The live Responses API may omit this field on
+    `response.function_call_arguments.done` events; correlate via `item_id` when
+    absent.
+    """
diff --git a/tests/test_response_function_call_arguments_done_event.py b/tests/test_response_function_call_arguments_done_event.py
new file mode 100644
index 0000000000..8595a92eae
--- /dev/null
+++ b/tests/test_response_function_call_arguments_done_event.py
@@ -0,0 +1,49 @@
+from __future__ import annotations
+
+import pydantic
+import pytest
+
+from openai.types.beta.beta_response_function_call_arguments_done_event import (
+    BetaResponseFunctionCallArgumentsDoneEvent,
+)
+from openai.types.responses.response_function_call_arguments_done_event import (
+    ResponseFunctionCallArgumentsDoneEvent,
+)
+from openai.types.responses.response_stream_event import ResponseStreamEvent
+
+
+PAYLOAD_WITHOUT_NAME = {
+    "type": "response.function_call_arguments.done",
+    "arguments": "{\"city\": \"Paris\"}",
+    "item_id": "fc_test_item",
+    "output_index": 2,
+    "sequence_number": 10,
+}
+
+
+def test_function_call_arguments_done_accepts_missing_name() -> None:
+    """Live Responses API may omit `name` on done events (issue #3472)."""
+    event = ResponseFunctionCallArgumentsDoneEvent.model_validate(PAYLOAD_WITHOUT_NAME)
+    assert event.type == "response.function_call_arguments.done"
+    assert event.item_id == "fc_test_item"
+    assert event.name is None
+    assert event.arguments == '{"city": "Paris"}'
+
+
+def test_function_call_arguments_done_keeps_name_when_present() -> None:
+    event = ResponseFunctionCallArgumentsDoneEvent.model_validate(
+        {**PAYLOAD_WITHOUT_NAME, "name": "get_weather"}
+    )
+    assert event.name == "get_weather"
+
+
+def test_response_stream_event_union_accepts_done_without_name() -> None:
+    # Strict union validation previously failed with missing: name.
+    event = pydantic.TypeAdapter(ResponseStreamEvent).validate_python(PAYLOAD_WITHOUT_NAME)
+    assert isinstance(event, ResponseFunctionCallArgumentsDoneEvent)
+    assert event.name is None
+
+
+def test_beta_function_call_arguments_done_accepts_missing_name() -> None:
+    event = BetaResponseFunctionCallArgumentsDoneEvent.model_validate(PAYLOAD_WITHOUT_NAME)
+    assert event.name is None