Python: Record actual served model from Azure OpenAI (#5910)

* Record actual served model as response model for Azure OpenAI

* Formatting

* Fix tests

* Fix pipeline error

* Comments

* Address review: surface served model via ChatResponse.model

Apply blocking review feedback from PR #5910:

- Use ChatResponse.model / ChatResponseUpdate.model as the source of truth
  for the Azure x-ms-served-model header value, instead of stashing it in
  additional_properties and overriding it again in observability.
  Observability already reads response.model; the chat client now overwrites
  it post-parse when the served-model header is present. Empirically the
  Azure Responses API returns the deployment alias in body.model and the
  actual snapshot (e.g. gpt-5-nano-2025-08-07) in this header.

- Move the AZURE_OPENAI_SERVED_MODEL_HEADER constant out of observability.py
  and into RawOpenAIChatClient (as the SERVED_MODEL_HEADER ClassVar). The
  header is Azure-OpenAI-Responses-API-specific so observability does not
  need to know about it.

- Revert the streaming text_format path to client.responses.stream(...) and
  drop the _pydantic_model_to_text_format_param helper. That helper imported
  from openai.lib._parsing._responses (a private SDK path) and the swap to
  responses.create(stream=True) dropped client-side output_parsed for
  structured-output streaming. The streaming-with-text_format path is the
  only one that does not surface the served-model header - documented inline.

- Wrap the raw streaming responses in async with so the underlying socket
  closes deterministically (continuation_token retrieve + create paths).

- Fix the empty-string / whitespace-only header at the source by stripping
  in _extract_served_model and returning None when nothing remains.

- Revert unrelated formatting-only churn in _skills.py and test_mcp.py.

- Update unit tests to assert against chat_response.model / update.model
  and add an aggregated streaming assertion plus a pin that the
  streaming-with-text_format path does not get the header.

Verified end-to-end against Azure OpenAI Responses API: deployment alias
gpt-5-nano now reports gpt-5-nano-2025-08-07 as ChatResponse.model in both
the non-streaming and streaming paths.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: preserve streaming structured output finalization

Agent-Logs-Url: https://github.com/microsoft/agent-framework/sessions/f62076ef-558d-49e8-8fe2-f38d527c9639

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* refactor: name streaming response finalizer

Agent-Logs-Url: https://github.com/microsoft/agent-framework/sessions/f62076ef-558d-49e8-8fe2-f38d527c9639

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* fix: capture streaming response format after prepare

Agent-Logs-Url: https://github.com/microsoft/agent-framework/sessions/f62076ef-558d-49e8-8fe2-f38d527c9639

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* refactor: clarify streaming response format capture

Agent-Logs-Url: https://github.com/microsoft/agent-framework/sessions/f62076ef-558d-49e8-8fe2-f38d527c9639

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* test: use public API for streaming structured output

Agent-Logs-Url: https://github.com/microsoft/agent-framework/sessions/f62076ef-558d-49e8-8fe2-f38d527c9639

Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

* Inline the served-model header override at its two call sites

The `_apply_served_model_header` helper was a 1-line wrapper around
`_extract_served_model`. Inlining the `if served_model is not None: ...`
matches the pattern already used in the streaming paths and folds the
explanatory docstring onto `_extract_served_model` (which is now the
single place that knows about the header).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Eduard van Valkenburg <eavanvalkenburg@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: eavanvalkenburg <13749212+eavanvalkenburg@users.noreply.github.com>

python/packages/core/agent_framework/_skills.py

@@ -651,9 +651,7 @@ def _validate_compatibility(compatibility: str | None) -> None:
         ValueError: If the value exceeds the maximum allowed length.
     """
     if compatibility is not None and len(compatibility) > MAX_COMPATIBILITY_LENGTH:
-        raise ValueError(
-            f"Skill compatibility must be {MAX_COMPATIBILITY_LENGTH} characters or fewer."
-        )
+        raise ValueError(f"Skill compatibility must be {MAX_COMPATIBILITY_LENGTH} characters or fewer.")
 
 
 def _build_skill_content(
@@ -733,6 +731,7 @@ class InlineSkill(Skill):
                 instructions="Use this skill for DB tasks.",
             )
 
+
             @skill.resource
             def get_schema() -> str:
                 return "CREATE TABLE ..."
@@ -2613,11 +2612,7 @@ class FileSkillsSource(SkillsSource):
 
             # Reject absolute paths (check both POSIX and Windows-style roots
             # so validation is consistent regardless of the host OS)
-            if (
-                os.path.isabs(directory)
-                or normalized.startswith("/")
-                or re.match(r"^[A-Za-z]:[/\\]", directory)
-            ):
+            if os.path.isabs(directory) or normalized.startswith("/") or re.match(r"^[A-Za-z]:[/\\]", directory):
                 logger.warning(
                     "Skipping directory '%s': absolute paths are not allowed.",
                     directory,

python/packages/core/tests/core/test_agents.py

@@ -2567,10 +2567,15 @@ async def test_shared_local_storage_cross_provider_responses_history_does_not_le
     responses_second.incomplete = None
     responses_second.output = [responses_text_item]
 
+    def _as_raw(resp: MagicMock) -> MagicMock:
+        resp.parse = MagicMock(return_value=resp)
+        resp.headers = {}
+        return resp
+
     with patch.object(
-        responses_client.client.responses,
+        responses_client.client.responses.with_raw_response,
         "create",
-        side_effect=[responses_first, responses_second],
+        side_effect=[_as_raw(responses_first), _as_raw(responses_second)],
     ) as mock_responses_create:
         responses_result = await responses_agent.run("Find me a hotel in Paris", session=session)
 

python/packages/core/tests/core/test_mcp.py

@@ -4227,9 +4227,7 @@ async def test_mcp_tool_call_tool_forwards_tool_list_meta():
             self.session.call_tool = AsyncMock(
                 return_value=types.CallToolResult(content=[types.TextContent(type="text", text="result")])
             )
-            self.session.list_prompts = AsyncMock(
-                return_value=types.ListPromptsResult(prompts=[])
-            )
+            self.session.list_prompts = AsyncMock(return_value=types.ListPromptsResult(prompts=[]))
 
         def get_mcp_client(self) -> _AsyncGeneratorContextManager[Any, None]:
             return None