`OpenAIChatClient._inner_get_response()` reads `.headers` on the raw streaming response returned by `client.responses.with_raw_response.create(stream=True)` (and its three sibling call sites - retrieve-streaming, non-streaming create and background retrieve) to surface the `x-ms-served-model` Azure header, introduced in #5910. When `azure-ai-projects>=2.1.0` experimental GenAI tracing is enabled (`AZURE_EXPERIMENTAL_ENABLE_GENAI_TRACING=true`), the instrumentor wraps the raw streaming response in an inline `AsyncStreamWrapper` that exposes `.response` but not `.headers`. Reading `raw_create_response.headers` then raises `AttributeError: 'AsyncStreamWrapper' object has no attribute 'headers'`, which `FoundryChatClient` rethrows as a `ChatClientException` and breaks every streaming call (workflows and free chat). Fix: read the header dict via `getattr(raw_response, "headers", None)` at all four call sites. `_extract_served_model()` already short-circuits on `None`, so the served-model surfacing degrades gracefully (model stays the deployment alias) instead of crashing when the response is wrapped by an instrumentor that does not proxy `.headers`. Regression test added: `test_streaming_response_without_headers_attribute_does_not_crash` simulates a stream wrapper that raises `AttributeError` on `.headers` and asserts the stream still completes with the deployment alias as `update.model`. Fixes #6028 Co-authored-by: Emilien Mottet <emilien.mottet@michelin.com>
agent-framework-openai
OpenAI integration for Microsoft Agent Framework.
This package provides:
OpenAIChatClientfor the OpenAI Responses APIOpenAIChatCompletionClientfor the Chat Completions APIOpenAIEmbeddingClientfor embeddings
Installation
pip install agent-framework-openai
Which chat client should I use?
Use OpenAIChatClient for new work unless you specifically need the Chat Completions API.
OpenAIChatClientuses the Responses API and is the preferred general-purpose chat client.OpenAIChatCompletionClientuses the Chat Completions API and is mainly for compatibility with existing Chat Completions-based integrations.
The previous deprecated Responses alias has been removed. Use OpenAIChatClient directly.
Environment variables
OpenAI
These variables are used when the client is configured for OpenAI:
| Variable | Purpose |
|---|---|
OPENAI_API_KEY |
OpenAI API key |
OPENAI_ORG_ID |
OpenAI organization ID |
OPENAI_BASE_URL |
Custom OpenAI-compatible base URL |
OPENAI_MODEL |
Generic fallback model |
OPENAI_CHAT_MODEL |
Preferred model for OpenAIChatClient |
OPENAI_CHAT_COMPLETION_MODEL |
Preferred model for OpenAIChatCompletionClient |
OPENAI_EMBEDDING_MODEL |
Preferred model for OpenAIEmbeddingClient |
Model lookup order:
OpenAIChatClient:OPENAI_CHAT_MODEL->OPENAI_MODELOpenAIChatCompletionClient:OPENAI_CHAT_COMPLETION_MODEL->OPENAI_MODELOpenAIEmbeddingClient:OPENAI_EMBEDDING_MODEL->OPENAI_MODEL
These model variables are only consulted when you do not pass model= directly. In other words,
OpenAIChatClient(model="...") ignores OPENAI_CHAT_MODEL, and
OpenAIChatCompletionClient(model="...") ignores OPENAI_CHAT_COMPLETION_MODEL.
Azure OpenAI
These variables are used when the client is configured for Azure OpenAI:
| Variable | Purpose |
|---|---|
AZURE_OPENAI_ENDPOINT |
Azure OpenAI resource endpoint |
AZURE_OPENAI_BASE_URL |
Full Azure OpenAI base URL (.../openai/v1) |
AZURE_OPENAI_API_KEY |
Azure OpenAI API key |
AZURE_OPENAI_API_VERSION |
Azure OpenAI API version |
AZURE_OPENAI_MODEL |
Generic fallback deployment |
AZURE_OPENAI_CHAT_MODEL |
Preferred deployment for OpenAIChatClient |
AZURE_OPENAI_CHAT_COMPLETION_MODEL |
Preferred deployment for OpenAIChatCompletionClient |
AZURE_OPENAI_EMBEDDING_MODEL |
Preferred deployment for OpenAIEmbeddingClient |
Deployment lookup order:
OpenAIChatClient:AZURE_OPENAI_CHAT_MODEL->AZURE_OPENAI_MODELOpenAIChatCompletionClient:AZURE_OPENAI_CHAT_COMPLETION_MODEL->AZURE_OPENAI_MODELOpenAIEmbeddingClient:AZURE_OPENAI_EMBEDDING_MODEL->AZURE_OPENAI_MODEL
For Azure routing, the same rule applies: the client-specific deployment variable is checked first,
then the generic AZURE_OPENAI_MODEL fallback. Passing model= overrides both environment variables.
When both OpenAI and Azure environment variables are present, the generic clients prefer OpenAI
when OPENAI_API_KEY is configured. To use Azure explicitly, pass azure_endpoint or
credential.
OpenAI example
from agent_framework.openai import OpenAIChatClient
client = OpenAIChatClient(model="gpt-4.1")
Azure OpenAI example
from azure.identity.aio import AzureCliCredential
from agent_framework.openai import OpenAIChatClient
client = OpenAIChatClient(
model="my-responses-deployment",
azure_endpoint="https://my-resource.openai.azure.com",
credential=AzureCliCredential(),
)
ChatClient vs ChatCompletionClient
Use OpenAIChatClient when you want the Responses API as your default chat surface.
Use OpenAIChatCompletionClient when you specifically need the Chat Completions API:
from agent_framework.openai import OpenAIChatCompletionClient
client = OpenAIChatCompletionClient(model="gpt-4o-mini")