Python: Create/Get Agent API for OpenAI Assistants

[dmytrostruk]

Motivation and Context

This PR contains an implementation of create/get API with Provider type for OpenAI Assistants chat client, based on Option 2 from this ADR.

Example:

from agent_framework.openai import OpenAIAssistantProvider
from openai import OpenAI

client = OpenAI()
provider = OpenAIAssistantProvider(client)

agent = await provider.create_agent(name="MyAssistant", model="gpt-4", instructions="...")
agent = await provider.get_agent(assistant_id="asst_123")
agent = provider.as_agent(assistant)

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

This PR introduces a new OpenAIAssistantProvider class that provides a clean, provider-based API for creating and managing OpenAI Assistant agents. This implements Option 2 from ADR #2618, offering three key methods: create_agent() to create new assistants, get_agent() to retrieve existing assistants by ID, and as_agent() to wrap SDK Assistant objects without additional HTTP calls.

Changes:

• Added OpenAIAssistantProvider class with create/get/as_agent methods
• Refactored tool conversion utilities to shared module for reuse
• Updated all OpenAI Assistants samples to use the new provider API
• Added comprehensive unit tests for the provider

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
python/packages/core/agent_framework/openai/_assistant_provider.py	New provider class with create_agent, get_agent, and as_agent methods
python/packages/core/agent_framework/openai/_shared.py	Added tool conversion utilities (to_assistant_tools, from_assistant_tools)
python/packages/core/agent_framework/openai/_assistants_client.py	Refactored to use shared tool conversion utilities
python/packages/core/agent_framework/openai/__init__.py	Exports the new OpenAIAssistantProvider
python/packages/core/tests/openai/test_assistant_provider.py	Comprehensive unit tests covering all provider functionality
python/samples/getting_started/agents/openai/openai_assistants_basic.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_provider_methods.py	New sample demonstrating all provider methods
python/samples/getting_started/agents/openai/openai_assistants_with_response_format.py	New sample showing structured output with response_format
python/samples/getting_started/agents/openai/openai_assistants_with_thread.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_with_function_tools.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_with_file_search.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_with_code_interpreter.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_with_explicit_settings.py	Updated to use provider API
python/samples/getting_started/agents/openai/openai_assistants_with_existing_assistant.py	Updated to demonstrate get_agent and as_agent methods
python/samples/getting_started/agents/openai/README.md	Updated documentation for all samples

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework/openai
_assistant_provider.py	109	11	89%	153–154, 166, 291, 357, 472–477
_shared.py	132	15	88%	63, 69–72, 150, 152, 159, 161, 174, 250, 274, 338–339, 341
TOTAL	17361	2666	84%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3141	213 💤	0 ❌	0 🔥	1m 5s ⏱️