Files
agent-framework/python/packages/core
T
Giles Odigwe 7d23582e2b Python: fix: prevent MCP message_handler deadlock on notification reload (#4866)
* fix(python): prevent MCP message_handler deadlock on notification reload

When an MCP server sends a notifications/tools/list_changed or
notifications/prompts/list_changed notification, the message_handler
previously awaited load_tools()/load_prompts() directly. Since the
handler runs on the MCP SDK's single-threaded receive loop, this
caused a deadlock: load_tools() sends a list_tools request and waits
for its response, but the receive loop cannot deliver that response
while blocked in the handler.

This manifested as a timeout in call_tool(), which then surfaced as
"Error: Function failed." to the model instead of the real tool
output. The MATLAB MCP server reliably triggers this because it sends
a tools/list_changed notification during tool execution.

Fix: schedule reloads as background asyncio.Tasks via a new
_schedule_reload() helper, freeing the receive loop immediately.

Fixes #4828

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

* Address PR review feedback: fix exc_info, coalesce reloads, shutdown cleanup, tests

- Fix exc_info=exc -> exc_info=True in _schedule_reload and message_handler
- Tighten _schedule_reload param type from Any to Coroutine[Any, Any, None]
- Coalesce reloads: cancel-and-replace per reload kind to prevent unbounded growth
- Cancel pending reload tasks in _close_on_owner before tearing down session
- Re-raise CancelledError in _safe_reload to respect task cancellation
- Replace flaky asyncio.sleep(0) with asyncio.wait_for/gather in tests
- Add caplog assertions to verify reload failure is actually logged
- Assert _pending_reload_tasks cleanup on error path

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

* fix: address review comments on MCP reload handling

- Fix exc_info=True -> exc_info=message in message_handler error logging,
  since the handler is not called from an except block
- Await cancelled reload tasks in _close_on_owner before tearing down
  the session to avoid 'Task was destroyed but pending' warnings
- Add cancel-and-replace test verifying duplicate notifications cancel
  the first reload task and only keep one in flight

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

* fix: remove Task.cancelling() call for Python 3.10 compat

Task.cancelling() was added in Python 3.11. Replace with awaiting
the task and checking cancelled() instead.

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

* Add debug log when cancelling superseded reload task

Log at DEBUG level when a new notification cancels an in-flight reload
task, improving observability of the cancel-and-replace behavior.

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

---------

Co-authored-by: Copilot <copilot@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
7d23582e2b · 2026-05-13 20:09:59 +00:00
History
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2025-09-30 07:18:36 +00:00

Get Started with Microsoft Agent Framework

Highlights

  • Flexible Agent Framework: build, orchestrate, and deploy AI agents and multi-agent systems
  • Multi-Agent Orchestration: Group chat, sequential, concurrent, and handoff patterns
  • Plugin Ecosystem: Extend with native functions, OpenAPI, Model Context Protocol (MCP), and more
  • LLM Support: OpenAI, Foundry, Anthropic, and more
  • Runtime Support: In-process and distributed agent execution
  • Multimodal: Text, vision, and function calling
  • Cross-Platform: .NET and Python implementations

Quick Install

pip install agent-framework-core
# Optional: Add Azure AI Foundry integration
pip install agent-framework-foundry
# Optional: Add OpenAI integration
pip install agent-framework-openai

Supported Platforms:

  • Python: 3.10+
  • OS: Windows, macOS, Linux

1. Setup API Keys

Depending on the client you want to use, there are various environment variables you can set to configure the chat clients. This can be done in the environment itself, or with a .env file in your project root, some examples of environment variables include:

FOUNDRY_PROJECT_ENDPOINT=...
FOUNDRY_MODEL=...
...
OPENAI_API_KEY=sk-...
OPENAI_CHAT_COMPLETION_MODEL=...
OPENAI_CHAT_MODEL=...
...
AZURE_OPENAI_API_KEY=...
AZURE_OPENAI_ENDPOINT=...
AZURE_OPENAI_MODEL=...

You can also override environment variables by explicitly passing configuration parameters to the chat client constructor:

from agent_framework.openai import OpenAIChatClient

client = OpenAIChatClient(
    api_key="",
    model="",
)

See the following getting started samples for more information.

2. Create a Simple Agent

Create agents and invoke them directly:

import asyncio
from agent_framework import Agent
from agent_framework.openai import OpenAIChatClient

agent = Agent(
    client=OpenAIChatClient(),
    instructions="""
    1) A robot may not injure a human being...
    2) A robot must obey orders given it by human beings...
    3) A robot must protect its own existence...

    Give me the TLDR in exactly 5 words.
    """
)

result = asyncio.run(agent.run("Summarize the Three Laws of Robotics"))
print(result)
# Output: Protect humans, obey, self-preserve, prioritized.

3. Directly Use Chat Clients (No Agent Required)

You can use the chat client classes directly for advanced workflows:

import asyncio
from agent_framework.openai import OpenAIChatClient
from agent_framework import Message, Role

async def main():
    client = OpenAIChatClient()

    response = await client.get_response([
        Message("system", ["You are a helpful assistant."]),
        Message("user", ["Write a haiku about Agent Framework."])
    ])
    print(response.messages[0].text)

    """
    Output:

    Agents work in sync,
    Framework threads through each task—
    Code sparks collaboration.
    """

asyncio.run(main())

4. Build an Agent with Tools and Functions

Enhance your agent with custom tools and function calling:

import asyncio
from typing import Annotated
from random import randint
from agent_framework import Agent
from agent_framework.openai import OpenAIChatClient


def get_weather(
    location: Annotated[str, "The location to get the weather for."],
) -> str:
    """Get the weather for a given location."""
    conditions = ["sunny", "cloudy", "rainy", "stormy"]
    return f"The weather in {location} is {conditions[randint(0, 3)]} with a high of {randint(10, 30)}°C."


def get_menu_specials() -> str:
    """Get today's menu specials."""
    return """
    Special Soup: Clam Chowder
    Special Salad: Cobb Salad
    Special Drink: Chai Tea
    """


async def main():
    agent = Agent(
        client=OpenAIChatClient(),
        instructions="You are a helpful assistant that can provide weather and restaurant information.",
        tools=[get_weather, get_menu_specials]
    )

    response = await agent.run("What's the weather in Amsterdam and what are today's specials?")
    print(response)

    # Output:
    # The weather in Amsterdam is sunny with a high of 22°C. Today's specials include
    # Clam Chowder soup, Cobb Salad, and Chai Tea as the special drink.

asyncio.run(main())

You can explore additional agent samples here.

5. Multi-Agent Orchestration

Coordinate multiple agents to collaborate on complex tasks using orchestration patterns:

import asyncio
from agent_framework import Agent
from agent_framework.openai import OpenAIChatClient


async def main():
    # Create specialized agents
    writer = Agent(
        client=OpenAIChatClient(),
        name="Writer",
        instructions="You are a creative content writer. Generate and refine slogans based on feedback."
    )

    reviewer = Agent(
        client=OpenAIChatClient(),
        name="Reviewer",
        instructions="You are a critical reviewer. Provide detailed feedback on proposed slogans."
    )

    # Sequential workflow: Writer creates, Reviewer provides feedback
    task = "Create a slogan for a new electric SUV that is affordable and fun to drive."

    # Step 1: Writer creates initial slogan
    initial_result = await writer.run(task)
    print(f"Writer: {initial_result}")

    # Step 2: Reviewer provides feedback
    feedback_request = f"Please review this slogan: {initial_result}"
    feedback = await reviewer.run(feedback_request)
    print(f"Reviewer: {feedback}")

    # Step 3: Writer refines based on feedback
    refinement_request = f"Please refine this slogan based on the feedback: {initial_result}\nFeedback: {feedback}"
    final_result = await writer.run(refinement_request)
    print(f"Final Slogan: {final_result}")

    # Example Output:
    # Writer: "Charge Forward: Affordable Adventure Awaits!"
    # Reviewer: "Good energy, but 'Charge Forward' is overused in EV marketing..."
    # Final Slogan: "Power Up Your Adventure: Premium Feel, Smart Price!"

if __name__ == "__main__":
    asyncio.run(main())

Note: Sequential, Concurrent, Group Chat, Handoff, and Magentic orchestrations are available. See examples in orchestration samples.

More Examples & Samples

Agent Framework Documentation