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
2,072 Commits
2025-10-30 20:29:01 +00:00
2025-04-28 12:54:43 -07:00
2025-04-28 12:54:42 -07:00

Microsoft Agent Framework

Welcome to Microsoft Agent Framework!

Microsoft Foundry Discord MS Learn Documentation PyPI NuGet GitHub stars

Microsoft Agent Framework (MAF) is an open, multi-language framework for building production-grade AI agents and multi-agent workflows in .NET and Python.

Microsoft Agent Framework is built for teams taking agents from prototype to production. It provides a consistent foundation for building, orchestrating, and operating agent systems across Python and .NET, while keeping architecture choices open as requirements evolve, and supports a broad ecosystem including Microsoft Foundry, Azure OpenAI, OpenAI, and the GitHub Copilot SDK, with samples and hosting patterns for both local development and cloud deployment.

Watch the full Agent Framework introduction (30 min)

Watch the full Agent Framework introduction (30 min)

Is this the right framework for you?

MAF is a strong fit if you:

  • are building agents and workflows you expect to run in production,
  • need orchestration beyond a single prompt or stateless chat loop,
  • want graph-based patterns such as sequential, concurrent, handoff, and group collaboration,
  • care about durability, restartability, observability, governance, or human-in-the-loop control,
  • need provider flexibility so your architecture can evolve without major rewrites.

Key Features

Explore new MAF capabilities and real implementation patterns on the official blog.

  • Python and C#/.NET Support: Full framework support for both Python and C#/.NET implementations with consistent APIs
  • Multiple Agent Provider Support: Support for various LLM providers with more being added continuously
  • Middleware: Flexible middleware system for request/response processing, exception handling, and custom pipelines
  • Orchestration Patterns & Workflows: Build multi-agent systems with graph-based workflows supporting sequential, concurrent, handoff, and group collaboration patterns; includes checkpointing, streaming, human-in-the-loop, and time-travel
  • Foundry Hosted Agents (new): Deploy and host your agents to Foundry-hosted infrastructure with just 2 additional lines of code
  • Observability: Built-in OpenTelemetry integration for distributed tracing, monitoring, and debugging
  • Declarative Agents: Define agents using YAML for faster setup and versioning
  • Agent Skills: Build domain-specific knowledge bases from multiple sources—files, inline code, class libraries—for agents to discover and use
  • AF Labs: Experimental packages for cutting-edge features including benchmarking, reinforcement learning, and research initiatives
  • DevUI: Interactive developer UI for agent development, testing, and debugging workflows

Table of Contents

Getting Started

Installation

Python

pip install agent-framework
# This will install all sub-packages, see `python/packages` for individual packages.
# It may take a minute on first install on Windows.

.NET

dotnet add package Microsoft.Agents.AI
# For Foundry integration (used in the .NET quickstart below):
dotnet add package Microsoft.Agents.AI.Foundry
dotnet add package Azure.AI.Projects
dotnet add package Azure.Identity

Learning Resources

Quickstart

Basic Agent - Python

Create a simple Azure Responses Agent that writes a haiku about the Microsoft Agent Framework

# pip install agent-framework
# Use `az login` to authenticate with Azure CLI
import os
import asyncio
from agent_framework import Agent
from agent_framework.foundry import FoundryChatClient
from azure.identity import AzureCliCredential


async def main():
    # Initialize a chat agent with Microsoft Foundry
    # the endpoint, deployment name, and api version can be set via environment variables
    # or they can be passed in directly to the FoundryChatClient constructor
    agent = Agent(
      client=FoundryChatClient(
          credential=AzureCliCredential(),
          # project_endpoint=os.environ["FOUNDRY_PROJECT_ENDPOINT"],
          # model=os.environ["FOUNDRY_MODEL_DEPLOYMENT_NAME"],
      ),
      name="HaikuAgent",
      instructions="You are an upbeat assistant that writes beautifully.",
    )

    print(await agent.run("Write a haiku about Microsoft Agent Framework."))

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

Basic Agent - .NET

Create a simple Agent, using Microsoft Foundry that writes a haiku about the Microsoft Agent Framework

// This sample shows how to create and run a basic agent with AIProjectClient.AsAIAgent(...).

using Azure.AI.Projects;
using Azure.Identity;
using Microsoft.Agents.AI;

string endpoint = Environment.GetEnvironmentVariable("AZURE_AI_PROJECT_ENDPOINT") ?? throw new InvalidOperationException("AZURE_AI_PROJECT_ENDPOINT is not set.");
string deploymentName = Environment.GetEnvironmentVariable("AZURE_AI_MODEL_DEPLOYMENT_NAME") ?? "gpt-5.4-mini";

AIAgent agent =
    new AIProjectClient(new Uri(endpoint), new DefaultAzureCredential())
    .AsAIAgent(model: deploymentName, instructions: "You are an upbeat assistant that writes beautifully.", name: "HaikuAgent");

// Once you have the agent, you can invoke it like any other AIAgent.
Console.WriteLine(await agent.RunAsync("Write a haiku about Microsoft Agent Framework."));

More Examples & Samples

Python

  • Getting Started: progressive tutorial from hello-world to hosting
  • Agent Concepts: deep-dive samples by topic (tools, middleware, providers, etc.)
  • Workflows: workflow creation and integration with agents
  • Hosting: A2A, Azure Functions, Durable Task hosting
  • End-to-End: full applications, evaluation, and demos

.NET

Community & Feedback

  • Found a bug? File a GitHub issue to help us improve.
  • Enjoying MAF? GitHub stars to show your support and help others discover the project.
  • Have questions? Join our Discord or visit weekly office hours.

Troubleshooting

Authentication

Problem Cause Fix
Authentication errors when using Azure credentials Not signed in to Azure CLI Run az login before starting your app
API key errors Wrong or missing API key Verify the key and ensure it's for the correct resource/provider

Tip: DefaultAzureCredential is convenient for development but in production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid latency issues, unintended credential probing, and potential security risks from fallback mechanisms.

Environment Variables

For environment variable configuration specific to each sample, refer to the README in the sample directory (Python samples | .NET samples).

Contributor Resources

Important Notes

Important

If you use Microsoft Agent Framework to build applications that operate with any third-party servers, agents, code, or non-Azure Direct models (“Third-Party Systems”), you do so at your own risk. Third-Party Systems are Non-Microsoft Products under the Microsoft Product Terms and are governed by their own third-party license terms. You are responsible for any usage and associated costs.

We recommend reviewing all data being shared with and received from Third-Party Systems and being cognizant of third-party practices for handling, sharing, retention and location of data. It is your responsibility to manage whether your data will flow outside of your organizations Azure compliance and geographic boundaries and any related implications, and that appropriate permissions, boundaries and approvals are provisioned.

You are responsible for carefully reviewing and testing applications you build using Microsoft Agent Framework in the context of your specific use cases, and making all appropriate decisions and customizations. This includes implementing your own responsible AI mitigations such as metaprompt, content filters, or other safety systems, and ensuring your applications meet appropriate quality, reliability, security, and trustworthiness standards. See also: Transparency FAQ

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