Files
microsoft--agent-framework/python
MohammadHaroonAbuomar 58da0cc253 Python: add MiddlewareFailure, a first-class fatal signal for function middleware (#7562)
* feat(core): first-class fatal signal (MiddlewareFailure) for function middleware

The function-invocation loop converts every exception raised by
function middleware into a tool-error result and keeps looping, so
middleware that needs fail-closed semantics (enforcement layers,
guardrails) had no loud escape: the agent-hooks feature simulated one
by mutating shared run state, raising MiddlewareTermination, and
re-raising the real failure two hops away at the run boundary.

Introduce MiddlewareFailure (a MiddlewareException sibling of
MiddlewareTermination) as the loop's explicit fail-closed escape:

- _auto_invoke_function re-raises it (both the direct and the
  pipeline path) instead of absorbing it into a tool-error result;
  ordinary exceptions keep the absorb-and-continue contract.
- A failing call fails the whole parallel batch: in-flight sibling
  tool tasks are cancelled and awaited before the failure propagates.
- Every existing MiddlewareTermination absorb site (agent/chat
  pipelines, _execute_single_function_call, harness loop, purview)
  passes it through untouched by construction, and agent/chat
  middleware exceptions already propagate, so one exception type
  gives uniform fail-loud semantics across all three categories.

Migrate the agent-hooks feature to the new signal: delete the
_RunState.halted back-channel and its three run-boundary re-raise
checks, drop the halted arm of the termination special case in the
function middleware (the approval-request pass-through moves to the
single approval check on the normal path), and fail partial installs
loudly. Tool-seam host_error blocks keep surfacing as
InterceptionBlocked at the run boundary via the exception cause chain
(one deny surface at every seam, pinned by tests).

Spec 004 gains the middleware-failure invariants and matrix rows.

Closes #7522

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>

* fix(core): harden tool-seam unwrap and pin review findings

Review round follow-ups for the MiddlewareFailure feature:

- Only agent-hooks' own tagged tool-seam halts (_ToolSeamBlockFailure)
  authorize re-raising the chained InterceptionBlocked at the run
  boundary; a third-party MiddlewareFailure with a crafted
  InterceptionBlocked cause now propagates as raised instead of
  laundering an attacker-shaped interception record into the feature's
  deny surface (regression test added, verified by mutation).
- Document that middleware must not catch MiddlewareFailure (docstring
  and spec 004): swallowing it converts a fail-closed abort back into
  a running, possibly unguarded loop.
- Pin the trailing termination re-raise in the agent-hooks function
  middleware: an inner short-circuit is bracketed and still propagates,
  skipping outer middleware post-code (test fails with the re-raise
  removed).

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>

* fix(core): acyclic tool-seam unwrap chain; document cooperative batch cancellation

Address two automated-review findings on the MiddlewareFailure PR,
both confirmed empirically:

- _reraise_tool_seam_block created a two-object exception-chain cycle
  (block.__cause__ -> wrapper -> block) by re-raising the chained
  InterceptionBlocked `from` its transport wrapper. Detach the
  wrapper's back-links and re-raise bare, recording the wrapper as
  the block's __context__ — acyclic, both exceptions still visible in
  tracebacks. Regression test walks the chain and pins finiteness
  (verified to fail against the cyclic re-raise).

- Batch cancellation is cooperative: a synchronous tool body already
  running in a worker thread (asyncio.to_thread) cannot be interrupted
  by task cancellation and may complete its side effects after the
  failure reached the caller; its result is discarded either way and
  propagation is not delayed behind it. Narrow the stated contract
  (MiddlewareFailure docstring, loop comment, spec 004) and pin it
  with a blocking-sync-sibling regression test.

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>

* fix(core): settle dangling calls on service-managed conversations on abort

Address maintainer review on the MiddlewareFailure PR:

- A MiddlewareFailure escaping a tool batch on a service-managed
  conversation left the hosted thread ending in unresolved
  function_call items: _update_continuation_state persists
  session.service_session_id when the model turn completes (before
  tool execution), and probe-verified the next run sends only the new
  user message against that conversation — OpenAI-style continuations
  reject such a request, so a routine policy abort left the session
  permanently stuck. Both loops now settle the thread before
  propagating: one error function_result per dangling call, submitted
  with tool_choice="none" in a single extra request whose response is
  discarded; a settlement failure never masks the abort, and runs
  without a service-managed conversation make no extra request.
  Pinned by three regression tests (non-streaming, streaming, and the
  no-conversation no-cost case); spec 004 and the MiddlewareFailure
  docstring updated.

- Make the three tool-bracket escape tuples in the agent-hooks
  function middleware identical (MiddlewareTermination,
  MiddlewareFailure, CancelledError): a MiddlewareFailure raised
  inside the post/error-bracket emit bodies is unreachable today, but
  the uniform tuples remove the need to reason about why they would
  differ, and preserve the exact exception (including the private
  tool-seam tag) if the emitter ever surfaces one.

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>

* fix(core): advance settled continuation; settle approved-replay aborts

Address maintainer review on the MiddlewareFailure settlement path,
both probe-verified (branch rebased onto current main first):

- Advance the persisted continuation to the settlement response. For
  response-ID continuations (OpenAI Responses store=True, where the
  response id is the continuation handle) the settlement response is
  the first endpoint whose chain includes the synthetic tool outputs;
  leaving session.service_session_id on the pre-settlement response
  made the settlement ineffective — the next run would continue from
  the still-unresolved turn. The settlement response now runs through
  _update_function_invocation_continuation_state (a no-op for stable
  conversation-object ids). Pinned by a regression test that fails
  with the advance removed.

- Cover the approval-resolution phase: a MiddlewareFailure raised
  while an approved tool is replayed escapes loudly (probe-verified,
  already the case) but executed before the loops' settlement seams,
  leaving the original — already service-persisted — call unresolved.
  _resolve_approval_responses now takes a settle_dangling_calls
  callback invoked with the approved batch on abort; the settlement
  helper became a layer method taking explicit calls
  (approval-response wrappers unwrap to their underlying calls,
  hosted-tool approvals are left to their provider protocol) and
  carries its own best-effort containment. Pinned by deny-during-
  replay regression tests in both response modes, mutation-verified.

Spec 004 invariants and matrix rows updated accordingly.

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>

---------

Signed-off-by: MohammadHaroonAbuomar <40180927+MohammadHaroonAbuomar@users.noreply.github.com>
2026-08-18 22:33:52 +00:00
..
2026-07-14 06:44:26 +00:00

Get Started with Microsoft Agent Framework for Python Developers

Quick Install

We recommend two common installation paths depending on your use case.

1. Development mode

If you are exploring or developing locally, install the entire framework with all sub-packages:

pip install agent-framework

This installs the core and every integration package, making sure that all features are available without additional steps. This is the simplest way to get started.

2. Selective install

If you only need specific integrations, you can install at a more granular level. This keeps dependencies lighter and focuses on what you actually plan to use. Some examples:

# Core only
# includes Azure OpenAI and OpenAI support by default
# also includes workflows and orchestrations
pip install agent-framework-core

# Core + Microsoft Foundry integration
pip install agent-framework-foundry

# Core + Microsoft Copilot Studio integration (preview package)
pip install agent-framework-copilotstudio --pre

# Core + both Microsoft Copilot Studio and Microsoft Foundry integration
pip install --pre agent-framework-copilotstudio agent-framework-foundry

This selective approach is useful when you know which integrations you need, and it is the recommended way to set up lightweight environments. Released packages such as agent-framework, agent-framework-core, and agent-framework-foundry no longer require --pre, while preview connectors such as agent-framework-copilotstudio still do.

Supported Platforms:

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

1. Setup API Keys

Set as environment variables, or create a .env file at your project root:

OPENAI_API_KEY=sk-...
OPENAI_MODEL=...
...
AZURE_OPENAI_API_KEY=...
AZURE_OPENAI_ENDPOINT=...
AZURE_OPENAI_MODEL=...
...
FOUNDRY_PROJECT_ENDPOINT=...
FOUNDRY_MODEL=...

For the generic OpenAI clients (OpenAIChatClient and OpenAIChatCompletionClient), configuration resolves in this order:

  1. Explicit Azure inputs such as credential or azure_endpoint
  2. OPENAI_API_KEY / explicit OpenAI API-key parameters
  3. Azure environment fallback such as AZURE_OPENAI_ENDPOINT and AZURE_OPENAI_API_KEY

This means mixed shells default to OpenAI when OPENAI_API_KEY is present. To force Azure routing, pass an explicit Azure input such as credential=AzureCliCredential().

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='',
    azure_endpoint='',
    model='',
    api_version='',
)

See the following setup guide 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

async def main():
    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 = await agent.run("Summarize the Three Laws of Robotics")
    print(result)

asyncio.run(main())
# 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 import Message
from agent_framework.openai import OpenAIChatClient

async def main():
    client = OpenAIChatClient()

    messages = [
        Message("system", ["You are a helpful assistant."]),
        Message("user", ["Write a haiku about Agent Framework."])
    ]

    response = await client.get_response(messages)
    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 pydantic import Field
from agent_framework import Agent
from agent_framework.openai import OpenAIChatClient


def get_weather(
    location: Annotated[str, Field(description="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.
    """

if __name__ == "__main__":
    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())

For more advanced orchestration patterns including Sequential, Concurrent, Group Chat, Handoff, and Magentic orchestrations, see the orchestration samples.

More Examples & Samples

Agent Framework Documentation