Python: [BREAKING] Removed context parameter from call_next

[dmytrostruk]

Motivation and Context

Resolves: #3584

Removed context parameter from call_next middleware callable.

Before:

await call_next(context)

After:

await call_next()

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.

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework
_middleware.py	329	16	95%	80, 83, 88, 795, 797, 799, 920, 947, 949, 974, 1055, 1059, 1183, 1187, 1248, 1322
packages/orchestrations/agent_framework_orchestrations
_handoff.py	326	56	82%	104–105, 107, 136–137, 159–169, 171, 173, 175, 180, 278, 332, 357, 385, 393–394, 408, 459–460, 492, 532–534, 539–541, 657, 660, 667, 672, 734, 739, 746, 756, 758, 777, 779, 861–862, 894–895, 977, 984, 1056–1057, 1059
packages/purview/agent_framework_purview
_middleware.py	112	0	100%
TOTAL	16901	2109	87%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
4015	225 💤	0 ❌	0 🔥	1m 11s ⏱️

[Copilot]

Pull request overview

This PR implements the breaking API change requested in #3584 by simplifying Python middleware chaining so call_next is invoked as await call_next() (no context parameter), and updates the core middleware pipeline, tests, and samples accordingly.

Changes:

• Update core middleware type aliases, wrappers, and pipeline execution to use call_next: Callable[[], Awaitable[None]].
• Update all Python samples/docs to call await call_next() instead of await call_next(context).
• Update unit tests across core/purview/ollama/orchestrations to match the new middleware signature.

Reviewed changes

Copilot reviewed 29 out of 29 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
python/packages/core/agent_framework/_middleware.py	Changes middleware callable types and pipeline next handler construction to remove the context parameter.
python/packages/core/AGENTS.md	Updates middleware usage example to await call_next().
python/packages/core/tests/core/test_middleware.py	Updates middleware pipeline tests to use the new call_next() signature.
python/packages/core/tests/core/test_middleware_with_agent.py	Updates agent middleware tests to use call_next() with no args.
python/packages/core/tests/core/test_middleware_with_chat.py	Updates chat middleware tests to use call_next() with no args.
python/packages/core/tests/core/test_middleware_context_result.py	Updates context/result middleware behavior tests for the new call_next() signature.
python/packages/core/tests/core/test_function_invocation_logic.py	Updates function middleware tests that previously called next_handler(context) to next_handler().
python/packages/core/tests/core/test_as_tool_kwargs_propagation.py	Updates agent middleware used in as-tool kwargs propagation tests to call_next().
python/packages/purview/agent_framework_purview/_middleware.py	Updates Purview middleware process signatures to accept call_next() with no args.
python/packages/purview/tests/test_middleware.py	Updates Purview agent middleware tests to provide mock_next() without a context parameter.
python/packages/purview/tests/test_chat_middleware.py	Updates Purview chat middleware tests to provide mock_next() without a context parameter.
python/packages/orchestrations/agent_framework_orchestrations/_handoff.py	Updates handoff middleware to call await call_next() when not intercepting.
python/packages/ollama/tests/test_ollama_chat_client.py	Updates sample chat middleware test to call await call_next().
python/samples/getting_started/middleware/thread_behavior_middleware.py	Updates sample middleware signature and invocation to call_next().
python/samples/getting_started/middleware/shared_state_middleware.py	Updates sample function middleware signatures and invocations to call_next().
python/samples/getting_started/middleware/runtime_context_delegation.py	Updates middleware samples (including decorators) to call call_next() without context.
python/samples/getting_started/middleware/override_result_with_middleware.py	Updates chat/agent middleware samples to call call_next() without context.
python/samples/getting_started/middleware/middleware_termination.py	Updates middleware signatures to call_next() and hardens sample printing when result may be None.
python/samples/getting_started/middleware/function_based_middleware.py	Updates middleware signatures to call_next() and hardens sample printing when result may be None.
python/samples/getting_started/middleware/exception_handling_with_middleware.py	Updates function middleware signature and invocation to call_next().
python/samples/getting_started/middleware/decorator_middleware.py	Updates decorator middleware examples to call call_next() without context.
python/samples/getting_started/middleware/class_based_middleware.py	Updates class-based middleware signatures to accept call_next() with no args.
python/samples/getting_started/middleware/chat_middleware.py	Updates chat middleware samples to call call_next() with no args.
python/samples/getting_started/middleware/agent_and_run_level_middleware.py	Updates agent/run-level middleware samples to call call_next() and hardens sample printing when result may be None.
python/samples/getting_started/devui/weather_agent_azure/agent.py	Updates chat/function middleware in devui sample to call call_next() without context.
python/samples/getting_started/agents/openai/openai_responses_client_with_agent_as_tool.py	Updates function middleware sample to call call_next() without context.
python/samples/getting_started/agents/openai/openai_responses_client_basic.py	Updates chat middleware sample to call call_next() without context.
python/samples/getting_started/agents/azure_ai/azure_ai_with_agent_as_tool.py	Updates function middleware sample to call call_next() without context.
python/samples/concepts/tools/README.md	Updates documentation examples and explanatory text to reflect call_next() without a context argument.

Comments suppressed due to low confidence (2)

python/packages/purview/agent_framework_purview/_middleware.py:168

• # type: ignore[override] on this override appears unnecessary now that ChatMiddleware.process accepts call_next: Callable[[], Awaitable[None]]. Consider removing it so static type checking can flag actual override issues.

    async def process(
        self,
        context: ChatContext,
        call_next: Callable[[], Awaitable[None]],
    ) -> None:  # type: ignore[override]

python/packages/core/tests/core/test_middleware_with_agent.py:1716

• This statement is unreachable.

                await call_next()