Python: Fixed middleware and multimodal input samples

[dmytrostruk]

Motivation and Context

• Fixed runtime kwargs propagation from agent.run() to FunctionInvocationContext.kwargs in function middleware — kwargs like user_id were silently dropped and never reached middleware
• Fixed get_response() calls in multimodal input samples to pass [message] (list) instead of message (single object), which caused TypeError: 'Message' object is not iterable
• Fixed streaming branch in weather override middleware sample (replace broken _update_hook with proper AsyncIterable stream override, fixed Role.ASSISTANT → "assistant")
• Fixed exception handling middleware sample (tuple literal had trailing comma creating a tuple instead of string concatenation)

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
_agents.py	323	42	87%	425, 429, 481, 846, 882, 959–962, 1023–1025, 1146, 1162, 1164, 1177, 1183, 1219, 1221, 1230–1235, 1240, 1242, 1248–1249, 1256, 1258–1259, 1267–1268, 1271–1273, 1281–1282, 1284, 1289, 1291
_types.py	998	87	91%	49, 58–59, 113, 118, 137, 139, 143, 147, 149, 151, 153, 171, 175, 201, 223, 228, 233, 237, 263, 267, 613–614, 985, 1047, 1064, 1082, 1087, 1105, 1115, 1132–1133, 1135, 1153–1154, 1156, 1163–1164, 1166, 1201, 1212–1213, 1215, 1253, 1480, 1532, 1623–1628, 1650, 1655, 1821, 1833, 2076, 2085, 2106, 2201, 2426, 2633, 2703, 2715, 2733, 2931–2933, 2936–2938, 2942, 2947, 2951, 3035–3037, 3066, 3120, 3139–3140, 3143–3147, 3153
TOTAL	21168	3322	84%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
4164	239 💤	0 ❌	0 🔥	1m 12s ⏱️

[Copilot]

Pull request overview

This PR fixes critical bugs in Python middleware and multimodal input samples that would have caused runtime failures.

Changes:

• Fixed runtime kwargs propagation from agent.run() to FunctionInvocationContext.kwargs in function middleware - kwargs like user_id were silently dropped
• Fixed get_response() API calls in three multimodal input samples to pass [message] (list) instead of message (single object), preventing TypeError: 'Message' object is not iterable
• Fixed streaming override in weather middleware sample by replacing broken with_transform_hook approach with proper AsyncIterable stream override and correcting Role.ASSISTANT → "assistant"
• Fixed exception handling middleware where tuple literal had trailing comma creating a tuple instead of string concatenation

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
python/packages/core/agent_framework/_agents.py	Merges runtime kwargs into additional_function_arguments to propagate them to function middleware
python/packages/core/agent_framework/_types.py	Cosmetic formatting change to tools type annotation (single line instead of multi-line)
python/packages/core/tests/core/test_middleware_with_agent.py	Adds 4 comprehensive tests for kwargs propagation behavior
python/samples/02-agents/middleware/override_result_with_middleware.py	Fixes streaming override logic and removes non-existent Role enum usage
python/samples/02-agents/middleware/exception_handling_with_middleware.py	Fixes tuple literal bug by removing trailing comma for proper string concatenation
python/samples/02-agents/multimodal_input/openai_chat_multimodal.py	Fixes get_response() calls to pass list of messages and updates comment
python/samples/02-agents/multimodal_input/azure_responses_multimodal.py	Fixes get_response() calls to pass list of messages and updates comment
python/samples/02-agents/multimodal_input/azure_chat_multimodal.py	Fixes get_response() calls to pass list of messages and updates comment