Python: (ag-ui): fix Workflow.as_agent() streaming regression

[moonbox3]

Motivation and Context

add_agent_framework_fastapi_endpoint failed for workflow-backed agents because AG-UI tried to await an async generator returned by WorkflowAgent.run(stream=True).

In #3379, AG-UI switched to agent.run(stream=True) and assumed streaming results were either:

• ResponseStream, or
• Awaitable[ResponseStream]

But WorkflowAgent.run(stream=True) returns an AsyncIterable (async generator), which is not awaitable.

What changed

• Added stream normalization in AG-UI to accept:
  • ResponseStream
  • AsyncIterable
  • Awaitable resolving to either
• Updated run_agent_stream to use this normalization before iterating.
• Kept strict typing clean in _run.py (pyright/mypy-safe).

Tests
Added regression coverage for both unit and endpoint paths:

• _normalize_response_stream accepts async-iterable streams and rejects invalid values.
• FastAPI endpoint test with a SupportsAgentRun implementation returning an async generator for stream=True.

Description

• Fixes Python: [Bug]: WorkflowAgent incompatible with add_agent_framework_fastapi_endpoint - streaming interface mismatch #3853
• Fixed other Pyright typing issues previously present

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/ag-ui/agent_framework_ag_ui
_run.py	510	123	75%	156–163, 209–210, 217, 340, 359–360, 375–376, 391, 419–421, 446, 449–452, 454–455, 458–464, 467–469, 472, 488–490, 497, 503–505, 509, 514–516, 518–519, 535–539, 550, 562, 566, 568–569, 585, 612–613, 668–670, 682–684, 887, 898–899, 906, 955–957, 974, 980, 988, 990, 998, 1028–1034, 1037–1040, 1042–1051, 1054, 1062–1065, 1072, 1075–1076, 1081, 1087–1089, 1093, 1098–1101, 1115–1117
TOTAL	20445	3244	84%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3908	225 💤	0 ❌	0 🔥	1m 10s ⏱️

[Copilot]

Pull request overview

Fixes a streaming regression in the Python AG-UI integration so workflow-backed agents (e.g., Workflow.as_agent()) that return an async generator for run(stream=True) can be streamed correctly through add_agent_framework_fastapi_endpoint.

Changes:

• Added _normalize_response_stream in agent_framework_ag_ui/_run.py to accept ResponseStream, AsyncIterable, or an Awaitable resolving to either.
• Updated run_agent_stream to normalize streaming outputs before iterating.
• Added regression tests covering both the normalization helper and a FastAPI endpoint path using an async-generator streaming agent.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
python/packages/ag-ui/agent_framework_ag_ui/_run.py	Normalizes agent streaming return types and updates streaming execution path; includes some additional typing-safety adjustments.
python/packages/ag-ui/tests/ag_ui/test_run.py	Adds unit tests for _normalize_response_stream (accept async iterables, reject invalid values).
python/packages/ag-ui/tests/ag_ui/test_endpoint.py	Adds endpoint regression test ensuring FastAPI streaming works when run(stream=True) returns an async generator.