[BREAKING] Python: Remove workflow register factory methods. Update tests and samples

[moonbox3]

Motivation and Context

Remove workflow register factory methods in favor of creating a helper method with executor/agent instances + workflow builder.

Description

• Remove workflow factory methods
• Update tests
• Update samples
• Closes Python: Remove workflow factory methods from WorkflowBuilder in favor of a helper instantiation method #3784

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/_workflows
_workflow_builder.py	137	9	93%	171, 448–452, 454, 557, 572
packages/orchestrations/agent_framework_orchestrations
_concurrent.py	155	27	82%	51, 60–61, 69–70, 89–90, 95, 122, 127, 132–133, 139, 161, 171, 178, 245, 261, 264, 321, 351, 353–354, 356, 361, 374, 378
_group_chat.py	266	49	81%	175, 338, 345, 374, 385–386, 392, 397, 413, 440–445, 447, 480–483, 485, 490–494, 615, 618, 621, 624, 632, 642, 651, 657, 701–702, 706–707, 721–722, 724–725, 756–757, 823, 842, 850, 857, 867
_handoff.py	326	56	82%	104–105, 107, 136–137, 159–169, 171, 173, 175, 180, 280, 334, 359, 387, 395–396, 410, 461–462, 494, 534–536, 541–543, 661, 664, 671, 676, 738, 743, 750, 760, 762, 781, 783, 865–866, 898–899, 981, 988, 1060–1061, 1063
_magentic.py	585	96	83%	63–72, 77, 81–92, 257, 268, 272, 292, 353, 362, 364, 406, 423, 432–433, 435–437, 439, 450, 592, 594, 634, 682, 718–720, 722, 730–733, 737–740, 801–804, 895, 901, 907, 949, 987, 1019, 1036, 1047, 1104–1105, 1109–1111, 1135, 1159–1160, 1173, 1189, 1211, 1259–1260, 1298–1299, 1462, 1465, 1474, 1477, 1482, 1533–1534, 1575–1576, 1624, 1654, 1712, 1726, 1737
_sequential.py	86	11	87%	73, 166, 177, 183, 214, 216–217, 219, 224, 237, 241
TOTAL	16323	2014	87%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3862	225 💤	0 ❌	0 🔥	1m 10s ⏱️

[Copilot]

Pull request overview

Removes the Python workflow “factory registration” APIs (and related participant factory patterns in orchestrations) in favor of building workflows directly from executor/agent instances, and updates tests/samples to match.

Changes:

• Removed WorkflowBuilder.register_executor/register_agent and string-based node wiring; workflows are now wired with executor/agent instances.
• Removed participant_factories support from orchestration builders (Sequential/Concurrent/GroupChat/Magentic/Handoff) and updated tests accordingly.
• Updated (and in a few cases removed) getting-started samples that previously demonstrated factory-based patterns.

Reviewed changes

Copilot reviewed 46 out of 46 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
python/samples/getting_started/workflows/visualization/concurrent_with_visualization.py	Updates sample to build workflow from executor/AgentExecutor instances.
python/samples/getting_started/workflows/state-management/state_with_agents.py	Updates sample to use direct agent instances and direct edge wiring.
python/samples/getting_started/workflows/parallelism/map_reduce_and_visualization.py	Updates map/reduce sample to instantiate executors directly and wire by instance.
python/samples/getting_started/workflows/parallelism/fan_out_fan_in_edges.py	Updates fan-out/fan-in sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/parallelism/aggregate_results_of_different_types.py	Updates sample to instantiate executors directly and wire by instance.
python/samples/getting_started/workflows/control-flow/workflow_cancellation.py	Updates sample to wire @executor instances directly (no registration).
python/samples/getting_started/workflows/control-flow/switch_case_edge_group.py	Updates switch/case sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/control-flow/simple_loop.py	Updates loop sample to use AgentExecutor instance and instance wiring.
python/samples/getting_started/workflows/control-flow/sequential_streaming.py	Updates sequential streaming sample to wire executors by instance.
python/samples/getting_started/workflows/control-flow/sequential_executors.py	Updates sample to instantiate executors and wire by instance.
python/samples/getting_started/workflows/control-flow/multi_selection_edge_group.py	Updates multi-selection sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/control-flow/edge_condition.py	Updates conditional routing sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/composition/sub_workflow_request_interception.py	Updates sub-workflow composition sample to instantiate executors directly.
python/samples/getting_started/workflows/composition/sub_workflow_parallel_requests.py	Updates sub-workflow parallel request sample to instantiate executors directly.
python/samples/getting_started/workflows/composition/sub_workflow_basics.py	Updates basic sub-workflow composition sample to use direct instances.
python/samples/getting_started/workflows/checkpoint/workflow_as_agent_checkpoint.py	Updates SequentialBuilder usage to pass participant instances (no factories).
python/samples/getting_started/workflows/checkpoint/sub_workflow_checkpoint.py	Updates checkpointing sample to instantiate executors directly and wire by instance.
python/samples/getting_started/workflows/checkpoint/checkpoint_with_resume.py	Updates checkpoint resume sample to instantiate executors directly and wire by instance.
python/samples/getting_started/workflows/checkpoint/checkpoint_with_human_in_the_loop.py	Updates HITL checkpoint sample to use AgentExecutor instance and instance wiring.
python/samples/getting_started/workflows/agents/workflow_as_agent_with_thread.py	Updates SequentialBuilder usage to pass agent instances (no factories).
python/samples/getting_started/workflows/agents/workflow_as_agent_reflection_pattern.py	Updates workflow-as-agent sample to instantiate executors directly.
python/samples/getting_started/workflows/agents/workflow_as_agent_human_in_the_loop.py	Updates workflow-as-agent HITL sample to instantiate executors directly.
python/samples/getting_started/workflows/agents/azure_chat_agents_tool_calls_with_feedback.py	Updates agent-to-agent workflow sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/agents/azure_ai_agents_with_shared_thread.py	Updates shared-thread sample to use AgentExecutor instances and instance wiring.
python/samples/getting_started/workflows/_start-here/step4_using_factories.py	Removes factory-focused “start here” step sample.
python/samples/getting_started/workflows/_start-here/step1_executors_and_edges.py	Adds helper-function guidance for state isolation now that factories are removed.
python/samples/getting_started/orchestrations/sequential_participant_factory.py	Removes orchestration sample demonstrating participant factories.
python/samples/getting_started/orchestrations/handoff_participant_factory.py	Removes orchestration sample demonstrating participant factories.
python/samples/getting_started/orchestrations/concurrent_participant_factory.py	Removes orchestration sample demonstrating participant factories.
python/packages/orchestrations/tests/test_sequential.py	Removes participant factory tests and updates assertions for participants-only behavior.
python/packages/orchestrations/tests/test_magentic.py	Removes participant factory tests and updates builder validation expectations.
python/packages/orchestrations/tests/test_handoff.py	Removes participant factory tests and updates validation expectations.
python/packages/orchestrations/tests/test_group_chat.py	Removes participant factory tests and updates validation expectations.
python/packages/orchestrations/tests/test_concurrent.py	Removes participant factory and aggregator-factory tests; updates for participants-only behavior.
python/packages/orchestrations/agent_framework_orchestrations/_sequential.py	Removes participant_factories support; requires participants.
python/packages/orchestrations/agent_framework_orchestrations/_magentic.py	Removes participant_factories support; requires participants.
python/packages/orchestrations/agent_framework_orchestrations/_handoff.py	Removes factory-based participant APIs; updates handoff wiring to instance-only.
python/packages/orchestrations/agent_framework_orchestrations/_group_chat.py	Removes participant_factories support; requires participants.
python/packages/orchestrations/agent_framework_orchestrations/_concurrent.py	Removes participant_factories and custom aggregator factory registration; requires participants.
python/packages/declarative/tests/test_graph_workflow_integration.py	Updates executor count expectations due to declarative entry node.
python/packages/declarative/tests/test_graph_coverage.py	Updates tests to construct WorkflowBuilder with a real executor instance.
python/packages/declarative/agent_framework_declarative/_workflows/_declarative_builder.py	Introduces a stable _workflow_entry node and wires it to the first action.
python/packages/core/tests/workflow/test_workflow_observability.py	Updates tracing test to reflect start executor is now an instance, not a string.
python/packages/core/tests/workflow/test_workflow_builder.py	Rewrites tests to use direct executor/agent instances (no registration APIs).
python/packages/core/tests/workflow/test_workflow_agent.py	Updates tests to build workflows directly from executor/agent instances.
python/packages/core/agent_framework/_workflows/_workflow_builder.py	Removes factory registration APIs and string-based wiring; requires instance-based wiring.