Python: [BREAKING] PR2 — Wire context provider pipeline, remove old types, update all consumers by eavanvalkenburg · Pull Request #3850 · microsoft/agent-framework

Eduard van Valkenburg (eavanvalkenburg) · 2026-02-11T15:06:38Z

Summary

Completes the context provider migration from ADR 0016. PR1 (#3763) added the new types side-by-side; this PR wires them into the agent execution flow, removes all old types, and updates every consumer.

What changed

Core agent wiring (`_agents.py`)

run() now accepts session: AgentSession | None instead of thread: AgentThread | None
New _prepare_session_and_messages() runs before_run on all context providers (forward order), assembles messages from SessionContext
New _finalize_response() / _run_after_providers() runs after_run on all providers (reverse order)
Auto-injects InMemoryHistoryProvider(source_id="memory") when: session is passed, no context providers on agent, no service_session_id, no response_id, store not True
create_session() and get_session(*, service_session_id=) (keyword-only) on SupportsAgentRun protocol
_RunContext uses session_messages (renamed from thread_messages)

Old types removed

Deleted: _threads.py (AgentThread), _memory.py (ContextProvider, ChatMessageStore, Context)
Deleted: old external provider files (_provider.py in redis/mem0, _search_provider.py in azure-ai-search, _chat_message_store.py in redis)
Deleted: corresponding old test files

External providers renamed

_RedisContextProvider → RedisContextProvider, _RedisHistoryProvider → RedisHistoryProvider
_Mem0ContextProvider → Mem0ContextProvider
_AzureAISearchContextProvider → AzureAISearchContextProvider

Lazy-loader stubs updated

redis/__init__.pyi: RedisChatMessageStore/RedisProvider → RedisContextProvider/RedisHistoryProvider
mem0/__init__.pyi: Mem0Provider → Mem0ContextProvider
redis/__init__.py_IMPORTS list updated

Session state serialization

Added Pydantic BaseModel support: models stored in session.state are auto-serialized via model_dump() and restored via model_validate() during to_dict()/from_dict() round-trips
New public API: register_state_type() for pre-registering types for cold-start deserialization

Lab/tau2

SlidingWindowChatMessageStore → SlidingWindowHistoryProvider(InMemoryHistoryProvider) with token-based truncation
runner.py reads full history from session.state["memory"]["messages"] instead of reaching into provider internals

DevUI

Migrated from AgentThread to plain list[Message] for internal message storage

Samples

Merged context_providers/ and sessions/ (née threads/) into single sessions/ folder
Removed aggregate_context_provider.py
Updated all ~54 sample files: AgentThread → AgentSession, get_new_thread() → create_session(), context_provider= → context_providers=[...], etc.
Fixed stale message_store, _notify_thread_of_new_messages, session_id.key references
UserInfoMemory sample refactored to use session.state instead of instance attributes
Updated all READMEs with new terminology

Tests

All tests updated for new API
Old test files removed
1597 core tests pass, 2969+ total pass

Fixes

Fixes#3587 — Rename AgentThread to AgentSession
Fixes#3588 — Add session management methods (create_session, get_session)
Fixes#3589 — Move serialize into the agent (AgentSession.to_dict()/from_dict())
Fixes#3590 — Orthogonal ChatMessageStore for service vs local (BaseHistoryProvider with load_messages/store_* flags)
Fixes#3601 — Rename ChatMessageStore to ChatHistoryProvider (BaseHistoryProvider)

Breaking changes

AgentThread removed — use AgentSession
ContextProvider / ChatMessageStore / Context removed — use BaseContextProvider / BaseHistoryProvider
agent.get_new_thread() → agent.create_session()
agent.get_new_thread(service_thread_id=X) → agent.get_session(service_session_id=X)
context_provider= (singular) → context_providers= (list)
chat_message_store_factory= → context_providers=[...]

File	Stmts	Miss	Cover	Missing
packages/a2a/agent_framework_a2a
_agent.py	169	9	94%	357, 378, 451–452, 493–494, 523–525
packages/ag-ui/agent_framework_ag_ui
_agent.py	36	1	97%	62
_client.py	151	17	88%	85–86, 90–94, 98–102, 265, 295, 464–466
_run.py	482	121	74%	156–163, 306, 325–326, 341–342, 357, 385–387, 412, 415–418, 420–421, 424–430, 433–435, 438, 454–456, 463, 469–471, 475, 480–482, 484–485, 501–505, 516, 529, 531–532, 548, 569–570, 625–627, 639–641, 839, 850–851, 858, 876–878, 912–914, 931, 937, 945, 947, 983–989, 992–995, 997–1006, 1009, 1017–1020, 1027, 1030–1031, 1036, 1042–1044, 1048, 1053–1056, 1070–1072
packages/azure-ai-search/agent_framework_azure_ai_search
_context_provider.py	265	131	50%	103–104, 224, 226, 230, 257–258, 260, 269–270, 273–274, 290, 300, 341–342, 355, 363–368, 371–373, 380–382, 387–390, 392–397, 399–405, 409, 413–418, 422, 424, 427–428, 430, 438–440, 443–445, 451, 453–455, 458, 471–472, 474–475, 477, 479–481, 487–488, 490–497, 499–503, 510, 512, 519, 524, 529, 531, 539–540, 542–543, 552, 554, 559, 561, 567–570, 577, 585, 592–594, 596–604, 606, 616–620, 623
packages/azure-ai/agent_framework_azure_ai
_agent_provider.py	116	1	99%	251
_chat_client.py	476	75	84%	387–388, 390, 573, 578–579, 581–582, 585, 588, 590, 595, 856–857, 859, 862, 865, 868–873, 876, 878, 886, 898–900, 904, 907–908, 916–919, 929, 937–940, 942–943, 945–946, 953, 961–962, 970–971, 976–977, 981–988, 993, 996, 1004, 1010, 1018–1020, 1023, 1045–1046, 1179, 1207, 1222, 1338, 1464
_client.py	212	22	89%	372, 374, 423, 452–457, 500, 535, 537, 570, 778, 781, 784–785, 787–790, 837
_project_provider.py	114	4	96%	212, 310, 354, 387
packages/azurefunctions/agent_framework_azurefunctions
_app.py	369	85	76%	204–205, 210–211, 322–323, 431, 439–440, 460–462, 468–470, 476–478, 511–512, 572–573, 622–623, 628, 710, 713, 722–724, 726–728, 730, 732, 743, 745–748, 750, 752–753, 755, 762–763, 765–766, 768–769, 771, 775, 785–787, 789–790, 792–794, 801, 803–804, 806, 827, 832, 844, 919, 929, 936–938, 983, 997, 1008–1010, 1012–1015, 1040, 1047, 1049, 1052
_orchestration.py	60	4	93%	129–130, 134, 149
packages/copilotstudio/agent_framework_copilotstudio
_agent.py	79	3	96%	169, 177, 294
packages/core/agent_framework
_agents.py	299	41	86%	476, 876, 912, 922–926, 1033–1035, 1105, 1147, 1160, 1173, 1179, 1215, 1217, 1226–1231, 1237, 1239, 1249–1250, 1257, 1259–1260, 1268–1272, 1280–1281, 1283, 1288, 1290
_clients.py	73	4	94%	307, 442, 505, 507
_mcp.py	406	64	84%	104–105, 115–120, 131, 136, 182–183, 193–198, 208–209, 261, 270, 333, 341, 362, 476, 543, 578, 580, 584–585, 587–588, 642, 657, 675, 716, 822, 835–840, 862, 899–900, 906–908, 927, 952–953, 957–961, 978–982, 1126
_middleware.py	329	16	95%	80, 83, 88, 795, 797, 799, 920, 947, 949, 974, 1055, 1059, 1183, 1187, 1248, 1322
_serialization.py	106	5	95%	291, 495, 511, 521, 589
_sessions.py	168	16	90%	77–79, 81–84, 101–102, 104–108, 549, 563
_settings.py	107	11	89%	93, 100, 116, 127, 143–144, 146, 149, 245–246, 251
_tools.py	755	86	88%	175–176, 306, 308, 326–328, 335, 353, 367, 379, 384, 386, 393, 430, 453–455, 504–506, 569, 591, 613–641, 676, 684, 925, 1187, 1244, 1248, 1327–1331, 1349, 1351–1352, 1464, 1468, 1518, 1520, 1536, 1538, 1602, 1629, 1686, 1754, 1933–1934, 1961, 1969, 1982, 1992–1993, 2028, 2084, 2116
_types.py	1026	96	90%	82, 91–92, 146, 151, 170, 172, 176, 180, 182, 184, 186, 204, 208, 234, 256, 261, 266, 270, 296, 300, 646–647, 1018, 1080, 1097, 1115, 1120, 1138, 1148, 1165–1166, 1168, 1186–1187, 1189, 1196–1197, 1199, 1234, 1245–1246, 1248, 1286, 1513, 1566, 1573, 1595, 1601, 1649, 1692–1697, 1719, 1724, 1890, 1902, 2145, 2154, 2175, 2270, 2495, 2702, 2772, 2784, 2791, 2802, 3006–3008, 3011–3013, 3017, 3022, 3026, 3138–3140, 3168, 3222, 3226–3228, 3230, 3241–3242, 3245–3249, 3255
exceptions.py	50	0	100%
observability.py	618	84	86%	335, 337–339, 342–344, 349–350, 356–357, 363–364, 371, 373–375, 378–380, 385–386, 392–393, 399–400, 407, 676, 679, 687–688, 691–694, 696, 699–701, 704–705, 733, 735, 746–748, 750–753, 757, 765, 866, 868, 1017, 1019, 1023–1028, 1030, 1033–1037, 1039, 1151–1152, 1154, 1211–1212, 1347, 1401–1402, 1518–1520, 1579, 1747, 1901, 1903
packages/core/agent_framework/_workflows
_agent.py	343	72	79%	59, 67–73, 109–110, 190, 233–235, 289–291, 336–337, 343–344, 350, 352, 357, 417–418, 427, 434, 460, 493–495, 497, 499, 501, 506, 511, 558, 588, 605, 644–647, 653, 659, 663–664, 667–673, 677–678, 684, 745, 752, 758–759, 770, 802, 809, 830, 839, 843, 845–847, 854
_agent_executor.py	184	24	86%	97, 145, 163–164, 216–217, 219–220, 250–252, 260–262, 270–272, 274, 278, 282, 286–287, 414, 432
packages/core/agent_framework/azure
_responses_client.py	51	6	88%	189, 221, 287–290
packages/core/agent_framework/openai
_assistant_provider.py	109	9	91%	172, 297, 363, 478–483
_responses_client.py	612	80	86%	294–297, 301–302, 305–306, 312–313, 318, 331–337, 358, 366, 389, 552, 555, 610, 614, 616, 618, 620, 696, 706, 711, 754, 813, 827, 844, 857, 913, 1006, 1011, 1015–1017, 1021–1022, 1045, 1114, 1136–1137, 1152–1153, 1171–1172, 1303–1304, 1320, 1322, 1401–1409, 1504, 1559, 1574, 1610–1611, 1613–1615, 1629–1631, 1641–1642, 1648, 1663
packages/mem0/agent_framework_mem0
_context_provider.py	79	1	98%	128
packages/orchestrations/agent_framework_orchestrations
_group_chat.py	328	70	78%	173, 336, 343, 372, 383–384, 390, 395, 416, 420, 433–434, 447, 462–463, 465, 481, 508–513, 515, 548–551, 553, 558–562, 650, 653, 692, 695, 698, 701, 709, 721–722, 724–725, 727–728, 730, 735, 738, 747, 753, 797–798, 802–803, 817–818, 820–821, 852–853, 919, 938, 946, 951–953, 960, 970
_handoff.py	326	56	82%	104–105, 107, 136–137, 159–169, 171, 173, 175, 180, 278, 331, 356, 384, 392–393, 407, 458–459, 491, 531–533, 538–540, 656, 659, 666, 671, 733, 738, 745, 755, 757, 776, 778, 860–861, 893–894, 976, 983, 1055–1056, 1058
_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, 1102–1103, 1107–1109, 1133, 1157–1158, 1171, 1187, 1209, 1257–1258, 1296–1297, 1460, 1463, 1472, 1475, 1480, 1531–1532, 1573–1574, 1622, 1652, 1710, 1724, 1735
packages/purview/agent_framework_purview
_middleware.py	112	0	100%
packages/redis/agent_framework_redis
_context_provider.py	178	56	68%	220, 238, 241, 247–248, 250–251, 253–255, 257–259, 261–263, 265–276, 278–279, 281–287, 315, 317, 321–326, 347, 358, 368–369, 382–383, 407, 409–410, 414–415
_history_provider.py	58	1	98%	174
TOTAL	20417	3248	84%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3903	225 💤	0 ❌	0 🔥	1m 9s ⏱️

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Tao Chen (TaoChenOSU) · 2026-02-11T21:34:21Z

Is this a breaking change?

- Replace AgentThread with AgentSession across all packages - Replace ContextProvider with BaseContextProvider across all packages - Replace context_provider param with context_providers (Sequence) - Replace thread= with session= in run() signatures - Replace get_new_thread() with create_session() - Add get_session(service_session_id) to agent interface - DurableAgentThread -> DurableAgentSession - Remove _notify_thread_of_new_messages from WorkflowAgent - Wire before_run/after_run context provider pipeline in RawAgent - Auto-inject InMemoryHistoryProvider when no providers configured

…, remove old test files

…tThread→AgentSession, ContextProvider→BaseContextProvider)

…rted sample)

…ion with session_id

…rate devui to use plain message lists

…ryProvider(InMemoryHistoryProvider)

…g into provider internals

…or new provider types

…session_id.key references in samples

…ssions, remove aggregate_context_provider

…tance attributes

Pydantic models stored in session.state are now automatically serialized via model_dump() and restored via model_validate() during to_dict()/from_dict() round-trips. Models are auto-registered on first serialization; use register_state_type() for cold-start deserialization. Also export register_state_type as a public API.

AsyncMemory (OSS) expects user_id/agent_id/run_id as direct kwargs, while AsyncMemoryClient (Platform) expects them in a filters dict. Adds tests for both client types. Port of fix from microsoft#3844 to new Mem0ContextProvider.

…int decode logic - Add back _conversation_state.py (encode/decode_chat_messages) lost in rebase - Fix on_checkpoint_restore to decode cache/conversation with decode_chat_messages - Fix on_checkpoint_restore to use decode_checkpoint_value for pending requests - Add tests/workflow/__init__.py for relative import support - Fix test_agent_executor checkpoint selection (checkpoints[1] not superstep)

…der injection Chat clients that store history server-side by default (OpenAI Responses API, Azure AI Agent) now declare STORES_BY_DEFAULT = True. The agent checks this during auto-injection and skips InMemoryHistoryProvider unless the user explicitly sets store=False.

…ead/ContextProvider API

… remove stale AGUIThread - Fix: Propagate conversation_id from ChatResponse back to session.service_session_id in both streaming and non-streaming paths in _agents.py - Rename AgentThreadException → AgentSessionException - Remove stale AGUIThread from ag_ui lazy-loader - Rename use_service_thread → use_service_session in ag-ui package - Rename test functions from *_thread_* to *_session_* - Rename sample files from *_thread* to *_session* - Update docstrings and comments: thread → session - Update _mcp.py kwargs filter: add 'session' alongside 'thread' - Fix ContinuationToken docstring example: thread=thread → session=session - Fix _clients.py docstring: 'Agent threads' → 'Agent sessions'

CopilotAI review requested due to automatic review settings February 11, 2026 15:06

Eduard van Valkenburg (eavanvalkenburg) requested a review from a team as a code owner February 11, 2026 15:06

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Eduard van Valkenburg (eavanvalkenburg)force-pushed the edvan/pr2-context-provider-pipeline branch from a25dbce to 5873923Compare February 11, 2026 15:11

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Eduard van Valkenburg (eavanvalkenburg) changed the title ~~Python: PR2 — Wire context provider pipeline, remove old types, update all consumers~~Python: [BREAKING] PR2 — Wire context provider pipeline, remove old types, update all consumersFeb 11, 2026

Eduard van Valkenburg (eavanvalkenburg) added the breaking change Usage: [PRs], Target: all PRs that introduce changes that are not backward compatible label Feb 11, 2026

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Eduard van Valkenburg (eavanvalkenburg) added 15 commits February 12, 2026 19:29

fix: update all tests for context provider pipeline, fix lazy-loaders…
b10e71a
…, remove old test files

refactor: update all sample files for context provider pipeline (Agen…
6e9d6df
…tThread→AgentSession, ContextProvider→BaseContextProvider)

fix: update remaining ag-ui references (client docstring, getting_sta…
7d71e8f
…rted sample)

fix: make get_session service_session_id keyword-only to avoid confus…
7edb857
…ion with session_id

refactor: rename _RunContext.thread_messages to session_messages
c6c0d72

refactor: remove _threads.py, _memory.py, and old provider files; mig…
c65254c
…rate devui to use plain message lists

rename: remove _new_ prefix from test files
cf4cb17

refactor: rewrite SlidingWindowChatMessageStore as SlidingWindowHisto…
bf3725c
…ryProvider(InMemoryHistoryProvider)

fix: read full history from session state directly instead of reachin…
0eaac4f
…g into provider internals

fix: update stale .pyi stubs, sample imports, and README references f…
3510e06
…or new provider types

fix: remove stale message_store, _notify_thread_of_new_messages, and …
111959a
…session_id.key references in samples

refactor: merge context_providers and sessions sample folders into se…
f60b19a
…ssions, remove aggregate_context_provider

refactor: UserInfoMemory stores state in session.state instead of ins…
b42159d
…tance attributes

Eduard van Valkenburg (eavanvalkenburg) added 3 commits February 12, 2026 19:34

Eduard van Valkenburg (eavanvalkenburg)force-pushed the edvan/pr2-context-provider-pipeline branch from 46397c5 to c983448Compare February 12, 2026 18:34

Fix broken markdown links in azure_ai and redis READMEs
0437ffd

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Comment threadpython/packages/core/agent_framework/_workflows/_agent.py Outdated

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Comment threadpython/packages/core/agent_framework/_workflows/_conversation_state.py Outdated

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Eduard van Valkenburg (eavanvalkenburg) added 3 commits February 12, 2026 19:52

Fix getting-started samples to use session API instead of removed thr…
fcd2cb0
…ead/ContextProvider API

updates to workflow as agent
9b4df38

fix group chat import
39afa96

Tao Chen (TaoChenOSU) reviewed Feb 12, 2026
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Comment threadpython/packages/core/agent_framework/_workflows/_agent.py

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Fix broken markdown links after thread→session file renames
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fix azure ai test
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Merged via the queue into microsoft:main with commit 1e350eaFeb 12, 2026
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Agent with tools fails: "Object of type function is not JSON serializable" #3903
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Python: Fix RedisProvider HybridQuery compatibility with redisvl 0.14.0 #3880
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Python: [Bug]: can't import ChatMessageStore in 1.2.2 #5700
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Python: add ChatMessageStore backward-compat alias for HistoryProvider (fixes #5700) #6189
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Python: [BREAKING] PR2 — Wire context provider pipeline, remove old types, update all consumers - #3850

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Eduard van Valkenburg (eavanvalkenburg) commented Feb 11, 2026

Summary

What changed

Core agent wiring (_agents.py)

Old types removed

External providers renamed

Lazy-loader stubs updated

Session state serialization

Lab/tau2

DevUI

Samples

Tests

Fixes

Breaking changes

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Core agent wiring (`_agents.py`)

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