Python: add public TypedDict for AgentExecutor checkpoint state (#8201) - #8284
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…osoft#8201) Expose AgentExecutorCheckpointState / AgentSessionCheckpointState, validate restore field types, and cover partial/malformed/forward-compatible payloads.
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The root stub is unsynchronized, and validation does not fully enforce the published checkpoint schema.
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Pull request overview
Adds public checkpoint-state schemas for Python’s AgentExecutor, including restore validation and compatibility guidance.
Changes:
- Adds and exports two checkpoint
TypedDictcontracts. - Validates checkpoint fields during restoration.
- Adds schema, compatibility, and malformed-state tests.
File summaries
| File | Description |
|---|---|
test_agent_executor.py |
Tests checkpoint schemas and restoration behavior. |
_agent_executor.py |
Defines schemas and restore validation. |
__init__.py |
Exports the new public types. |
Review details
Suppressed comments (3)
python/packages/core/agent_framework/_workflows/_agent_executor.py:87
- Checking only
listdoes not validate the declared field types. For example,{"cache": ["bad"]}passes restore and is later sent torun_agentas though it containedMessageobjects; malformed pending responses similarly fail later when.typeis accessed instead of producing the promised checkpoint error. Validate each list element asMessageorContent, as appropriate.
list_keys = ("cache", "full_conversation", "pending_responses_to_agent")
for key in list_keys:
if key in state and state[key] is not None and not isinstance(state[key], list):
python/packages/core/agent_framework/_workflows/_agent_executor.py:93
- The mapping's declared
dict[str, Content]shape is not validated. A checkpoint with non-string keys or non-Contentvalues is accepted into_pending_agent_requests, which can leave pending requests that normal string request IDs can never remove. Validate both keys and values before restoring this field.
if "pending_agent_requests" in state and state["pending_agent_requests"] is not None:
if not isinstance(state["pending_agent_requests"], dict):
python/packages/core/agent_framework/_workflows/_agent_executor.py:100
- A dictionary is not sufficient for a valid
AgentSessionCheckpointState:session_idis required and must be a string. Payloads such as{}or{"session_id": 1}pass this check; the former is then caught and silently replaced with a new session, while the latter creates a session with an invalid ID. Validate the required nested field and raiseWorkflowCheckpointException.
if "agent_session" in state and state["agent_session"] is not None:
if not isinstance(state["agent_session"], dict):
- Files reviewed: 3/3 changed files
- Comments generated: 2
- Review effort level: Balanced
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| "AgentExecutorCheckpointState", | ||
| "AgentExecutorRequest", | ||
| "AgentExecutorResponse", | ||
| "AgentSessionCheckpointState", |
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Follow-up: synced agent_framework/__init__.pyi with the new root exports (AgentExecutorCheckpointState, AgentSessionCheckpointState, AgentSessionDict). See FOWEPJF255#1 (f016657).
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| type: NotRequired[str] | ||
| session_id: str | ||
| service_session_id: NotRequired[str | None] |
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Follow-up: AgentSessionDict.service_session_id is now str | ServiceSessionId | None, matching AgentSession.service_session_id / to_dict(). See FOWEPJF255#1.
| class AgentSessionCheckpointState(TypedDict): | ||
| """Serialized :class:`~agent_framework.AgentSession` payload (``AgentSession.to_dict()``). | ||
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| ``state`` holds session-local data. When the session uses service-side storage, | ||
| local ``state`` may be incomplete relative to the remote conversation. | ||
| """ | ||
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| type: NotRequired[str] | ||
| session_id: str | ||
| service_session_id: NotRequired[str | None] | ||
| state: NotRequired[dict[str, Any]] |
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can't we get this shape from the session itself, seems like a bad idea to maintain that twice
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Agreed — moved the shape onto AgentSession as AgentSessionDict (to_dict() return type) so AgentExecutor does not maintain a second copy. AgentSessionCheckpointState is an alias for the existing public name. Proposed in FOWEPJF255#1.
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| @override | ||
| async def on_checkpoint_restore(self, state: dict[str, Any]) -> None: | ||
| async def on_checkpoint_restore(self, state: AgentExecutorCheckpointState | dict[str, Any]) -> None: |
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why not just type this as the TypedDict, that's kind of the point, no?
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Updated: on_checkpoint_restore(self, state: AgentExecutorCheckpointState) — dropped the | dict[str, Any] union. Proposed in FOWEPJF255#1.
…wnership - Define AgentSessionDict on AgentSession (to_dict return) so the shape is not duplicated in AgentExecutor; keep AgentSessionCheckpointState as alias. - Include ServiceSessionId mapping in service_session_id. - Type on_checkpoint_restore as AgentExecutorCheckpointState only. - Sync root stub exports (__init__.pyi) with runtime __all__.
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Left a follow-up PR into your branch addressing the open review threads:
Changes:
Feel free to merge #1 into your branch (or cherry-pick |
…wnership (#1) - Define AgentSessionDict on AgentSession (to_dict return) so the shape is not duplicated in AgentExecutor; keep AgentSessionCheckpointState as alias. - Include ServiceSessionId mapping in service_session_id. - Type on_checkpoint_restore as AgentExecutorCheckpointState only. - Sync root stub exports (__init__.pyi) with runtime __all__.
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Merged the TypedDict ownership follow-up on the PR branch (FOWEPJF255#1). Ready for another look when you have a moment. |
…oft#8284) Enforce Message/Content element types, string pending-request keys, and required agent_session.session_id so malformed checkpoints fail at restore.
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Motivation & Context
Applications that inspect, migrate, or associate
AgentExecutorcheckpoint data currently rely on an undocumenteddict[str, Any]shape. A public TypedDict contract improves static analysis and makes checkpoint persistence safer to evolve.Fixes #8201.
Description & Review Guide
AgentExecutorCheckpointStateandAgentSessionCheckpointStateTypedDicts.on_checkpoint_save/on_checkpoint_restoreagainst that schema.WorkflowCheckpointException); accept missing keys and ignore unknown keys for compatibility.agent_frameworkand add unit tests.Related Issue
Fixes #8201
No other open PR targets this issue.
Contribution Checklist
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