Python: [Bug]: Thread State Serialization Breaks Multi-Turn Tool Calls

[sphenry]

Description

agent.deserialize_thread() loses fc_id ↔ call_id mapping, causing "No tool call found" errors on restored sessions. very multi-turn conversation creates a new thread per turn, increasing token usage and losing native thread continuity.

A workaround is to have a built in-memory ConversationStore that injects history as prompt text prefix instead of restoring thread state

Code Sample

Error Messages / Stack Traces

Package Versions

1.0.0rc4

Python Version

No response

Additional Context

No response

[eavanvalkenburg]

I have a fix up in PR #4684:

• Python: fix thread serialization for multi-turn tool calls #4684

The change keeps stored Responses fc_id values intact in session history, but stops replaying those stale response-scoped IDs when provider-attributed history is resent through the Responses API. The fix lives in the Responses client boundary instead of framework-wide session/history loading, still preserves live same-run fc_id behavior for active tool loops, and includes integration coverage for the persisted-session replay path.