Description: I’m encountering a persistent InvalidUpdateError when attempting to update thread state in LangGraph API v0.4.20. The error occurs during state updates and suggests that a node named __copy__ doesn’t exist in my graph definition. This is happening with langgraph dev –allow-blocking and…

InvalidUpdateError: Node copy does not exist - LangGraph State Update Failure

catherine-langchain September 16, 2025, 1:11am 2

hey @Petar - would it be possible to share a minimally reproducible example?

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