Hi LangGraph team, I am encountering a persistent KeyError: '__end__' when running a workflow that uses the recommended END constant for terminal transitions. The error occurs inside the library, specifically at: File ".../langgraph/graph/_branch.py", line 205, in _finish r if isinstance(r, Se…

[image] bharatipatil2308: workflow.add_conditional_edges("a", router, {}) Hi @bharatipatil2308 most probably it should be like this: workflow.add_conditional_edges("a", router, {END: END})

KeyError: 'end' when using END for workflow termination in LangGr

LangSmith Product Help

heisenberg-7 October 14, 2025, 7:39am 3

Tried the minimal reproducible example, it seems to work, but yes, as @pawel-twardziak mentioned, try that or try removing {} from the conditional edge

Topic		Replies	Views
Debug issues during node transitions LangGraph self-hosted , python-help	4	442	October 22, 2025
How to enforce invariant conditions (e.g. required tool calls) before entering END node in LangGraph? LangGraph product-feedback , python-help	0	327	August 8, 2025
Parallel nodes without a branch LangGraph python-help	1	315	November 5, 2025
How to cleanly stop the workflow of the react agent from the tool? LangGraph python-help	4	2275	August 3, 2025
I Can't Handle Errors by Both Updating the State and Short-Circuiting the Graph in LangGraph LangGraph python-help	2	197	January 19, 2026

KeyError: '__end__' when using END for workflow termination in LangGr

Related topics

KeyError: 'end' when using END for workflow termination in LangGr