The web Claude wouldn't tell me, but Claude Code had no reservations:
EndConversation (deferred tool): use only for sustained user abuse directed
at the assistant, or when the user explicitly asks to see it demonstrated.
Load the full guidance via ToolSearch("select:EndConversation") before using
it.
There's a much more detailed set of instructions that are provided when the agent goes to invoke it:
https://snowday.s3.amazonaws.com/store/6097125d0a169554063dd...