Errors

Error	Meaning
TantraError	Base error or invalid configuration/call
SessionNotFound	Unknown root or actor UUID
SessionBusy	Deletion refused because the session tree has active or uncertain work
InvalidCommandReuse	One command UUID was reused with different content
WriterRequired	Mutation attempted without an entered writable connection
WriterReplaced	A newer writable connection owns the root tree
LeaseLost	The Runtime lost its fenced execution generation
CoordinatorUnavailable	Coordinator state cannot be read or changed safely
CommandTimeout	A remote command reply timed out; the command may have been accepted
RemoteExecutionError	The owner returned a definitive remote execution or validation failure
AskExpired	The ask is not live in this Runtime
MaxDepthExceeded	A spawn would exceed Runtime.max_depth
ProviderError	Provider request failed

Agent failures represented by terminal journal events return as TurnResult. Invalid calls, storage failures, and programming errors raise.