A stored host message to admit at an execution checkpoint.
source_id identifies one message across retries. source_sequence orders
messages within the conversation. actor records the author as JSON data;
it does not grant tool permissions. message must have the user role.
Summary
Types
@type t() :: %Agentix.SourceInput{ actor: map(), message: ReqLLM.Message.t(), source_id: String.t(), source_sequence: non_neg_integer() }