Hier ein kleiner Auszug aus der Hilfe zu "UnprocessedDocuments"
For agents that run on new and modified documents, newly received mail documents, pasted documents, or newly modified documents, you must use the UpdateProcessedDoc method in NotesSession to mark each document as "processed," which ensures that a document gets processed by the agent only once (unless it's modified, mailed, or pasted again). If you do not call this method for each document, the agent processes the same documents the next time it runs.