If you would like to report which tickets have been closed with one message from the agent you can use the DPQL below:

SELECT tickets_messages.ticket.id, tickets_messages.ticket.subject
FROM tickets_messages
WHERE tickets_messages.ticket.count_agent_replies = '1' AND tickets_messages.person.is_agent = 1 AND tickets_messages.date_created = %LAST_WEEK% AND tickets_messages.is_agent_note = 0
SPLIT BY tickets_messages.person
ORDER BY tickets_messages.date_created 

This will split the results out by each agent and show details for each ticket that was quickly resolved by the agent.