It's not really an Agent Issue, but there is no zabbix_sender component....
Basically, we have a daemon transforming JAVA JMX metric into Zabbix values and send it Zabbix with the Sender protocol. The problem is that the Server will process the values and report an overall success ratio (40 success, 60 failed), without logging on the server side (checked trunk and branch 1.8) or reporting to the sender (tcpdump shows no detail returned) the exact list of items that failed.
That feature would be extremely helpful in finding out what Items was missed in the configuration of the template in Zabbix and the completion of the Monitoring. Eventually, we'd like to obtain a 100% success ratio on the Zabbix Sender.
I'm unsure if it would be better to log the failed item on the server side (could be noisy, and it's technically the client's fault for sending something incorrect), or sending that list to the Sender as Text after the summary report so the Sender can parse it and log it locally.