disabling Sub-agent configuration file

The suggested template for implementing a sub-agent, uses
init_snmp("[agent_name]").
A agent_name.conf configuration file is created (in /var/net-snmp/).
 
1) What is the agent_name parameter used for except the configuration
file name?
2) What is the oldEngineId used for?
3) Is this file absulutly neccesary? (say I don't care about the boots
count)
4) Can I restrict the file size? (to make sure it doesn't inflate and
overuse disk space - on embedded system)
 
 
thanks,
Erez Makavy