How do I set the caller-id that the agent receives?

You may often want to set the Caller ID of the call when sent to the agent to something that makes sense to the agent - for example, the number just called, or the name of the person called, or the name of your campaign.

In order to do this, you need to intercept the call before it is sent to your queue and rewrite the Caller ID. Consider that all the attributes you set on the call are available as channel variables in Asterisk, so you can set any attributes you want the agent to see.

For example, imagine that your queue 999 is located at extension 999@from-internal. Instead of sending connected calls to that extension, you could create a piece of dialplan to do the rewriting and the jump to that extension, like for example: [wbt-rewrite]
exten => 999,1,Answer
exten => 999,n,Set(CALLERID(num)=#${ID} ${PERS})
exten => 999,n,Goto(from-internal,999,1)
In this case, you have the Wombat send successful calls to 999@wbt-rewrite, where Asterisk rewrites the Caller ID and then jumps to 999@from-internal.

A more complex version of this example - using a micro CRM broker - is available on WombatDialer and QueueMetrics.