Buyers agent commission split

[Josh Jacobsen]

Hi friends, 

An agent in my office asked me to show his client a house. I did, and then helped write an offer on the property. Since then, the original agent has handled the counters and remaining paperwork. He wants to compensate me, but neither of us really have a gauge on what is fair in this situation.  Can anybody speak from experience on what they've done in similar situations?