I agree with @Gerry O'Rourke here. The docs gave me false hope, but sadly, looks like UCCE continues to not support POSTing agents, only packaged UCCE supports creating agents via POST requests. 

Following up here - Cisco Bug has been identified and opened:CSCvn01600https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvn01600  

@dstaudt Button 1 is a FIXED button type and is therefor not required.I just tried with your suggestion of providing button 1 anyway, and I get the same result.Opened a TAC case 路‍

Here is an example of a Phone template being created for an 8851: <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> <soapenv:Header/> <soapenv:Body> <ns2:addPhoneButtonTemplate xmlns:ns2="http://www.cisco.co...

Hey @Nathan Richardson , were you ever able to resolve this? We are also noticing this problem on CUCM 12.5