A bit of background:
I'm trying to emulate the behavior of the default "New" button w.r.t. automatically setting the parent object in the new object form. So, for instance, if I click the "new opportunity" button from the opportunity related list on the account screen, the account is prepopulated for me because the URL it creates is "006/e?retURL=%2F001A0000010o2zs&accid=001A0000010o2zs" (i.e. has a reference to the account ID).
This works with custom objects, too, but the "prepopulate" field is of the form "CF00NA000000AGyU2=Burlington+Textiles+Company&CF00NA000000AGyU2_lkid=001A0000010o2zs" where CF00NA000000AGyU2 is a random identifier assigned by Salesforce to the account lookup field. There doesn't seem to be a way to query that value through the metadata API, but I can do it through the tooling API via:
/services/data/v29.0/tooling/query?q=SELECT+Id,DeveloperName,NamespacePrefix+FROM+CustomObject+WHERE+DeveloperName='Order'+AND+NamespacePrefix='XX_ORD1'
and then:
/services/data/v29.0/tooling/query?q=SELECT+Id,DeveloperName,NamespacePrefix,TableEnumOrId,FullName,Metadata+FROM+CustomField+WHERE+DeveloperName='AccountLookup'+AND+NamespacePrefix='XX_ORD1'+AND+TableEnumOrId='(fill in value from prior call)'
My question:
It works OK (besides being a bit slow) most of the time, but when a platform user tries to invoke it, I get the error message in the title:
[{"message":"sObject type 'CustomEntityDefinition' is not supported.","errorCode":"INVALID_TYPE"}]
I can't find any documentation indicating that platform users can't use the tooling API; I've verified that they can use the other REST APIs. Is there some profile setting I need to enable for this? The documentation is pretty sparse; it just talks about how to use the tooling API, not how to enable it. I definitely have "API enabled" for the profile in question.
