the filter syntax is described on page 28 onwards, but there are a lot of caveats around shellvars, escaping and variable formatting.
You probably want a data filter, so something like below - note liberal use of escaping on the double quotes because I am passing in SID and MC as shellvars (cant use single quote), also need to escape the $ in the operator and also -g to stop curl processing the [ ]'s
root@kali:/home/aruba/curl --silent --insecure -b .cookie.v8 -XGET -g -i "$MC/v1/configuration/object/ap_group?config_path=/mm&filter=[{\"ap_group.profile-name\":{\"\$eq\":[\"group-ccc\"]}}]&$SID" | grep group
"ap_group": [
"profile-name": "group-ccc",
root@kali:/home/aruba/curl#
>> here is the list unfiltered
root@kali:/home/aruba/curl# curl --silent --insecure -b .cookie.v8 -XGET -g -i "$MC/v1/configuration/object/ap_group?config_path=/mm&$SID" | grep group "ap_group": [
"profile-name": "group-aaa",
"profile-name": "group-bbb",
"profile-name": "group-ccc",
root@kali:/home/aruba/curl#
see if that helps, if not, paste samples of your API calls here