If you go to Mod in the Menu Screen and select the editor below, you may view existing skills and their functions. As ambergrain has mentioned, Obedience is the main requirement and it must be either 25 or less. It also can't be used on master.
Not particularly sure of what operator "lte" however most likely to be "Less Than or Equal", but do correct me if I'm wrong.
Requirements for Public Execution:
"targetreqs" : [
{"check":false,"code":"is_master"},
{ "code" : "stat",
"stat" : "obedience",
"operant" : "lte",
"value" : 25
}