I have a bunch of custom effects and want to only allow programmatic access to add one of them. Our AEGP will do the programmatic adding. It seemed that returning an error from the PF_Cmd_SEQUENCE_SETUP command handler in the effect we don't want to be addable would do the trick but it doesn't seem to. Any ideas? Thanks.
the most elegant solution would be to set the PF_OutFlag_I_AM_OBSOLETE flag.
it would make the plug-in not appear in the effects menu, yet it will still be available for your AEGP to apply.
the user could still copy/paste the effect against your will, but he/she will not be able to apply a new instance.
even if that doesn't solve the entire problem i'm guessing you'll still want to implement that.