A network device for a mobile carrier network sends, to a third-party platform, a first client message including a first parameter extension. The first parameter extension indicates subscription parameters for a data flow between a user equipment (UE) device that originated the first client message and the third-party platform. The network device receives, from the third-party platform, a server message. The server message does not include a confirmation that the third-party platform accepts subscription parameters. The network device forwards, to the UE device, the server message with the first parameter extension. The network device receives, from the UE device, a second client message including a second parameter extension. The second parameter extension confirms that the third-party platform accepts the one or more subscription parameters. The network device then generates a policy enforcement rule for the data flow that relies on the confirmation from the third-party platform.