Are RFCOMM packets guarnteed to be whole?

Question

I'm writing an application that interfaces with Bluetooth devices using Headset Profile. These devices primarily communicate via AT commands send over a Serial Port Profile (SPP) connection. SPP is directly on top of RFCOMM.

My concern is whether or not I am guaranteed to receive "whole" packets (AT commands), or if there is a possibility that I will need to be able to handle an AT command split across multiple packets.

Furthermore, if the RFCOMM protocol does not guarantee this, does the protocol stack do any processing to guarantee receiving "whole" AT commands? I am using BlueZ 5.46 on a Linux 4.12 kernel.

If possible, please reference the standard or an external source that details how RFCOMM guarantees this so I can learn a bit more about it.