When doing something on the receiving side in a CPF (Command Propagation Facility) environment, the TSSINSTX exit code only has an entry for CPF (72). All notes for this entry point of CPF refer to Sending side.
The TSSINSTX entry to check inbound commands is the COMMAND entry point.
It is described as follows within TSSINSTX:
TO INTERPRET TSS COMMAND USAGE TXACTGTS CAN BE USED TO DETERMINE THE MACHINE OF ORIGIN WHEN CPF IS IN USE.
TXACTGTS = 0 INDICATES THE COMMAND ORIGINATED ON THE LOCAL MACHINE.
IF TXACTGTS > 0, THEN IT POINTS TO THE 8-CHAR NODE NAME OF THE ORIGINATING MACHINE.
For more information on the COMMAND entry point, see COMMAND—Command Use Validation.