Fifth Frontier War had a potentially useful mechanism in case you want to consider it, a
Leadership Rating. Essentially, the leaders have to have orders written for them in advance equal to their rating. So a rating 4 leader will have 4 turns of orders written for them, so if you write orders for them on turn 3, they will get to them on turn 7 (when those orders might be out of date). Leaders with a rating 0 are extremely rare.
Could something like this be used for spies in enemy territory? You send a spy in and write what orders you want them to do, and when they get to those orders they execute them. Depending on conditions, you might be able to have the spies order around your units.
For example, you might have a Rating 4 spy perform the following orders (and have to issue them all on turn 4):
Turn: Action
5: Establish network
6: Determine local defenses
7: Transmit Go/No-go to 5th Regiment via pre-arranged code
8: Engage in defensive sabotage to allow for easier landing
On Turn 5, you would write down the order for the spy to execute on turn 9., on turn 6 you would write the order for turn 10, aso.
For the 5th Regiment leader you might have to issue the following orders:
5: Train troops
6: Train troops for specific environment at target planet
7: Await Go/No-go order
8: If Go, attack planet, else Train
However, a pirate raid happens on turn 6, damaging several units in the 5th Regiment making it impossible for them to attack successfully. Unless you can get a quick message to the spy on the target planet, the spy will send the message on turn 7, and begin sabotage operations on turn 8. This sabotage without an invasion means the defender can run counter-intel ops without worrying about countering enemy firepower.
The other fun is if you have a better spy there (1-2 turns of orders), and the opponent manages to capture/kill them, that is a very serious loss.