If it's pirates with no backer we can make some (un)educated guesses.
The top pirate JumpShip available on the normal TROs is a
Star Lord. However those are exceedingly rare and only the very best pirate groups have one. As they're by far more common, they probably come in an
Invader or
Merchant, hence two or three Dropships.
They'll want at least one cargo carrier for hauling off loot, as pirates don't generally raid for the lulz. So probably two combat DropShips.
Pirates generally don't have top-end gear. We can discount the possibility of a
Vengeance or
Excalibur as exceedingly remote for the same reason we discount a
Star Lord. Most likely scenario is
Leopards or
Unions, with a chance of a bigger ship like a
Triumph or
Overlord.
With those assumptions, I'd say the most likely scenario is around a 'mech Company of pirates backed by a vehicle company and a couple companies of infantry to go in and steal stuff.
Worse case scenario for pirates is a
Star Lord loaded with five
Triumphs and the pirates just assuming that the 2,000 tons of cargo on each
Triumph will cover whatever they steal, 10,000 tons is not a bad haul. In that case, up to five battalions of mixed vehicles and 'mechs. The middle estimate is going to see the pirates crushed while the worst case scenario is more likely if ComStar is backing them and that's going to be a rough fight for Weber's Warriors.
If ComStar launches an attack on their own, they may duplicate their tactics during the
Tirpitz Affair which is in the same time frame and a similar effort to squash somebody from discovering lostech. They sent a Division, 216 fighters, all Star League advanced tech so that's a reasonable first guess as to their forces. Given that this target is on the ground instead of in orbit, they may send a second ground division of 'mechs to mop up.