Could someone tell me what the modules actually do like the stealth field and such I want to get these but are they worthwhile, also codsworth wont hack terminals with hacking mod do hands affect it because he has 2 stealth blades and wont hack I really want a a stealthy bot so tips are welcome

If it is boosting allies stealth and so on, then it would be boosting the player's stealth and so on, but I doubt it makes the robot any more able to hide, regen, and so on.

From my own experience, I believe those robot add-ons just give you a stat increase while that 'bot is a companion- like a piece of legendary armor would give you a +1 or +2 or whatever in whatever perk it specializes in.

Doesn't give the 'bot itself any extra abilities, just bumps up your stats.