Fallout 4: Sneak

Perk Strategies & How Best to Use Them

Fallout 4's Sneak Perk allows you to use stealth effectively, but is best coupled with Agility. Taking at least the fourth rank is recommended if you want to play a sniper/assassin or melee sneak build. Here are the five ranks of the perk, its level requirements, and Perk IDs for people who'd like to cheat:

Gameplay Effects & Utility
The first point of the Sneak Perk gives more than the others, but as I explain in my Stealth guide, this multiplies the benefit you get from agility. The game seems to take your agility into account, then multiply it with this and covert ops manuals to determine how good your character is at sneaking. This, coupled with light, weight of clothing, line of sight, and enemy perception. So, characters with higher Agility will benefit more from this than those without it, but taking just one point will certainly make low perception enemies have a harder time detecting a character with lower agility. The gains from Agility are small (as is typical of SPECIAL bonuses), but this can multiply their impact, and with the help of darkness allow you to walk behind opponents. Actually, it's amazing how well hidden you can be even without armor suited to stealth - I've had feral ghouls walk directly in front of my character without being noticed (they have a Perception of only 4).

At rank 4, you get a new benefit but it's important to make the distinction between running and sprinting. Most of us are probably running at all times, but slowing down (caps lock on PC) will greatly reduce the noise you make while moving. When you take rank 4, you can move at normal speed without affecting stealth at all.

Rank 5 is useful for when you need to escape combat to heal up, as you may in Survival difficulty. You may sprint away, then using your stealth will drop the meter back to where enemies' interest in you is reduced. Of course, it'll also help if you make a mistake and aggro a huge group and need to re-establish 'Hidden' so that you can perform sneak attacks. The AI can be rather dumb when it comes to snipers.

The side benefits of this perk are helpful at times when exploring raider and gunner-infested locations where traps have been set, and will save you from needing to disengage your stealth to run from mines (which you can shoot with a silenced weapon without this perk).

Overall if you desire a stealthy character, you will want at least the first 4 ranks (since the last doesn't improve detection) unless you are going to trick out your armor to aid in stealth (low weight and better in darkness) and track down all the covert ops manuals in the game. With all those things combined, you'll be almost undetectable.