Stealth is a core mechanic of Monaco: What's Yours Is Mine. In Monaco, stealth is the status of being unseen or inconspicuous, though "stealth" can be easily entered and broken. All missions in Monaco (aside from the Player versus Player maps) can be completed with stealthy tactics or (with more difficulty) without them.
Overview[]
There is no persistent indicator to indicate stealth, however the player character will become a black silhouette when they cannot be seen by enemies. In addition, the background music of the level will become fast and excited whenever the player (or players) breaks stealth. Furthermore, most enemies will yell something whenever they detect a player. A ! (exclamation) mark will appear where ever a player is detected and where ever a guard will investigate.
Stealth itself does not provide any benefits other than the fact that the player will not be attacked and cannot be seen in PvP.
Sight detection[]
While in the open, players can be seen by guards or civilians if the players are within the enemies' cone of vision. The cone of vision is invisible to the player, and it extends about 90 degrees from each side of an enemy.
When a player is seen by an enemy, a ? (question mark) icon will begin to appear above any enemy that detects the player. This is the wary stage. As long as the player is standing inside the cone of vision, the mark will "fill up" and eventually become an exclamation mark (!). Once this occurs, the enemy will attack or alert another enemy, unless it is a Helicopter (which does not have a cone of vision and has different mechanics).
It is important to note that an enemy that cannot reach the player or attack them will not become alerted. An enemy in this situation will continue to have a ? over their head, but will not ever have a !.
Enemy behavior[]
When in stealth, enemies will continue navigating their predetermined patrols. Alarms will sound if the player is detected, and the player will not be immediately detected by enemies.
When out of stealth, such as when an enemy responds to an alarm, the player may be immediately detected by alerted enemies and may be attacked. In addition, triggered alarms will reveal the player's location and some electronic traps (such as double locked doors) may trigger.
Entering and exiting stealth[]
At the beginning of a level and whenever a player is not being actively pursued by an enemy, the player is in stealth. A player can be said to exit stealth whenever their position is revealed (i.e. whenever an exclamation mark ! appears near their position), however stealth is not truly broken until an enemy attacks the player.
Tools[]
Some tools that the player can use will immediately break the stealth of any one who uses it by immediately revealing their position. Shotguns, machine guns, C4 and rocket launchers are some examples. Killing an enemy with a wrench will also alert enemies within a short radius.
On the other hand, the Smoke Bomb will hide the player (thus reentering stealth), and a Tranquilizer gun will silently pacify an enemy, akin to the Cleaner's ability. Furthermore, a wrench can silently and instantly disarm an electronic trap or open an alarmed door. Furthermore, disguises will pacify enemies towards players in disguise, even if an enemy was already attacking the player. However, disguises are limited and can only deter guards and civilians; dogs can still track players with disguises (even though they might not attack them) and electronics will detect players in disguise.
Electronics[]
Interactables#Electronics such as cameras and turrets can detect the player and reveal their location to enemies. For instance, using a scan door without a hack will sound an alarm.
Some electronics will indirectly alert enemies, such as the explosion from a placed C4 charge triggered by a camera.
Enemies[]
Enemies can detect players using the cone of vision detection mechanic, or through other means. Dogs can sniff out the player (or players) by following their scent. Helicopters will detect any player that is within their headlights.
Other forms of detection[]
Players can be detected if they run behind enemies instead of sneak behind them. In addition, running causes a thief to become noticed faster.