Build tense systemic stealth gameplay in Unity
Give your AI real perception and awareness. Guards see, hear and feel your presence, grow suspicious instead of spotting you instantly, and coordinate searches after you disappear. Hide in shadows, sneak through tall grass, drag bodies out of sight, and outsmart guards that share everything they learn.
Whether you're building a dedicated stealth game or adding stealth to an action title, this system gives you the tools to create tense, emergent gameplay without building the AI from scratch.
Quickstart | Documentation | Videos | Discord
Key Features
Perception that feels believable
- Vision, Hearing & Touch Sensors — Guards detect players naturally instead of relying on simple trigger zones.
- Primary & Peripheral Vision — Separate vision zones with independent shapes, ranges and detection speeds.
- Hearing — Configure sound priorities so gunshots outrank footsteps or thrown objects, with optional NavMesh-based sound propagation that lets walls muffle noise.
- Touch Detection — Bumping into a guard instantly gives you away.
Stealth that rewards smart play
- Light-Based Concealment — Visibility can be calculated from your actual scene lights, allowing players to disappear into shadows.
- Hiding Areas — Hide inside tall grass, boxes, bins, containers and other concealment spots that suppress detection.
- Gradual Detection — Awareness builds over time instead of instantly, then fades as players stay hidden, complete with on-screen detection meters.
- Cover System — Press against walls and crates, with low and high cover detected automatically, to break a guard's line of sight.
Dynamic guard behavior
- Suspicion Factors — Guards react differently depending on where you are and what you're carrying.
- Restricted Areas — Guards warn trespassers with escalating callouts before resorting to force.
- Hostile Areas — Entering dangerous zones triggers immediate combat.
- Weapon Suspicion — Walking around with a drawn weapon can expose you instantly.
- Distraction System — Throw objects or create sounds to lure guards away from their patrols.
- Visual Evidence — Guards investigate dead bodies and other suspicious objects left behind.
Hide the evidence
- Body Carrying — Pick up bodies and move them before they're discovered.
- Body Stashing — Dump bodies into bins, dumpsters, crates or any container you set up.
Coordinated squad AI
- Escalating Situations — Guards transition naturally between Suspicious Investigation, Alerted Investigation and Trespassing Response.
- Smart Coordination — Guards work as a team. When one notices something, nearby guards are alerted. Some go to investigate, and the rest spread out to search hiding spots around the area.
- Procedural Search Behavior — Guards generate search points around the last known position, creating believable area sweeps instead of walking to a single waypoint.
- Contextual Dialogue — Guards respond differently to footsteps, gunshots, trespassing and other events with situation-specific voice lines.
Built for developers
- Data-Driven AI — A visual AI state machine with blackboard-based communication makes it easy to create new behaviors without writing code.
- Built-in Integrations — Works with the Shooter, Melee Combat and Parkour & Climbing systems, enabling stealth takedowns, air assassinations, ledge finishers and more.
- Multiple Demo Scenes — Explore examples covering core stealth, trespassing, body carrying and stashing, and light-based stealth gameplay.
- Built-in Agent Skills — step-by-step instructions for AI coding agents covering setup, character creation and every major workflow.
Modular Integration with other FS Systems - Seamlessly works with other FS Systems like Melee Combat System, Shooter System, Parkour and Climbing System, Inventory System, etc.
Note: The Stealth System is built on top of our character controller and our AI framework. The guards run on our AI state machine, so adding the sensors to your own AI characters means wiring them into your existing behavior logic yourself. On the player side, features like crouch-based hiding, footstep noise, throwing distractions, body carrying and cover all rely on our controller. If you want to use a custom player controller, you'll need to handle that integration yourself.
This asset uses royalty-free sound effects from Pixabay and fonts licensed under the SIL Open Font License (OFL) 1.1. See the Third-Party Notices.txt file in the package for details.
The demo scene includes placeholder dialogue audio generated with Chatterbox, an open-source text-to-speech model developed by Resemble AI and released under the MIT License. See the Third-Party Notices.txt file in the package for details.
