// the find
limbonaut/limboai
LimboAI - Behavior Trees and State Machines for Godot 4
A C++ plugin for Godot 4 that gives you behavior trees and hierarchical state machines, with a visual editor and runtime debugger built into the Godot UI. Aimed at anyone building game AI beyond a basic state-machine-in-GDScript, from solo devs prototyping enemy behavior to small studios shipping something with real combat AI.
Combining BT and HSM in one plugin is rare — most alternatives give you one or the other, and here you can nest a behavior tree inside a state (BTState) instead of picking a paradigm and living with it. It ships as a GDExtension, so you don't need a custom engine build, and you can switch between GDExtension and compiled-module without changing your project. It actually has unit tests for the BT tasks and HSM, which most Godot addons at this scope skip entirely. The visual debugger for inspecting a running tree in-scene is a real feature, not a toy — that's usually the first thing you build by hand when debugging AI.
The version compatibility table is a real cost: plugin version is pinned to specific Godot versions (1.8.x needs 4.6+, older plugin versions for older engines), so upgrading Godot can force a plugin upgrade or vice versa. HSM setup has no GUI editor and requires writing code to wire up states and transitions — only the BT side gets the editor treatment. It's core C++, so if you need to extend internals rather than write GDScript tasks, you're building from source with SCons and managing export templates yourself. It also reads as a single-maintainer project (ko-fi donations, one name on the Mastodon/Discord presence), so bus-factor and long-term maintenance pace are worth watching before betting a shipping game on it.