State Machines in Godot 4.3+

State Machines in Godot 4.3+

Choose the right FSM pattern for your complexity level. All examples target Godot 4.3+ with no deprecated APIs.

Related skills: player-controller for movement state integration, ai-navigation for AI state patterns, resource-pattern for resource-based state configuration, animation-system for AnimationTree states driven by FSM, dialogue-system for dialogue flow as a state machine, ability-system for caster state gating (casting/stunned), limboai for the LimboAI addon's HSM (BTState) if you need a behavior tree alongside your FSM, beehave for a GDScript-only BT alternative.

When to reach for an addon: This skill covers the built-in FSM patterns (enum, node-based, resource-based). If your agent needs a full behavior tree, see limboai (C++ + HSM, Godot 4.6+) or beehave (pure GDScript, Godot 4.1+) instead.

1. Approach Comparison

When you recommend one, name the approach you rejected and the factor that decided it (state count, independent concerns, designer editing) — "node-based, not an enum with match, because seven states with their own enter/exit logic outgrow one script". A pick with no named alternative cannot be overruled.

2. Approach 1: Enum-Based (Simplest)

Use when you have a small number of states and no significant enter/exit logic.

GDScript

extends CharacterBody2D

enum State { IDLE, PATROL, CHASE, ATTACK }

@export var patrol_range: float = 200.0
@export var chase_range: float = 300.0
@export var attack_range: float = 50.0
@export var speed: float = 80.0

var current_state: State = State.IDLE
var patrol_target: Vector2 = Vector2.ZERO