# State Machine > Implement state machine patterns in Godot for game logic, AI behavior, and player states. Use this skill when creating player state machines (idle/run/jump/attack), enemy AI behaviors (patrol/chase/attack), game state management (menu/playing/paused), or any system that needs clean state transitions. - **Type:** Skill - **Install:** `agentstack add skill-leex852-skills-state-machine` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [LeeX852](https://agentstack.voostack.com/s/leex852) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [LeeX852](https://github.com/LeeX852) - **Source:** https://github.com/LeeX852/skills/tree/main/godot-Developer/skills/godot-dev/state-machine ## Install ```sh agentstack add skill-leex852-skills-state-machine ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # State Machine Pattern ## Base State Machine ```gdscript class_name StateMachine extends Node signal state_changed(old_state: String, new_state: String) @export var initial_state: State var current_state: State var states: Dictionary = {} func _ready(): for child in get_children(): if child is State: states[child.name.to_lower()] = child child.state_machine = self child.player = owner if initial_state: current_state = initial_state current_state.enter() func _process(delta): if current_state: current_state.process(delta) func _physics_process(delta): if current_state: current_state.physics_process(delta) func transition_to(new_state_name: String): var new_state = states.get(new_state_name.to_lower()) if not new_state: push_error("State not found: " + new_state_name) return if current_state: current_state.exit() var old_state_name = current_state.name if current_state else "" current_state = new_state current_state.enter() state_changed.emit(old_state_name, new_state_name) ``` ## Base State Class ```gdscript class_name State extends Node var state_machine: StateMachine var player: CharacterBody3D func enter(): pass func exit(): pass func process(delta: float): pass func physics_process(delta: float): pass ``` ## Player State Machine ### Idle State ```gdscript extends State func enter(): player.velocity = Vector3.ZERO player.animation_player.play("idle") func physics_process(delta: float): var input_dir = Input.get_vector("left", "right", "forward", "back") if input_dir.length() > 0: state_machine.transition_to("Run") return if Input.is_action_just_pressed("jump"): state_machine.transition_to("Jump") return if Input.is_action_just_pressed("attack"): state_machine.transition_to("Attack") return if not player.is_on_floor(): state_machine.transition_to("Fall") ``` ### Run State ```gdscript extends State @export var speed = 5.0 func enter(): player.animation_player.play("run") func physics_process(delta: float): var input_dir = Input.get_vector("left", "right", "forward", "back") var direction = (player.transform.basis * Vector3(input_dir.x, 0, input_dir.y)).normalized() if direction: player.velocity.x = direction.x * speed player.velocity.z = direction.z * speed player.look_at(player.global_position + direction) else: state_machine.transition_to("Idle") return if Input.is_action_just_pressed("jump"): state_machine.transition_to("Jump") return if Input.is_action_just_pressed("attack"): state_machine.transition_to("Attack") return player.move_and_slide() ``` ### Jump State ```gdscript extends State @export var jump_force = 4.5 func enter(): player.velocity.y = jump_force player.animation_player.play("jump") func physics_process(delta: float): player.velocity.y -= ProjectSettings.get_setting("physics/3d/default_gravity") * delta var input_dir = Input.get_vector("left", "right", "forward", "back") var direction = (player.transform.basis * Vector3(input_dir.x, 0, input_dir.y)).normalized() player.velocity.x = direction.x * speed * 0.8 player.velocity.z = direction.z * speed * 0.8 player.move_and_slide() if player.is_on_floor(): state_machine.transition_to("Idle") ``` ### Attack State ```gdscript extends State @export var attack_duration = 0.5 var attack_timer = 0.0 func enter(): attack_timer = attack_duration player.velocity = Vector3.ZERO player.animation_player.play("attack") player.attack_area.monitoring = true func exit(): player.attack_area.monitoring = false func physics_process(delta: float): attack_timer -= delta if attack_timer 0: player.nav_agent.target_position = patrol_points[current_point] func physics_process(delta: float): if player.nav_agent.is_navigation_finished(): current_point = (current_point + 1) % patrol_points.size() player.nav_agent.target_position = patrol_points[current_point] return var next_pos = player.nav_agent.get_next_path_position() var direction = (next_pos - player.global_position).normalized() player.velocity = direction * patrol_speed player.move_and_slide() if player.can_see_player(): state_machine.transition_to("Chase") ``` ### Enemy Chase State ```gdscript extends State @export var chase_speed = 5.0 func enter(): player.animation_player.play("run") func physics_process(delta: float): if not player.can_see_player(): state_machine.transition_to("Patrol") return var target_pos = player.player.global_position player.nav_agent.target_position = target_pos var next_pos = player.nav_agent.get_next_path_position() var direction = (next_pos - player.global_position).normalized() player.velocity = direction * chase_speed player.move_and_slide() if player.global_position.distance_to(target_pos) < 2.0: state_machine.transition_to("Attack") ``` ## Game State Machine ```gdscript extends Node enum GameState { MENU, PLAYING, PAUSED, GAME_OVER } var current_state = GameState.MENU func change_state(new_state: GameState): match current_state: GameState.PLAYING: get_tree().paused = false GameState.PAUSED: get_tree().paused = false current_state = new_state match new_state: GameState.MENU: show_menu() GameState.PLAYING: start_game() GameState.PAUSED: pause_game() GameState.GAME_OVER: show_game_over() func pause_game(): get_tree().paused = true $PauseMenu.show() ``` ## Best Practices 1. **Single responsibility**: Each state handles one behavior 2. **Clean transitions**: Exit/enter logic in proper places 3. **Signal communication**: Decouple state from external systems 4. **Animation integration**: States control animations 5. **Reusability**: Make states generic where possible 6. **Debug visualization**: Show current state in editor ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [LeeX852](https://github.com/LeeX852) - **Source:** [LeeX852/skills](https://github.com/LeeX852/skills) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-leex852-skills-state-machine - Seller: https://agentstack.voostack.com/s/leex852 - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.