Bevy AI navigation

When to use

Load this when an actor must chase, patrol, or wait, and you need to see which Bevy skill owns the next step. Path data and any future nav crate stay on bevy-navigation. Transform integration stays on bevy-character-movement. Line-of-sight sensors stay on bevy-spatial-queries until a solver exists.

ECS shape

• Components: a mode flag can be an enum Component (see bevy-state-machines for the pattern). Goal position can be your own component. No agent, radius, or layer type was opened.
• Resources: a shared patrol table can be a Resource you define. No navigation resource was opened.
• Systems: read the mode and write a desired velocity or waypoint on Update or Fixed. Use .chain() so policy runs before movement. Do not name a Godot-style agent callback.
• Schedule: Fixed / FixedMain when the result feeds the movement step.

Coming from Godot

Godot idea	Bevy idiom
Chase vs patrol	Enum component plus a system. Not a navigation agent
Retarget throttle	Your timer resource or a fixed-step counter. Check the navigation docs before assuming a retarget API.
Crowd / avoidance	Crowd and avoidance belong on bevy-navigation. Check that skill before naming radii.
Bake vs obstacle	Bake and obstacle handling belong on bevy-navigation.
Line of sight	Line of sight belongs on bevy-spatial-queries.

Scope

• No Bevy navigation module was opened, so node-agent versus server, bake, links, and layers have no Bevy names.
• Sensors that need a cast belong with bevy-physics-2d and bevy-physics-3d once you choose a physics solver.
• Formations and stuck recovery are design notes only.

Expert Knowledge Delta

Target: Bevy 0.20+.

Core ECS types: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. See bevy-events-messaging for their APIs. Systems run in parallel unless .chain() orders the ones that conflict.

Who owns state

Piece	Owner	Who may mutate	Schedule
Data on one entity	Component	One system via Query	Update or FixedMain
One value for the whole app	Resource	One system	Startup to insert, then the schedule that reads it
Spawn	Commands	The spawning system	Startup for the initial world; later schedules for runtime spawn
Order that must not race	.chain()	The chained systems only	Same schedule
Plugin boundary	Plugin	build registers systems and resources	Before the app runs

Borrow rule: two systems that both mutably query the same component must be ordered (.chain()) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API.

Decision

If you need	Do this	Do not
Per-entity data	Component + Query	A Godot node script
App-wide config or clock	Resource	Copy the value onto every entity
Stable simulation step	FixedMain and the Fixed clock	Tie simulation to raw frame Update
Startup spawn	Commands in Startup	Spawn from a render system
Cross-system notice that is not shared state	Message or observer slot in bevy-events-messaging	A new event type invented in this file
An API outside the documented set	Check the official docs first	A made-up crate or API

Load references/ecs-ownership.md for the ownership table.

NEVER

• Do not pin /0.20.0/ in docs URLs. WHY: links stay on latest; the 0.20 target is stated once in prose.

• Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless .chain() orders them.

• Do not invent a physics, navigation, networking, or XR crate here. WHY: this skill only names documented Bevy crates and modules.

• No Godot navigation agent or server types. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

• No named third-party navigation or physics crate. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

• No invented path, bake, or avoidance APIs. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

Reference

docs.rs links use the unversioned latest permalink. The library pin on bevy-master stays 0.20.0.

Official Documentation

• Migration guides - Unversioned hop index.
• bevy crate - Unversioned API index. No AI navigation module was opened.
• Assets - Official asset catalog. No AI plugin was selected.
• Examples - Example tree on the latest branch.
• ECS - Component, Resource pairing via bevy-data-resources, systems, and .chain().
• bevy::state - App states are not per-entity patrol modes. Per-entity flags stay components (bevy-state-machines).

Related Skills

Prerequisites

• bevy-master - ECS ownership.
• bevy-navigation - Paths and navigation meshes.
• bevy-state-machines - Enum components for a mode flag.

Complements

• bevy-character-movement - Integrates a waypoint or velocity.
• bevy-spatial-queries - Sensors and spatial queries.
• godot-ai-navigation - Equivalent Godot skill.

Downstream / consumers

• None yet.

Master

• bevy-master - Bevy router.