Behavior3 Editor

VS Code behavior tree visual editor for game AI workflows.

Related Projects

• behavior3-ts - TypeScript Runtime Library
• behavior3lua - Lua Runtime

Editor Preview

The editor provides an intuitive visual interface for designing and managing behavior trees. See the screenshot above for the full editing experience with node canvas, inspector panel, and tree organization.

Features

• Visual canvas editor (drag, connect, organize nodes)
• Built-in inspector panel for node/tree properties
• Custom node definitions via .b3-setting
• One-click build command in editor title bar
• Optional expression validation for node args
• Auto theme adaptation (dark/light)

Quick Start

Open a tree file

• Right-click a tree .json file in Explorer
• Select Open With → Behavior3 Editor

Create a new project

• Right-click a folder in Explorer
• Run Behavior Tree: Create Project

Configure nodes

Create a .b3-setting file in workspace:

{
  "nodes": [
    {
      "name": "MyAction",
      "type": "Action",
      "desc": "Does something useful",
      "args": [{ "name": "duration", "type": "float", "desc": "Duration in seconds" }]
    }
  ]
}

Build

Click Build in the editor title bar.

Build Script (.b3-workspace)

settings.buildScript supports ESM scripts:

• JavaScript: .js, .mjs
• TypeScript: .ts, .mts (runtime transpile, no type-check)

Example:

{
  "settings": {
    "checkExpr": true,
    "buildScript": "scripts/build.ts"
  }
}

All build hooks receive env:

• env.fs: Node fs
• env.path: full path helper object (all methods exposed)
• env.workdir: resolved workspace directory
• env.nodeDefs: loaded node definitions map
• env.logger: log/debug/info/warn/error

Use a Hook class. The extension constructs it once with env, then calls methods:

• constructor(env)
• onProcessTree(tree, path, errors)
• onProcessNode(node, errors)
• onWriteFile(path, tree)
• onComplete(status)

For compatibility:

• .ts / .mts: must export a class via named Hook or default
• .js / .mjs: support class export and legacy function-style exports

For TypeScript authoring hints, see:

• sample/scripts/build-script.d.ts
• sample/scripts/build.ts

Extension Settings

Inspector

Inspector is embedded on the right side of the tree editor.

• Select a node to edit node fields (args, input, output, desc, debug, disabled)
• Click empty canvas to edit tree fields (name, desc, vars, import, group)

Keyboard Shortcuts

Development

• Output logs: View → Output → channel Behavior3
• Webview logs are also available in DevTools

Requirements

• VS Code 1.85.0+

License

MIT