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Coming with the next Summer Engine update. Nothing on this page works yet: editor docks, apps that read or write your game files, the summer.engine.* calls, summer_app_dock and paired plugins all need that release. Until then, keep an app’s data in Summer with summer.data collections.

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How an app reaches your engine

  • Inside Summer Engine (the Studio tab or a dock), engine calls go straight to your open project.
  • In a browser, they reach your running Summer Engine through Summer when the desktop app is online and signed in. If no engine is connected, the call fails with engine_offline; show “Open in Summer Engine”.
  • If more than one Summer Engine is open, a call fails with engine_target_ambiguous until one is picked: summer.engine.targets() lists them and summer.engine.useTarget(instanceId) picks one. Studio also asks the person “Which Summer Engine?”.
  • If only a Summer Engine too old for apps is open, a call fails with engine_update_required.
An app needs engine:read or engine:write in its manifest. It may read and write only the files it declares in engineFiles, plus res://addons/<plugin>/ when it declares a plugin. summer.engine.onEvent and summer.engine.plugin.* work only inside Summer Engine.

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What an app may do

Allowed operations (summer.engine.ops, 1 to 50 per call): Values are Godot strings, not JSON objects: "position": "Vector3(0, 10, 0)", "light_color": "#fffef0". Scene changes edit scenePath (a res:// .tscn or .scn file; default: the scene open in the editor). More rules:
  • SaveScene saves only .tscn and .scn files.
  • Imports write asset files outside res://addons/, unless the path is declared.
  • Scene changes may not carry script source.
Never allowed from an app: running scripts, editor scripts or shell commands; deleting, moving or renaming files; writing or reading files outside the declared paths; project settings; extracting zip files; editor-window screenshots. Summer enforces these rules, and the engine enforces them again.

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Docks

An app can dock as an editor panel (left, right or bottom). Docks stay in your editor layout per project. Ask your agent. It uses summer_app_dock from the summer-engine npm package:
slot is left, right (default) or bottom. summer_app_dock also closes a dock ("action": "close") and lists docks ("action": "list"). On engine builds without app docks it answers engine_lacks_op; open the app in the Studio tab instead. On the app page, Dock in editor does the same in the desktop app.

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Plugins

An agent can build an editor plugin (res://addons/<name>/) together with an app. Declare it as "plugin": { "name": "<name>" } in the manifest. The app and the plugin message each other through the engine: summer.engine.plugin.send(message) and summer.engine.plugin.onMessage(fn) in the app. The npm package’s summer_enable_plugin turns the plugin on in the open project and reports the result.