A full .guitkx editor inside the Godot editor — the authoring companion for the "Reactive UI (React for Godot)" addon. Double-click a .guitkx in the FileSystem dock and edit it in a main-screen tab: theme-matched syntax highlighting (embedded GDScript included), live compiler diagnostics with gutter icons and a project-wide Problems panel, completion for tags/attributes/values/directives/hooks/events, hover docs, signal-aware signature help, Ctrl+Click go-to-definition, find references, project-wide rename, find/replace and project search, outline, bookmarks, multi-file sessions with full state restore, and the same formatter as the VS Code extension (guitkx.config.json honored, format-on-save available). Saving plays cleanly with the runtime watcher and Fast Refresh: save while the game runs and the live UI hot-reloads with hook state preserved.

Requires the "Reactive UI (React for Godot)" addon, 0.8.4 or newer: enable reactive_ui first, then reactive_ui_editor (Project Settings -> Plugins).

The download bundles the reactive_ui_analyzer GDExtension (Windows x86_64, Linux x86_64/arm64, macOS universal) — embedded GDScript inside expressions and setup code gets type-aware completion, hover, diagnostics, navigation, rename, and signature help out of the box, no extra install. Editor-only tooling: exclude addons/reactive_ui_analyzer from game export presets. macOS: the bundled library is unsigned — its README has the one-line fix. Developed with AI assistance (Anthropic's Claude) under human direction.