Building or modifying a Gum theme package (Themes/Gum.Themes.*) — restyling Forms controls by subclassing their V3 default visuals. Triggers: any file under Themes/, custom *Visual subclassing Gum.Forms.DefaultVisuals.V3.*, theme entry-point methods like EditorTheme.Apply / DarkProTheme.Apply.
Gum's .gumx schema versioning and migration strategy. Triggers: shape changes to GumProjectSave, ElementSave, or any serialized save class — version bumps, backward-compat shims, XmlSerializer-aware properties that must round-trip across tool versions.
Umbrella for icons in Gum. Triggers: GumIcon, GumIconKind, GumFigmaIconRipper, GumIcons.xaml, FluentIcon usage in the tool, replacing/adding icons in WPF chrome, tree view, or Forms runtime. Read this first before adding an icon anywhere — it routes you to the right pipeline.
Gum Variables tab and DataUiGrid. Triggers: Variables tab, DataUiGrid control, MemberCategory, InstanceMember, category population, property grid refresh, expansion state persistence.
Creates and updates skill files (.claude/skills/*/SKILL.md). Triggers: creating/updating a skill, documenting a subsystem for agent context.
Refactoring direction rules for Gum. Trigger when proposing or performing refactors that change how code is shaped — extracting helpers, choosing between static and instance, deciding where new logic should live. Applies to all Gum source projects.
How Gum.Shapes.MonoGame / Gum.Shapes.KNI ship platform-specific apos-shapes.xnb. Triggers: editing Runtimes/GumShapes/MonoGameGumShapes.csproj, Runtimes/GumShapes/KniGumShapes.csproj, anything under Runtimes/GumShapes/buildTransitive/, or shipping/republishing those packages.
Runtime hot reload — FileSystemWatcher rebuilds the Gum element tree when .gumx/.gusx/.gucx/.gutx/.fnt files change. Triggers: GumHotReloadManager, IGumHotReloadManager, GumService.EnableHotReload, debounce, font cache eviction during reload.