Gum

Gum tool C# code generation. Triggers: CodeGenerator, CodeOutputPlugin, generated code structure, .codsj settings, OutputLibrary selection, Forms codegen, state generation. For CLI/headless codegen see gum-cli.

Where runtime-feature demo screens go. Triggers: adding a sample/demo page for a new runtime feature, NineSliceScreen/SpriteScreen, shape demos, MonoGameGumInCode, Samples/raylib, SilkNetGum.

Forms DefaultVisuals — code-only visual classes backing Forms controls. Triggers: ButtonVisual, any *Visual class in DefaultVisuals/, Styling, DefaultFormsTemplates registration, custom code-only Forms visuals.

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.

Test-first discipline for Gum. Triggers: behavior changes (bug fix or feature) under GumCommon/, Gum/, MonoGameGum/, RenderingLibrary/, KniGum/, FnaGum/, SkiaGum/, RaylibGum/, Tools/Gum.ProjectServices/. Skip for docs, renames, csproj/projitems plumbing, style-only edits.

Unifying per-platform runtime files (MonoGame/Raylib/Skia/KNI/FNA, plus the Apos.Shapes ↔ SkiaGum shape-runtime pair) into one source with

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.

Answering Discord/GitHub user questions — search skills→docs→code, cite the docs URL, suggest doc/API fixes with confidence, or file an issue. Triggers: pasted user question, "how do I", GitHub issue triage, "answer this person".

Gum's MonoGame rendering pipeline — Renderer/SpriteBatchStack/GumBatch, BatchKey transitions, SpriteBatch ↔ Apos.Shapes ShapeBatch interleaving. Triggers: Renderer.cs, SpriteBatchStack.cs, GumBatch, RenderableShapeBase, SpriteBatchRenderableBase, BatchKey, draw-order bugs, GumRenderBatch in FRB2/MonoGameGumImmediateMode.

Gum undo/redo. Triggers: History tab, UndoManager, UndoPlugin, UndoSnapshot, stale references after undo.

Conventions for filing GitHub issues in the Gum repo via gh. Triggers when the user asks to "log an issue", "create an issue", "file a bug", or otherwise capture a problem/idea as a GitHub issue (as opposed to fixing one).

Gum's behaviors system and the design-time → runtime Forms wrapping lifecycle. Triggers: BehaviorSave, ElementBehaviorReference, StandardFormsBehaviorNames, FormsUtilities.RegisterFromFileFormRuntimeDefaults, DefaultFromFile*Runtime classes, Forms properties not settable at design time.

Gum dialog/popup systems. Triggers: DialogService, DialogWindow, DeleteOptionsWindow, dialog scrolling/layout, adding new dialog types, ShowMessage/ShowYesNoMessage, mocking IDialogService in unit tests.

Creates and updates skill files (.claude/skills/*/SKILL.md). Triggers: creating/updating a skill, documenting a subsystem for agent context.

Forms controls (FrameworkElement subclasses). Triggers: Button, CheckBox, ListBox, ComboBox, TextBox, ScrollViewer, anything in Gum.Forms.Controls or FlatRedBall.Forms.Controls, FrameworkElement itself, the Visual/InteractiveGue relationship, state machines, DefaultVisuals, ReactToVisualChanged.

Gum tool plugin system, including visualization plugins (EditorTabPlugin_XNA, TextureCoordinateSelectionPlugin). Triggers: plugin registration, PluginBase, PriorityPlugin, PluginManager, plugin events, finding which internal plugin owns a feature.

Writing unit tests in the Gum repo. Triggers: tests in Gum.ProjectServices.Tests, Gum.Cli.Tests, or any other Gum test project.

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.

Writing Gum docs in GitBook markdown. Triggers: editing docs/, SUMMARY.md, GitBook hints/figures, cross-page links, doc images.

The "Import from .gumx" dialog. Triggers: ImportFromGumxPlugin, GumxDependencyResolver, ImportTreeNodeViewModel, ImportFromGumxView, importing components/screens/behaviors/standards across projects, the dialog's TreeView templating.

Gum tool ViewModel conventions. Triggers: ViewModels, XAML views, data binding, DependsOn, visibility properties.

GumService — runtime entry point for MonoGame/Raylib/KNI/FNA. Triggers: GumService init, Uninitialize, DeferredQueue, hot reload, Root/PopupRoot/ModalRoot containers.

Drafts the end-of-month Gum release notes from PRs and commits since the last release. Outputs a draft in /temp/ in the hybrid format — curated Breaking Changes / Biggest Changes / Gum Tool / Gum Runtimes / Tutorials and Templates highlights on top, then a complete per-PR "What's Changed" list, then the Full Changelog placeholder — with image placeholders. User-triggered near month end.

Gum Variables tab and DataUiGrid. Triggers: Variables tab, DataUiGrid control, MemberCategory, InstanceMember, category population, property grid refresh, expansion state persistence.

How Gum instantiates runtime objects from save data and applies variables to renderables. Triggers: ToGraphicalUiElement, SetGraphicalUiElement, ApplyState, SetProperty, SetVariablesRecursively, CustomSetPropertyOnRenderable, font loading, IsAllLayoutSuspended, isFontDirty.

Gum variable references — Excel-like cross-instance/cross-element binding via Roslyn-parsed assignments. Triggers: VariableReferenceLogic, EvaluatedSyntax, ApplyVariableReferences, VariableChangedThroughReference, VariableReferences VariableListSave.

Map of Gum's render-backend projects and every place that compiles shared Gum source. Triggers: moving/renaming/deleting runtime or GumCommon/RenderingLibrary files, AllLibraries.sln, SkiaGum.Wpf, FRB GumCoreShared/Forms shproj, duplicate same-FQN build errors, "what must I rebuild after a runtime refactor."

Runtime variable reference propagation and the optional Gum.Expressions NuGet. Triggers: ApplyAllVariableReferences, GumExpressionService, runtime styling/theming, GumExpressions project.

How the Gum tool authors state-based animations — StateAnimationPlugin, Animations tab, .ganx sidecars. Triggers: Animations tab, StateAnimationPlugin, ElementAnimationsSave, AnimationSave, AnimatedStateSave, .ganx, named events.

Verify FlatRedBall (FRB1) still compiles after editing Gum source it shares. Triggers: changes under GumCommon/ or MonoGameGum/Forms/, projitems sync, the FRB compile constant, CS0246/CS0103 from FRB. Only when a FlatRedBall checkout sits beside the Gum repo.

The integer version stamped on Gum runtime assemblies via GumSyntaxVersionAttribute, used by the tool's codegen to gate emitted code. Triggers when bumping the runtime syntax version, touching AssemblyAttributes.cs in GumCommon/MonoGameGum/RaylibGum/SkiaGum, or changing SyntaxVersionDetectionService.

Gum runtime cursor-event dispatch — how Click/Push/RollOver/etc. are raised and routed. Triggers: InteractiveGue, DoUiActivityRecursively, RoutedEventArgs, HandledActions, ClickPreview, RollOverBubbling, ClickBubbling, HasEvents, ExposeChildrenEvents, adding/bubbling a visual event.

Gum release/build orchestration — drives the in-repo release checklist and hands off the notes draft. Triggers: cutting a release, publishing the Gum NuGet packages, releasing the tool, /gum-release.

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.

Deep internals of Gum's layout engine — UpdateLayout call chain, UpdateChildren ordering, stacking pipeline, dirty state, perf. Triggers: debugging/optimizing UpdateLayout/UpdateChildren, RefreshParentRowColumnDimensionForThis, GetWhatToStackAfter, MakeDirty, ResumeLayoutUpdateIfDirtyRecursive, _cachedSiblingIndex.

Gum delete architecture. Triggers: delete commands, IEditCommands delete methods, IDeleteLogic, DeleteLogic, DeleteOptionsWindow, HandleDeleteCommand, AskToDeleteState, AskToDeleteStateCategory, DeleteSelection.

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.

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.

GumCli — headless CLI for Gum projects. Triggers: gumcli commands (new, check, diff-standards, codegen, codegen-init, fonts, screenshot, svg), Gum.ProjectServices, HeadlessErrorChecker, ProjectLoader, HeadlessCodeGenerationService, CodeGenerationAutoSetupService, FormsTemplateCreator, DiffStandardsService.

Gum copy/paste. Triggers: CopyPasteLogic, ICopyPasteLogic, OnCopy/OnPaste/OnCut, PasteInstanceSaves, CopiedData, clipboard behavior, multi-paste selection tracking.