Unity UI Toolkit Skills

Use this module for Unity UI Toolkit only: UXML for structure, USS for styling, UIDocument for scene attachment, and PanelSettings for runtime rendering.

Requires Unity 2022.3+. Do not mix this module with ui_* UGUI/Canvas skills. Localization: Match visible UI text to the user's language. Chinese conversation -> Chinese labels/placeholders/button text. USS class names and CSS variables stay English.

Guardrails

Mode: Full-Auto required

DO NOT (common hallucinations):

• uitoolkit_create_button / uitoolkit_create_label do not exist -> use uitk_add_element
• uitoolkit_set_style does not exist -> use uitk_add_uss_rule, uitk_remove_uss_rule, or uitk_modify_element
• uitoolkit_create_canvas does not exist -> UI Toolkit uses UIDocument, not Canvas
• uitk_* and ui_* are different systems. Do not mix UI Toolkit structure/styling assumptions into UGUI workflows
• USS is not full CSS. display:grid, box-shadow, calc(), @media, ::before, z-index, and gradients are unsupported

Routing:

• For UGUI Canvas/Button/Text/Image -> use the ui module
• For XR world-space Canvas conversion -> use xr_setup_ui_canvas
• For generated starter layouts -> use uitk_create_from_template
• For attaching an existing UXML to a scene object -> use uitk_create_document or uitk_set_document

Skills

File Skills

Skill	Use	Key parameters
uitk_create_uss	Create USS file	savePath, content?
uitk_create_uxml	Create UXML file	savePath, content?, ussPath?
uitk_read_file	Read USS/UXML content	filePath
uitk_write_file	Overwrite file content	filePath, content
uitk_delete_file	Delete USS/UXML file	filePath
uitk_find_files	Search files by name/path	type?, folder?, filter?, limit?
uitk_create_batch	Create 2+ files in one call	items

Scene Skills

Skill	Use	Key parameters
uitk_create_document	Create UIDocument GameObject	name, uxmlPath?, panelSettingsPath?, sortOrder?, parentName?/parentInstanceId?/parentPath?
uitk_set_document	Change UIDocument asset bindings	name/instanceId, uxmlPath?, panelSettingsPath?
uitk_create_panel_settings	Create PanelSettings asset	savePath, scaleMode, referenceResolutionX/Y, Unity 6 world-space options
uitk_get_panel_settings	Read PanelSettings values	assetPath
uitk_set_panel_settings	Update PanelSettings selectively	assetPath, changed fields only
uitk_list_documents	List scene UIDocuments	none
uitk_inspect_document	Inspect live VisualElement tree	name/instanceId/path, depth

UXML Structure Skills

Skill	Use	Key parameters
uitk_add_element	Add a child element	filePath, elementType, parentName?, elementName?, text?, classes?
uitk_remove_element	Remove by name	filePath, elementName
uitk_modify_element	Change attributes/classes/text	filePath, elementName, text?, classes?, style?, newName?, bindingPath?, custom attribute fields
uitk_clone_element	Duplicate an element subtree	filePath, elementName, newName?
uitk_inspect_uxml	Parse UXML hierarchy	filePath, depth?

USS Style Skills

Skill	Use	Key parameters
uitk_add_uss_rule	Add or replace selector rule	filePath, selector, properties
uitk_remove_uss_rule	Remove selector rule	filePath, selector
uitk_list_uss_variables	Inspect design tokens / var() usage	filePath

Template and CodeGen Skills

Skill	Use	Key parameters
uitk_create_from_template	Generate paired UXML+USS	template, savePath, name?
uitk_create_editor_window	Generate EditorWindow script	savePath, className, uxmlPath?, ussPath?, menuPath?
uitk_create_runtime_ui	Generate runtime MonoBehaviour query scaffold	savePath, className, elementQueries?

Supported starter templates include menu, hud, dialog, settings, inventory, list, tab-view, toolbar, card, and notification.

Core Domain Knowledge

USS vs CSS

Pattern	Supported in USS	What to do
Flex layout	Yes	Use flex-direction, flex-wrap, align-items, justify-content
border-radius, opacity, overflow:hidden	Yes	Safe to use
Transforms / transitions	Yes	translate, scale, rotate work
CSS variables	Yes	Prefer :root tokens
display:grid / display:block / display:inline	No	Everything is flex; emulate grids with wrapping rows
box-shadow	No	Fake with nested background element
linear-gradient() / radial-gradient()	No	Use image textures
calc() / @media	No	Use explicit values + PanelSettings.scaleMode
::before / ::after	No	Add a real child VisualElement
z-index	No	Later siblings render on top

Common USS workarounds

Need	USS-safe workaround
Shadow	Extra child VisualElement behind content
Responsive scaling	PanelSettings.scaleMode = ScaleWithScreenSize
Grid cards	flex-direction: row + flex-wrap: wrap + child widths
Circular avatar	Equal width/height + radius = half size + overflow:hidden
Pseudo decoration	Add an extra absolutely positioned child

High-Frequency Parameters

Skill	Parameters you usually need first
uitk_create_panel_settings	savePath, scaleMode, referenceResolutionX, referenceResolutionY
uitk_create_document	name, uxmlPath, panelSettingsPath, sortOrder?
uitk_add_element	filePath, elementType, parentName?, elementName?, text?, classes?
uitk_modify_element	filePath, elementName, changed attributes only
uitk_add_uss_rule	filePath, selector, properties

PanelSettings choices

• ScaleWithScreenSize: default for runtime HUD/menu UI
• ConstantPixelSize: use when strict pixel mapping matters
• ConstantPhysicalSize: rare; only for physically sized UI requirements

Unity 6 world-space flows also need the scene-side document camera setup after configuring PanelSettings.

File and Structure Rules

• Prefer one UXML root that references shared token/style files through <Style src="..."/>.
• Keep USS next to UXML when possible so relative style references stay short.
• Use uitk_inspect_uxml before complex structural edits if you did not create the file yourself.
• uitk_create_uxml can auto-reference a stylesheet when ussPath is provided.

Workflow Notes

1. Create USS/UXML first, then attach them through uitk_create_document.
2. Runtime rendering needs a valid PanelSettings asset.
3. When USS and UXML are in the same folder, prefer <Style src="MyStyle.uss" />; use a full asset path only for cross-folder references.
4. Start with design tokens, then component rules, then layout containers.
5. For incremental edits, prefer uitk_read_file -> edit -> uitk_write_file.
6. When creating 2+ files, use uitk_create_batch.
7. Unity 6 world-space rendering uses PanelSettings world-space options plus the scene-side UIDocument camera setup.
8. Use uitk_create_from_template when the user needs a starter screen fast; use uitk_add_element / uitk_add_uss_rule for targeted edits on existing files.

Minimal Example

import unity_skills

unity_skills.call_skill("uitk_create_panel_settings",
    savePath="Assets/UI/GamePanel.asset",
    scaleMode="ScaleWithScreenSize",
    referenceResolutionX=1920,
    referenceResolutionY=1080
)

unity_skills.call_skill("uitk_create_uss",
    savePath="Assets/UI/HUD.uss",
    content=":root { --accent: #E8632B; } .title { color: var(--accent); }"
)

unity_skills.call_skill("uitk_create_uxml",
    savePath="Assets/UI/HUD.uxml",
    content="<?xml version=\"1.0\" encoding=\"utf-8\"?><engine:UXML xmlns:engine=\"UnityEngine.UIElements\"><Style src=\"HUD.uss\" /><engine:Label class=\"title\" text=\"Start\" /></engine:UXML>"
)

unity_skills.call_skill("uitk_create_document",
    name="HUD",
    uxmlPath="Assets/UI/HUD.uxml",
    panelSettingsPath="Assets/UI/GamePanel.asset"
)

Exact Signatures

Exact names, parameters, defaults, and returns are defined by GET /skills/schema or unity_skills.get_skill_schema(), not by this file. Load USS_REFERENCE.md before generating non-trivial USS systems, layout patterns, component styles, or complete examples.