Claude Code subagent imported from fcodearts/AmanecerRojoUE (.claude/agents/ue-umg-specialist.md). Copyright stays with the author.

Agent Test Spec: ue-umg-specialist

Agent Summary

• Domain: UMG widget hierarchy design, data binding patterns, CommonUI input routing and action tags, widget styling (WidgetStyle assets), UI optimization (widget pooling, ListView, invalidation)
• Does NOT own: UX flow and screen navigation design (ux-designer), gameplay logic (gameplay-programmer), backend data sources (game code), server communication
• Model tier: Sonnet
• Gate IDs: None; defers UX flow decisions to ux-designer

Static Assertions (Structural)

• description: field is present and domain-specific (references UMG, widget hierarchy, CommonUI)
• allowed-tools: list matches the agent's role (Read/Write for UI assets and Blueprint files; no server or gameplay source tools)
• Model tier is Sonnet (default for specialists)
• Agent definition does not claim authority over UX flow, navigation architecture, or gameplay data logic

Test Cases

Case 1: In-domain request — inventory widget with data binding

Input: "Create an inventory widget that shows a grid of item slots. Each slot should display item icon, quantity, and rarity color. It needs to update when the inventory changes." Expected behavior:

• Produces a UMG widget structure: a parent WBP_Inventory containing a UniformGridPanel or TileView, with a child WBP_InventorySlot widget per item
• Describes data binding approach: either Event Dispatchers on an Inventory Component triggering a refresh, or a ListView with a UObject item data class implementing IUserObjectListEntry
• Specifies how rarity color is driven: a WidgetStyle asset or a data table lookup, not hardcoded color values
• Output includes the widget hierarchy, binding pattern, and the refresh trigger mechanism

Case 2: Out-of-domain request — UX flow design

Input: "Design the full navigation flow for our inventory system — how the player opens it, transitions to character stats, and exits to the pause menu." Expected behavior:

• Does not produce a navigation flow or screen transition architecture
• States clearly: "Navigation flow and screen transition design is owned by ux-designer; I can implement the UMG widget structure once the flow is defined"
• Does not make UX decisions (back button behavior, transition animations, modal vs. fullscreen) without a UX spec

Case 3: Domain boundary — CommonUI input action mismatch

Input: "Our inventory widget isn't responding to the controller Back button. We're using CommonUI." Expected behavior:

• Identifies the likely cause: the widget's Back input action tag does not match the project's registered CommonUI InputAction data asset
• Explains the CommonUI input routing model: widgets declare input actions via CommonUI_InputAction tags; the CommonActivatableWidget handles routing
• Provides the fix: verify that the widget's Back action tag matches the registered tag in the project's CommonUI input action data table
• Distinguishes this from a hardware input binding issue (which would be Enhanced Input territory)

Case 4: Widget performance issue — many widget instances per frame

Input: "Our leaderboard widget creates 500 individual WBP_LeaderboardRow instances at once. The game hitches for 300ms when opening the leaderboard." Expected behavior:

• Identifies the root cause: 500 widget instantiations in a single frame causes a construction hitch
• Recommends switching to ListView or TileView with virtualization — only visible rows are constructed
• Explains the IUserObjectListEntry interface requirement for ListView data objects
• If ListView is not appropriate, recommends pooling: pre-instantiate a fixed number of rows and recycle them with new data
• Output is a concrete recommendation with the specific UMG component to use, not a vague "optimize it"

Case 5: Context pass — CommonUI setup already configured

Input context: Project uses CommonUI with the following registered InputAction tags: UI.Action.Confirm, UI.Action.Back, UI.Action.Pause, UI.Action.Secondary. Input: "Add a 'Sort Inventory' button to the inventory widget that works with CommonUI." Expected behavior:

• Uses UI.Action.Secondary (or recommends registering a new tag like UI.Action.Sort if Secondary is already allocated)
• Does NOT invent a new InputAction tag without noting that it must be registered in the CommonUI data table
• Does NOT use a non-CommonUI input binding approach (e.g., raw key press in Event Graph) when CommonUI is the established pattern
• References the provided tag list explicitly in the recommendation

Protocol Compliance

• Stays within declared domain (UMG structure, data binding, CommonUI, widget performance)
• Redirects UX flow and navigation design requests to ux-designer
• Returns structured findings (widget hierarchy + binding pattern) rather than freeform opinions
• Uses existing CommonUI InputAction tags from context; does not invent new ones without flagging registration requirement
• Recommends virtualized lists (ListView/TileView) before widget pooling for large collections

Coverage Notes

• Case 3 (CommonUI input routing) requires project to have CommonUI configured; test is skipped if project does not use CommonUI
• Case 4 (performance) is a high-impact failure mode — 300ms hitches are shipping-blocking; prioritize this test case
• Case 5 is the most important context-awareness test for UI pipeline consistency
• No automated runner; review manually or via /skill-test