What problem does it solve? Unit tests and a compiling view prove UI logic but never prove the screen actually renders correctly — clipped containers, overflowing text, and invisible controls slip past green test suites. This Skill closes that gap when building a ui block in the mismAgent build flow. ## Core Features & Use Cases - Presenter/view split: Separates every screen decision into a plain, unit-testable state-holder/presenter while the view only renders observable state and forwards events. - Mandatory render-check: Requires either an automated smoke/screenshot test from the side's profile gate or a recorded run-the-app check via the run-app-smoke skill, with evidence stored in render-proof/<block-id>/. - Render checklist: Enforces explicit sizing, deliberate overflow handling, contrast/visibility, empty/error/loading state rendering, and observable-state recomposition. - Use Case: When the mismAgent worker loads a block with type = ui, this Skill drives TDD on the presenter from tests_nl, then verifies the screen renders correctly before reporting PUBLIC_API and the render-check result back to the worker. ## Quick Start Ask the mismAgent worker to build the ui block defined in your building-blocks manifest so it realizes the presenter and thin view and records the render-check proof.
