seldon

You are an accessibility expert specializing in WCAG compliance, inclusive design, and assistive technology compatibility. Conduct audits, identify barriers, and provide remediation guidance.

Find and prioritize branch-coverage weak spots from Vitest reports, then propose targeted tests that improve confidence without broad churn.

Keep TS/TSX/JS/JSX modules under the 200-line AGENTS.md guideline by splitting large components into focused hooks, view parts, and utilities without behavior regressions.

Enforce repo JSX rendering conventions by replacing condition-and patterns with explicit ternary-plus-null rendering where appropriate.

Normalize TypeScript import style and type usage to repo conventions including type-only imports, import ordering, and Array generic preference.

Build accessible design systems with Radix UI primitives. Headless component customization, theming strategies, and compound component patterns for production-grade UI libraries.

Reduce SCSS specificity debt by eliminating unnecessary !important usage, improving selector strategy, and documenting justified exceptions.

Phillips Seldon design system — React components in src/components and src/patterns, co-located Storybook and Vitest, SCSS with $px BEM prefix. Use for library work, Agent Review on UI components, and code review in this repo. Canonical project rules live here plus AGENTS.md and docs/agents/*.

Enforce Storybook coverage expectations for visual components and subcomponents in src/components and src/patterns with explicit parent-coverage exceptions.

Modernize tests from fireEvent-heavy patterns to userEvent-first interactions in Vitest + Testing Library while preserving intent and reducing flake.

Enforce co-located Vitest coverage for UI modules, distinguishing true test gaps from modules intentionally validated through parent component tests.

React composition patterns that scale. Use when refactoring components with boolean prop proliferation, building flexible component libraries, or designing reusable APIs. Triggers on tasks involving compound components, render props, context providers, or component architecture. Includes React 19 API changes.

React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.

Master React, Vue, and Svelte component patterns including CSS-in-JS, composition strategies, and reusable component architecture. Use when building UI component libraries, designing component APIs, or implementing frontend design systems.