Frontend Development Skill

Mission

Deliver production-ready SvelteKit 2 + Svelte 5 experiences that stay aligned with Skeleton UI, Encore API types, and founder rules. This skill keeps the top-level workflow lean while the references provide deep dives for setup, patterns, and debugging.

When to Use

• Designing or implementing new routes, layouts, and components
• Auditing Svelte 5 rune usage before debugging or code review
• Syncing Encore client updates with frontend behavior
• Preparing UI handoffs, demos, or regression fixes

Development Loop

1. Confirm stack + environment – Follow references/setup-and-config.md to verify packages, project structure, and Skeleton theme config.
2. Plan the feature – Identify required routes, data needs, and component boundaries; capture notes in Graphiti.
3. Implement with runes – Use $state, $derived, $effect, $props, and $bindable patterns from references/svelte5-patterns.md.
4. Compose UI – Apply Skeleton v4 components, Tailwind tokens, and AutoAnimate helpers as documented in references/ui-patterns.md.
5. Integrate Encore client – Regenerate clients (task founder:workflows:regen-client) and rely on typed calls; never use manual fetch.
6. Validate + test – Run the quick command set below, then escalate to e2e Playwright flows via e2e-testing_skill if needed.
7. Document + handoff – Update Graphiti with new patterns, refresh specs, and capture screenshots for stakeholders.

Quick Command Set

# Development
cd frontend && bun run dev

# Quality gates
cd frontend && bun run check      # Svelte + TS
cd .cursor && task frontend:lint  # Biome
cd .cursor && task frontend:test  # Unit/component tests

# After backend API changes
cd .cursor && task founder:workflows:regen-client

Quality Gates (Complete Before Handoff)

• Uses Svelte 5 runes exclusively (let for mutable runes, no legacy $: reactivity)
• Skeleton UI components or Tailwind utility tokens instead of bespoke CSS
• Encore-generated client for every backend call (no manual fetch)
• Explicit TypeScript types, zero any
• No console.log in committed code
• American English spelling (canceled, color, optimize)
• bun run build passes locally before requesting review

Reference Library

• references/setup-and-config.md – Package requirements, Skeleton theme wiring, project structure, Vite configuration
• references/svelte5-patterns.md – Rune usage, prop handling, Encore client integration, file-based routing
• references/ui-patterns.md – Skeleton component catalog, Tailwind tokens, AutoAnimate recipes, reusable component snippets, anti-patterns
• references/debugging-and-quality.md – Debugging signals, hydration checks, rune diagnostics, expanded quality checklist

Related Skills

• frontend-debugging_skill – 10-phase investigation workflow for UI regressions
• e2e-testing_skill – Playwright-first regression strategy once UI flow is ready for automation
• backend-development_skill – Backend integration patterns that frontend components depend on

Notes

• Keep SKILL.md lean (<300 lines). Move deep explanations, code samples, and setup scripts into references/, scripts/, or assets/ folders.
• Update Graphiti with new UI patterns or decisions so other vibes can reuse the knowledge.
• Re-run task founder:rules:check before sharing large UI changes.