Imported from vijaygupta18/system-design-simulator (AGENTS.md). Install upstream with npx skills add vijaygupta18/system-design-simulator. Copyright stays with the author.

This is NOT the Next.js you know

This version has breaking changes — APIs, conventions, and file structure may all differ from your training data. Read the relevant guide in node_modules/next/dist/docs/ before writing any code. Heed deprecation notices.

Before you start

• Read CLAUDE.md — it has the architecture map, the engine/scoring/store invariants you must not break, and data conventions. Most subtle bugs here come from violating one of those invariants.
• This app is 100% client-side (no backend). State persists to localStorage via Zustand; hydration is deferred to avoid SSR mismatch.
• Verify with npm run build (runs tsc) and by exercising flows in the browser — there are no unit tests.

Quick rules of thumb

• Don't add runtime dependencies without a strong reason.
• Don't reintroduce: tick-counting timers, inline nodeTypes/edgeTypes, presence-only scoring, hover-only touch affordances, or dropping edge.data on save.
• Keep each scoring category capped at exactly 20 points.
• Dark theme only. No Claude/AI attribution in commit messages.