01-web

A set of rules for building web applications with Next.js 15 and React. It covers where code runs, how data is fetched, how pages are organized, and which design and accessibility practices to follow.

In plain words
What is it for?
Use it when developing pages, route groups, server or client components, API calls, environment variables, and interface components in the specified project.
Why use it?
It gives developers consistent decisions for common web-app structure and avoids mixing incompatible data-fetching patterns. It also keeps secrets out of browser-side code.

Cursor rule

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/wellapp-ai/well/01-web
Clone the repo
git clone --depth 1 https://github.com/WellApp-ai/Well
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 368 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00368
Opus 5 $0.00000 $0.00184
Sonnet 5 $0.00000 $0.00074
Haiku 4.5 $0.00000 $0.00037

Measured 2d ago against content hash 8c773dc2db96, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

01-web scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

cursor-rules/rules/01-web.mdc · 46 lines

What it actually says

Web Rules (Next.js 15)

Server vs Client Components

  • Default to Server Components (no directive needed)
  • Add "use client" ONLY when required:
    • Using hooks (useState, useEffect, useQuery)
    • Event handlers (onClick, onChange)
    • Browser APIs (window, localStorage)
  • Keep client components small; lift data fetching to server parents

Environment Variables

  • NEXT_PUBLIC_* only accessible in client components
  • Server-only secrets: access in server components/route handlers only
  • Use API_CONFIG.BASE_URL (wraps NEXT_PUBLIC_WELL_API_BASE_URL)

Route Groups

  • (dashboard) - Standard chrome with sidebar/nav
  • (fullscreen) - No chrome, for flows like connector installs
  • Route group segments are URL-invisible
  • See /docs/development/web-routing.md for full architecture

Data Fetching

  • Client-side: React Query via query hooks (/lib/queries/)
  • Server components: Direct service calls
  • Never mix patterns in same component

Design System

  • Reference /docs/design-system/ before creating patterns
  • Use Tailwind classes from design tokens only
  • Check shadcn/ui components first (/components/ui/)
  • Verify: keyboard nav, responsive, Accessibility Tree

Storybook

  • Every exported component SHOULD have a story
  • Show states: default, loading, error, empty
  • Run npm run storybook to verify

Internationalization

  • Use useTranslations from next-intl for user-facing text
  • Messages in /src/i18n/messages/en/[namespace].json
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 46 lines · 0 tokens per session scan A 8c773dc2db96

Subscribe to this mod's changes

01-web is a cursor rule published in the GitHub repository WellApp-ai/Well (340 stars, last pushed 25d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 368 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.