AI RULEBOOKNext.js 15 App Router Windsurf Cascade Rules
Production-grade architectural rulebook for Next.js 15 App Router. Engineered to eliminate LLM hallucinations, enforce strict deterministic conventions, and prevent architectural drift across Cursor IDE, Claude Code CLI, and autonomous multi-agent pipelines.
.windsurf/rules/nextjs-15.mdFailure Patterns Prevented for Next.js 15 App Router
Next.js 15 introduces asynchronous cookies/headers, strict caching defaults (uncached fetch by default), and Server Actions. Without explicit cursor rules, LLMs frequently hallucinate outdated pages/ router conventions, unnecessary 'use client' directives, and sync request APIs.
- Invokes deprecated or removed APIs from older model training weights
- Generates conflicting configuration files and invalid imports
- Silently drops type-safety, boundaries, or transaction isolation
Code Standards: Anti-Pattern vs Verified Implementation
"use client";
export function SaveItem() {
const submit = async (e: any) => {
e.preventDefault();
await fetch("/api/items", { method: "POST", body: JSON.stringify({ title: "Test" }) });
};
return <button onClick={submit}>Save</button>;
}"use server";
import { z } from "zod";
import { db } from "@/lib/db";
const Schema = z.object({ title: z.string().min(3) });
export async function createItem(formData: FormData) {
const parsed = Schema.safeParse(Object.fromEntries(formData));
if (!parsed.success) return { ok: false, errors: parsed.error.flatten().fieldErrors };
await db.item.create({ data: parsed.data });
return { ok: true };
}How to Install Next.js 15 App Router Windsurf Cascade Rules via Terminal
Step 1: Open Project Directory & Verify Target Placement
Open your terminal and navigate to your project root folder where the .windsurf/rules/nextjs-15.md file will reside. Ensure the file is placed at the exact path below relative to your project root so the AI engine automatically loads it:
Step 2: Fetch Rule File via Terminal Command
Run curl, PowerShell, or wget to stream the rule directly from the DevScratchpad raw API endpoint and write it to .windsurf/rules/nextjs-15.md:
Terminal One-Liner Install
Run directly in your project root to stream and write this rule file with one command.
mkdir -p ".windsurf/rules" && curl -fsSL "https://www.devscratchpad.tech/api/raw/windsurf-rules/nextjs-15" -o ".windsurf/rules/nextjs-15.md"Step 3: Verify and Activate with AI Agent
Launch your AI coding assistant (Universal AI Assistants). The assistant will automatically discover .windsurf/rules/nextjs-15.md in your repository and apply the architectural guardrails, type constraints, and verification protocols during code generation.
Windsurf Cascade Rules Directory & Generator
Inspect the complete specification manual, glob patterns, directory rules, and all available presets in our central directory.
Pair With Next.js 15 App Router Client-Side Utilities
100% private, browser-based utilities to test, format, and inspect code generated by your AI rules.
JSON to TypeScript Interfaces
Instantly infer TypeScript interfaces and types from a JSON payload.
JSON to Zod Schema
Infer Zod validation schemas directly from JSON payloads.
SVG to JSX Converter
Convert raw SVG markup into React JSX/TSX components.
JWT Decoder & Inspector
Decode JSON Web Tokens securely. Inspect claims, header, and signature status locally.
Migrating from Legacy .cursorrules or CLAUDE.md?
Use our free, offline converter to transform monolithic rulebooks into modular Cursor .mdc, Claude SKILL.md, and Windsurf Cascade rules.
Technical FAQ: Next.js 15 App Router AI Rulebooks
Why do I need specific Cursor rules for Next.js 15?
Next.js 15 changes key assumptions: asynchronous headers/cookies, un-cached fetch by default, and React 19 hooks. MDC rules ensure Cursor generates compliant modern code rather than legacy Next.js 13/14 or pages/ router patterns.
Where do I save this .mdc file?
Save it to `.cursor/rules/nextjs-15.mdc` in your project root. Cursor will automatically attach it when editing files under `src/app/`.