CURSOR RULESNext.js 15 Cursor Rules Generator (.mdc) | Free & Offline
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.
.cursor/rules/nextjs-15.mdcFailure 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 Without explicit cursor rules, LLMs frequently hallucinate outdated pages/ router conventions, unnecessary 'use client' directives, and sync request APIs.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 Cursor Rules (.mdc) via Terminal
Step 1: Open Project Directory & Verify Target Placement
Open your terminal and navigate to your project root folder where the .cursor/rules/nextjs-15.mdc 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 .cursor/rules/nextjs-15.mdc:
Terminal One-Liner Install
Run directly in your project root to stream and write this rule file with one command.
mkdir -p ".cursor/rules" && curl -fsSL "https://www.devscratchpad.tech/api/raw/cursor-rules/nextjs-15" -o ".cursor/rules/nextjs-15.mdc"Step 3: Verify and Activate with AI Agent
Launch your AI coding assistant (Cursor IDE & Composer). The assistant will automatically discover .cursor/rules/nextjs-15.mdc in your repository and apply the architectural guardrails, type constraints, and verification protocols during code generation.
Cursor Rules (.mdc) Directory & Generator
Inspect the complete specification manual, glob patterns, directory rules, and all available presets in our central directory.
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/`.