Why it matters
Without a sitemap crawlers discover pages only through links, new or deep pages are indexed slowly and lastmod hints for recrawling are lost.
How to fix it
Add app/sitemap.ts returning every canonical URL with a real lastModified.
Example
import type { MetadataRoute } from 'next'
export default function sitemap(): MetadataRoute.Sitemap {
return [{ url: 'https://example.com/', lastModified: '2026-09-01' }]
}References
More lint rules
void lint reports 67 rules in this category. Static source checks with no browser: Tailwind v4 silent failures, Next.js 16 API traps, React render-body bugs, accessibility markup, SEO files and motion hygiene.
missing-metadata-baseRoot layout metadata has no `metadataBase`canonical-in-root-layoutCanonical URL set in the root layoutog-merge-drops-parentPage `openGraph` replaces the layout's (shallow merge drops images/siteName)not-found-in-suspense`notFound()`/`redirect()` inside a component rendered under `<Suspense>`missing-robotsNo robots.txtmissing-og-imageNo Open Graph image anywheremissing-iconNo favicon / app iconmissing-llms-txtNo `/llms.txt`