No unintended noindex tags or X-Robots-Tag headers on indexable pages

A stray robots: { index: false } in app/layout.tsx or a middleware-injected X-Robots-Tag: noindex header can deindex the entire site overnight without any code deploying fresh errors — the most common cause is a staging-guard that was never environment-gated. Once pages drop from the index, recovery takes weeks even after the tag is removed, and organic revenue vanishes during the wait.

Gate every noindex directive on process.env.VERCEL_ENV !== 'production' and keep the guard co-located with the directive. In app/layout.tsx:

export const metadata = {
  robots: process.env.VERCEL_ENV === 'production' ? undefined : { index: false, follow: false }
}

Add a CI check that greps for unguarded noindex strings before merge.