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.

• ID: seo-advanced.crawlability.no-unintended-noindex
• Severity: medium
• What to look for: Count all occurrences of robots: { index: false }, <meta name="robots" content="noindex">, and X-Robots-Tag: noindex across every page component and middleware. For each occurrence, check whether it is guarded by an environment check (e.g., process.env.NODE_ENV !== 'production'). Enumerate any noindex directives on production public pages.
• Pass criteria: Zero noindex directives exist on production public pages. Any noindex usage is guarded by environment checks or applies only to legitimately non-indexable pages (admin, auth). Report: "X noindex directives found; 0 affect production public pages."
• Fail criteria: At least 1 unintended noindex directive on a production public page without an environment guard.
• Do NOT pass when: A noindex directive is present in a shared layout component (e.g., app/layout.tsx) that applies to all pages, even if individual pages don't explicitly set it.
• Skip (N/A) when: Never — accidental noindex is a critical indexation issue that must always be checked.
• Detail on fail: "Blog listing page in app/blog/page.tsx has robots: { index: false } without environment check".
• Remediation: Remove unintended noindex and add environment checks. In app/blog/page.tsx or the affected page component, ensure noindex is conditional on environment.