Add disable_seo config to keep preview deployments out of search engines

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -827,6 +827,25 @@ const config: BunextConfig = {
 
 To serve it from a route instead, `bunext.bunextGenerateRobotsTxt()` takes the same options except `output` and returns the text.
 
+### Disabling SEO
+
+For preview or test deployments that must never be indexed, set `disable_seo`:
+
+```ts
+// bunext.config.ts
+const config: BunextConfig = {
+    disable_seo: process.env.PREVIEW === "true",
+};
+```
+
+With it on, the server:
+
+- adds `X-Robots-Tag: noindex, nofollow` to every response (pages, API routes and files),
+- renders `<meta name="robots" content="noindex, nofollow">` on every page, replacing any `meta.robots`,
+- answers `/robots.txt` with `Disallow: /` for all crawlers, ignoring `public/robots.txt`.
+
+Nothing is written to disk, so the same build can be deployed to production with the option off. Responses returned directly by [middleware](#middleware) are left untouched.
+
 ---
 
 ## Static Files
@@ -971,6 +990,7 @@ export default config;
 | `serverOptions`      | `ServeOptions`                                                                    | —                | Extra options passed to `Bun.serve()` (excluding `fetch`) — see [Server Options](#server-options) |
 | `sitemap`            | `BunextSitemapConfig`                                                             | —                | Options for `bunext sitemap` — see [Sitemap](#sitemap)                                            |
 | `robots`             | `BunextRobotsConfig \| false`                                                     | —                | robots.txt options for `bunext sitemap`, or `false` to skip it — see [robots.txt](#robotstxt)     |
+| `disable_seo`        | `boolean`                                                                         | `false`          | Keep the whole site out of search engines (e.g. preview deployments) — see [Disabling SEO](#disabling-seo) |
 
 ### Middleware