diff --git a/.playground/nuxt.config.ts b/.playground/nuxt.config.ts
index 4ced7c0..57076d8 100644
--- a/.playground/nuxt.config.ts
+++ b/.playground/nuxt.config.ts
@@ -4,7 +4,9 @@
 // testing/smoke-ssr.mjs builds it against the fixture API. The /blog pages
 // are route-cached (swr) as on a production site, so the smoke and
 // testing/purge-check.mjs see redirects, 410 and purges apply to cached
-// pages. /prywatne/** is declared noindex.
+// pages. /prywatne/** is declared noindex; the HTML sitemap paths follow
+// the fixture site answer (testing/fixtures/seo/site.json), so the startup
+// drift check finds nothing.
 export default defineNuxtConfig({
   extends: ['..'],
   compatibilityDate: '2025-07-15',
@@ -17,5 +19,6 @@ export default defineNuxtConfig({
   },
   seo: {
     noindexRoutes: ['/prywatne/**'],
+    htmlSitemap: { paths: { pl: '/mapa-strony', en: '/en/sitemap' } },
   },
 })
diff --git a/app/composables/useSeoSite.ts b/app/composables/useSeoSite.ts
new file mode 100644
index 0000000..398a853
--- /dev/null
+++ b/app/composables/useSeoSite.ts
@@ -0,0 +1,22 @@
+// The CMS's site answer (pagination form and segments, the home crumb, the
+// HTML sitemap paths, the content URL patterns …), fetched once per page
+// through GET /api/__seo__/site and shared by every caller on the server
+// and in the browser (stable key, so the payload carries it to hydration).
+// `data.value` is null with the layer off, with a backend before SEO
+// v0.2.0 or with the backend down.
+//
+//   const { data: site } = await useSeoSite()
+
+import type { SeoSiteAnswer } from '../utils/types.ts'
+
+export const SEO_SITE_KEY = 'seo-layer:site'
+
+export function useSeoSite() {
+  return useFetch('/api/__seo__/site', {
+    key: SEO_SITE_KEY,
+    transform: (res: { site?: SeoSiteAnswer | null } | null): SeoSiteAnswer | null =>
+      res && typeof res === 'object' && res.site && typeof res.site === 'object' ? res.site : null,
+    default: () => null,
+    dedupe: 'defer',
+  })
+}
diff --git a/lib/options.ts b/lib/options.ts
new file mode 100644
index 0000000..15d917f
--- /dev/null
+++ b/lib/options.ts
@@ -0,0 +1,36 @@
+// The layer's pagination and HTML-sitemap module options normalised for
+// the runtime config (lib/seo-module.ts) and their readers in app and
+// server code. Pure, so `node --test` drives it.
+
+export interface SeoPaginationOption {
+  form: 'query' | 'path'
+  param: string
+  segments: Record<string, string>
+}
+
+export type SeoHtmlSitemapOption = { paths: Record<string, string> } | false
+
+/** The pagination option with its defaults, as the runtime config carries it. */
+export function paginationOption(value: unknown): SeoPaginationOption {
+  const v = value !== null && typeof value === 'object' ? (value as Record<string, unknown>) : {}
+  const segments: Record<string, string> = {}
+  const raw = v.segments !== null && typeof v.segments === 'object' ? (v.segments as Record<string, unknown>) : {}
+  for (const [locale, segment] of Object.entries(raw)) if (typeof segment === 'string' && /^[\p{L}\p{N}_-]+$/u.test(segment)) segments[locale] = segment
+  return {
+    form: v.form === 'path' ? 'path' : 'query',
+    param: typeof v.param === 'string' && /^[A-Za-z0-9_-]+$/.test(v.param) ? v.param : 'page',
+    segments,
+  }
+}
+
+/** The HTML sitemap option: false, or the paths (each '/' plus at least one character). */
+export function htmlSitemapOption(value: unknown): SeoHtmlSitemapOption {
+  if (value === false) return false
+  const v = value !== null && typeof value === 'object' ? (value as Record<string, unknown>) : {}
+  const paths: Record<string, string> = {}
+  const raw = v.paths !== null && typeof v.paths === 'object' ? (v.paths as Record<string, unknown>) : {}
+  for (const [locale, path] of Object.entries(raw)) {
+    if (typeof path === 'string' && /^\/[^?#\s]+$/.test(path) && !path.includes(':') && !path.includes('*')) paths[locale] = path.replace(/\/+$/, '')
+  }
+  return { paths }
+}
diff --git a/lib/routes.ts b/lib/routes.ts
index a530084..707713f 100644
--- a/lib/routes.ts
+++ b/lib/routes.ts
@@ -5,6 +5,21 @@
 // for the route report and the drift check. Pure TypeScript, so
 // `node --test` drives it.
 
+import { flattenPages, isNoindex, pagePattern, type GuardPage } from './guard.ts'
+
+export interface RoutePage extends GuardPage {
+  name?: string
+  meta?: Record<string, unknown>
+  children?: RoutePage[]
+}
+
+export interface RoutePattern {
+  /** A route-rule style pattern: '/blog/:slug', '/docs/**', '/'. */
+  pattern: string
+  /** True when the route ends in a catch-all ('[...slug]'). */
+  catchAll: boolean
+}
+
 /** True when a robots value keeps the page out of the index. */
 export const robotsNoindex = (robots: unknown) => typeof robots === 'string' && /(^|[\s,])(noindex|none)($|[\s,])/i.test(robots)
 
@@ -23,3 +38,47 @@ export function pageMetaRobots(meta: Record<string, unknown> | undefined | null)
   if (meta.requiresAuth === true) return 'noindex, nofollow'
   return null
 }
+
+/** The layer's own HTML sitemap pages, which the CMS knows already. */
+const isLayerPage = (name: unknown) => typeof name === 'string' && name.startsWith('seo-sitemap-')
+
+/**
+ * The paths without parameters that may be indexed, sorted: no page whose
+ * meta keeps it out of the index (requiresAuth, a noindex seo.robots), none
+ * under seo.noindexRoutes, none of the layer's HTML sitemap pages and no
+ * client-only page.
+ */
+export function staticRoutes(pages: readonly RoutePage[], noindexRoutes: readonly string[]): string[] {
+  const out = new Set<string>()
+  for (const page of flattenPages(pages) as Array<RoutePage & { fullPath: string }>) {
+    // A parent with children renders through one of them.
+    if (Array.isArray(page.children) && page.children.some((c) => c.path === '')) continue
+    const path = page.fullPath
+    if (path.includes(':') || path.includes('*')) continue
+    if (page.mode === 'client' || isLayerPage(page.name)) continue
+    if (robotsNoindex(pageMetaRobots(page.meta))) continue
+    if (isNoindex(path, noindexRoutes)) continue
+    out.add(path)
+  }
+  return [...out].sort()
+}
+
+/** Every page's route pattern ('/posts/:slug', '/**' for a catch-all), sorted. */
+export function routePatterns(pages: readonly RoutePage[]): RoutePattern[] {
+  const seen = new Map<string, RoutePattern>()
+  for (const page of flattenPages(pages)) {
+    const pattern = pagePattern(page.fullPath)
+    if (!seen.has(pattern)) seen.set(pattern, { pattern, catchAll: pattern.endsWith('/**') })
+  }
+  return [...seen.values()].sort((a, b) => a.pattern.localeCompare(b.pattern))
+}
+
+/** The body of the server template #seo-routes. */
+export function routesTemplate(staticPaths: readonly string[], patterns: readonly RoutePattern[]): string {
+  return [
+    '// Generated by vue-seo-layer (lib/routes.ts) from the resolved pages.',
+    `export const staticRoutes = ${JSON.stringify(staticPaths)}`,
+    `export const routePatterns = ${JSON.stringify(patterns)}`,
+    '',
+  ].join('\n')
+}
diff --git a/lib/seo-module.ts b/lib/seo-module.ts
index 09ba357..5344aee 100644
--- a/lib/seo-module.ts
+++ b/lib/seo-module.ts
@@ -8,8 +8,10 @@
 // app still uses it: each module reads only its own keys, so the layer's
 // options never use a name nuxt-seo-utils has (enabled, fallbackTitle …).
 
-import { defineNuxtModule, useLogger } from 'nuxt/kit'
+import { addServerTemplate, defineNuxtModule, useLogger } from 'nuxt/kit'
 import { findOffenders, guardMessage, noindexRule, type GuardPage } from './guard.ts'
+import { htmlSitemapOption, paginationOption, type SeoHtmlSitemapOption, type SeoPaginationOption } from './options.ts'
+import { routePatterns, routesTemplate, staticRoutes, type RoutePage } from './routes.ts'
 
 export interface SeoModuleOptions {
   /**
@@ -45,6 +47,25 @@ export interface SeoModuleOptions {
    * build guard then checks nothing. Default true.
    */
   indexable: boolean
+  /**
+   * Report the site's static routes to the CMS's page registry at server
+   * start (D-33). Needs the route-report token (NUXT_SEO_ROUTE_REPORT_TOKEN,
+   * else NUXT_SEO_NOTFOUND_TOKEN). Default true.
+   */
+  routeReport: boolean
+  /**
+   * The pagination URL form the site's routes are built for (D-40): query
+   * (?page=2) or path (/blog/strona/2, the segment per locale). The CMS's
+   * resolve answer wins at runtime; the startup drift check logs a
+   * difference.
+   */
+  pagination: SeoPaginationOption
+  /**
+   * The HTML sitemap pages (D-34), by locale: the overview at the path, a
+   * group at <path>/<group>. false registers none. A path an app page
+   * already has is left to the app.
+   */
+  htmlSitemap: SeoHtmlSitemapOption
 }
 
 export const SEO_MODULE_DEFAULTS: SeoModuleOptions = {
@@ -55,6 +76,9 @@ export const SEO_MODULE_DEFAULTS: SeoModuleOptions = {
   resolveFiles: ['pdf'],
   noindexRoutes: [],
   indexable: true,
+  routeReport: true,
+  pagination: { form: 'query', param: 'page', segments: { pl: 'strona', en: 'page' } },
+  htmlSitemap: { paths: { pl: '/mapa-strony', en: '/sitemap' } },
 }
 
 const strings = (v: unknown): string[] => (Array.isArray(v) ? v.filter((e): e is string => typeof e === 'string' && e !== '') : [])
@@ -72,6 +96,8 @@ export default defineNuxtModule<SeoModuleOptions>({
     // a global ssr: false into a '/**' route rule.
     const ssr = nuxt.options.ssr !== false
     const inlineRouteRules = nuxt.options.experimental?.inlineRouteRules === true
+    const pagination = paginationOption(options.pagination)
+    const htmlSitemap = htmlSitemapOption(options.htmlSitemap)
 
     // requiresAuth and seo are read from definePageMeta at build time, so
     // the route report leaves signed-in and noindex pages out (D-23).
@@ -123,6 +149,17 @@ export default defineNuxtModule<SeoModuleOptions>({
       pages = resolved as GuardPage[]
       guard()
     })
+
+    // The route artefact (#seo-routes) for the route report and the drift
+    // check: written from the resolved pages when Nitro bundles the
+    // server, so no network call happens at build time.
+    addServerTemplate({
+      filename: '#seo-routes',
+      getContents: () => {
+        const resolved = (pages ?? []) as RoutePage[]
+        return routesTemplate(staticRoutes(resolved, noindexRoutes), routePatterns(resolved))
+      },
+    })
     nuxt.hook('nitro:build:before', (nitro) => {
       nitroRules = nitro.options.routeRules as Record<string, unknown>
       if (!checked || nuxt.options.dev) guard()
@@ -141,6 +178,9 @@ export default defineNuxtModule<SeoModuleOptions>({
       resolveFiles: Array.isArray(options.resolveFiles) ? [...options.resolveFiles] : [...SEO_MODULE_DEFAULTS.resolveFiles],
       noindexRoutes,
       indexable,
+      routeReport: options.routeReport !== false,
+      pagination,
+      htmlSitemap,
     }
   },
 })
diff --git a/package.json b/package.json
index 63e233c..b2f4791 100644
--- a/package.json
+++ b/package.json
@@ -9,7 +9,7 @@
     "build:playground": "nuxt build .playground",
     "test": "node --test --test-reporter=tap tests/*.test.ts",
     "dev:prepare": "nuxt prepare .playground",
-    "smoke:ssr": "node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect.txt --no-site && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo.txt && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-off.txt --env NUXT_PUBLIC_SEO_CMS=false && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-off.txt --env NUXT_PUBLIC_SEO_ENABLED=false && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-down.txt --env NUXT_SEO_API_BASE=http://127.0.0.1:1/_seo/api/v1 && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-notoken.txt --env NUXT_SEO_NOTFOUND_TOKEN=",
+    "smoke:ssr": "node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect.txt --no-site && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo.txt && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-off.txt --env NUXT_PUBLIC_SEO_CMS=false && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-off.txt --env NUXT_PUBLIC_SEO_ENABLED=false && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-down.txt --env NUXT_SEO_API_BASE=http://127.0.0.1:1/_seo/api/v1 && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-notoken.txt --env NUXT_SEO_NOTFOUND_TOKEN= && node testing/smoke-ssr.mjs --output .playground/.output --fixtures testing/fixtures --expect testing/expect-seo-drift.txt --site-file site-drift.json --env NUXT_PUBLIC_SEO_ROUTE_REPORT=false",
     "guard:check": "node testing/guard-check.mjs",
     "purge:check": "node testing/purge-check.mjs --output .playground/.output --fixtures testing/fixtures --path /blog/lwia-grzywa && node testing/purge-token-check.mjs --output .playground/.output --fixtures testing/fixtures --path /blog/lwia-grzywa"
   },
diff --git a/server/api/__seo__/site.get.ts b/server/api/__seo__/site.get.ts
new file mode 100644
index 0000000..75bd865
--- /dev/null
+++ b/server/api/__seo__/site.get.ts
@@ -0,0 +1,18 @@
+// GET /api/__seo__/site: the CMS's site answer (GET <apiBase>/site, SEO
+// plugin v0.2.0) through the layer's server and its cache, for useSeoSite()
+// on the server and in the browser. Always 200 with {site: <answer> | null}:
+// null with the layer off, with a backend before v0.2.0 (its /site answers
+// 404) or with a backend that has not answered since start. Never
+// route-cached ('/api/__seo__/**' cache false) and never indexed.
+
+import { seoServerConfig } from '../../lib/config.ts'
+import { siteAnswer } from '../../lib/site.ts'
+
+export default defineEventHandler(async (event) => {
+  setResponseHeaders(event, { 'cache-control': 'no-store', 'x-robots-tag': 'noindex' })
+  const cfg = seoServerConfig(useRuntimeConfig(event))
+  if (!cfg.enabled) return { site: null }
+  const forwarded = event.context.seoForwardedFor as string | undefined
+  const state = await siteAnswer(cfg, forwarded ? { 'x-forwarded-for': forwarded } : {})
+  return { site: state.state === 'ok' ? state.site : null }
+})
diff --git a/server/lib/config.ts b/server/lib/config.ts
index 2d8f726..90f2388 100644
--- a/server/lib/config.ts
+++ b/server/lib/config.ts
@@ -17,8 +17,10 @@ export interface SeoServerConfig {
   resolveCacheTtl: number
   /** Bearer token of POST /notfound (NUXT_SEO_NOTFOUND_TOKEN); empty: no reports. */
   notfoundToken: string
-  /** Bearer token of the route report (33-08); falls back to notfoundToken. */
+  /** Bearer token of the route report; falls back to notfoundToken. */
   routeReportToken: string
+  /** Module option seo.routeReport (NUXT_PUBLIC_SEO_ROUTE_REPORT): report the static routes at start. */
+  routeReport: boolean
   /** Module option seo.rootFiles: serve robots.txt, the sitemaps, llms.txt and the listed root files. */
   rootFiles: boolean
   /** Module option seo.resolveFiles: file extensions the middleware still resolves (['pdf']). */
@@ -74,6 +76,7 @@ export function seoServerConfig(config: unknown): SeoServerConfig {
     resolveCacheTtl: num(seo.resolveCacheTtl, DEFAULT_RESOLVE_CACHE_TTL),
     notfoundToken,
     routeReportToken: str(seo.routeReportToken) || notfoundToken,
+    routeReport: pub.routeReport !== false && pub.routeReport !== 'false',
     rootFiles: pub.rootFiles !== false && pub.rootFiles !== 'false',
     resolveFiles,
   }
diff --git a/server/lib/drift.ts b/server/lib/drift.ts
new file mode 100644
index 0000000..813cc1f
--- /dev/null
+++ b/server/lib/drift.ts
@@ -0,0 +1,84 @@
+// The startup drift check (D-20c, RESEARCH Open Question 9): Nuxt routes
+// and the layer's pagination and HTML-sitemap options are fixed at build
+// time, while the CMS decides content URL patterns, the pagination form and
+// the HTML-sitemap paths. At server start the layer compares the two and
+// logs one warning per mismatch, so an editor's change in the CMS that the
+// frontend does not follow is visible. Pure, so `node --test` drives it.
+
+import { patternCovers } from '../../lib/guard.ts'
+import type { RoutePattern } from '../../lib/routes.ts'
+import type { SeoSiteAnswer } from '../../app/utils/types.ts'
+
+export const DRIFT_PREFIX = '[vue-seo-layer] drift:'
+
+export interface LayerPaginationOption {
+  form: 'query' | 'path'
+  param: string
+  segments: Record<string, string>
+}
+
+export interface DriftInput {
+  site: SeoSiteAnswer
+  routes: readonly RoutePattern[]
+  pagination: LayerPaginationOption
+  /** seo.htmlSitemap.paths, or false when the layer serves no HTML sitemap. */
+  htmlSitemap: Record<string, string> | false
+}
+
+/** A CMS URL pattern in route-rule form: '{slug}' and ':slug' alike become ':slug'. */
+const cmsPattern = (p: string) => p.replace(/\{(\w+)\}/g, ':$1').split('?')[0]!
+
+/**
+ * True when a Nuxt route serves the CMS pattern: a route of the same shape
+ * (a parameter stands for any segment), or a catch-all under a static
+ * prefix ('/docs/**'). A catch-all at the root ('[...slug].vue') is a
+ * generic page renderer and does not count as a route for a content type.
+ */
+export function routeServes(route: RoutePattern, pattern: string): boolean {
+  if (route.catchAll && route.pattern === '/**') return false
+  return patternCovers(route.pattern, cmsPattern(pattern))
+}
+
+/** One message per mismatch between the CMS's site answer and the build. */
+export function driftWarnings(input: DriftInput): string[] {
+  const out: string[] = []
+  const site = input.site ?? {}
+
+  for (const r of Array.isArray(site.routes) ? site.routes : []) {
+    if (!r || typeof r.pattern !== 'string' || r.pattern === '') continue
+    if (!input.routes.some((route) => routeServes(route, r.pattern))) {
+      out.push(`${DRIFT_PREFIX} the CMS's ${r.type || 'content'} URLs (${r.pattern}) match no Nuxt route`)
+    }
+  }
+
+  const p = site.pagination
+  if (p && typeof p === 'object') {
+    const form = p.form === 'path' ? 'path' : p.form === 'query' ? 'query' : null
+    if (form && form !== input.pagination.form) {
+      out.push(`${DRIFT_PREFIX} the CMS paginates in the ${form} form, the layer was built with ${input.pagination.form} (seo.pagination.form)`)
+    } else if (form === 'query' && typeof p.param === 'string' && p.param && p.param !== input.pagination.param) {
+      out.push(`${DRIFT_PREFIX} the CMS's page parameter is ${p.param}, the layer's is ${input.pagination.param} (seo.pagination.param)`)
+    } else if (form === 'path') {
+      for (const [locale, segment] of Object.entries(p.segments ?? {})) {
+        const own = input.pagination.segments[locale]
+        if (typeof segment === 'string' && segment && own !== segment) {
+          out.push(`${DRIFT_PREFIX} the CMS's ${locale} page segment is ${segment}, the layer's is ${own ?? 'unset'} (seo.pagination.segments)`)
+        }
+      }
+    }
+  }
+
+  const html = site.html_sitemap
+  if (html && html.enabled === true && html.paths && typeof html.paths === 'object') {
+    if (input.htmlSitemap === false) {
+      out.push(`${DRIFT_PREFIX} the CMS has an HTML sitemap, the layer serves none (seo.htmlSitemap is false)`)
+    } else {
+      for (const [locale, path] of Object.entries(html.paths)) {
+        if (typeof path !== 'string' || path === '') continue
+        const own = input.htmlSitemap[locale]
+        if (own !== path) out.push(`${DRIFT_PREFIX} the CMS serves the ${locale} HTML sitemap at ${path}, the layer at ${own ?? 'no path'} (seo.htmlSitemap.paths)`)
+      }
+    }
+  }
+  return out
+}
diff --git a/server/lib/routeReport.ts b/server/lib/routeReport.ts
new file mode 100644
index 0000000..7059924
--- /dev/null
+++ b/server/lib/routeReport.ts
@@ -0,0 +1,33 @@
+// The route report (D-33): at server start the layer posts its static
+// routes (#seo-routes, built from the pages) to the SEO plugin's
+// POST /_seo/api/v1/registry/routes with the route-report token, so the
+// CMS's page registry knows every frontend page. Pure helpers for the
+// Nitro plugin server/plugins/seo-route-report.ts, so `node --test` drives
+// them.
+
+/** The plugin's limits: at most 2000 paths of at most 2048 bytes each. */
+export const ROUTE_REPORT_MAX_ROUTES = 2000
+export const ROUTE_REPORT_MAX_BYTES = 2048
+/** The one retry after a failed report waits this long. */
+export const ROUTE_REPORT_RETRY_MS = 60_000
+
+/** The request body: the paths within the plugin's limits. */
+export function routeReportBody(paths: readonly string[]): { routes: string[] } {
+  const routes = paths
+    .filter((p) => typeof p === 'string' && p.startsWith('/') && Buffer.byteLength(p, 'utf8') <= ROUTE_REPORT_MAX_BYTES)
+    .slice(0, ROUTE_REPORT_MAX_ROUTES)
+  return { routes }
+}
+
+/**
+ * What an answer means: sent (2xx), absent (404: a backend without the
+ * page registry, or with both tokens empty; never retried), refused (401 or
+ * 403: the token is wrong; never retried) or retry (no answer, or any other
+ * status: tried once more after ROUTE_REPORT_RETRY_MS).
+ */
+export function routeReportOutcome(status: number | null): 'sent' | 'absent' | 'refused' | 'retry' {
+  if (status !== null && status >= 200 && status < 300) return 'sent'
+  if (status === 404) return 'absent'
+  if (status === 401 || status === 403) return 'refused'
+  return 'retry'
+}
diff --git a/server/plugins/seo-drift.ts b/server/plugins/seo-drift.ts
new file mode 100644
index 0000000..ead61eb
--- /dev/null
+++ b/server/plugins/seo-drift.ts
@@ -0,0 +1,40 @@
+// The startup drift check (D-20c): compares the CMS's content-type URL
+// patterns, pagination form and segments and HTML-sitemap paths (the site
+// answer, GET <apiBase>/site) with the build's routes (#seo-routes) and the
+// layer's seo.pagination and seo.htmlSitemap options, and logs one
+// "[vue-seo-layer] drift: ..." warning per mismatch. It runs once after the
+// plugin returns, never blocks the start and never fails it; a backend
+// without a site answer (before SEO v0.2.0) or one that does not answer is
+// skipped. Off with the layer off or while prerendering.
+
+import { routePatterns } from '#seo-routes'
+import { seoServerConfig } from '../lib/config.ts'
+import { driftWarnings, type LayerPaginationOption } from '../lib/drift.ts'
+import { siteAnswer } from '../lib/site.ts'
+
+export default defineNitroPlugin(() => {
+  if (import.meta.prerender) return
+  const config = useRuntimeConfig()
+  const cfg = seoServerConfig(config)
+  if (!cfg.enabled) return
+  const pub = ((config.public as Record<string, unknown>).seo ?? {}) as {
+    pagination?: LayerPaginationOption
+    htmlSitemap?: { paths?: Record<string, string> } | false
+  }
+  const pagination: LayerPaginationOption = {
+    form: pub.pagination?.form === 'path' ? 'path' : 'query',
+    param: pub.pagination?.param || 'page',
+    segments: { ...(pub.pagination?.segments ?? {}) },
+  }
+  const htmlSitemap = pub.htmlSitemap === false || (pub.htmlSitemap as unknown) === 'false' ? false : { ...(pub.htmlSitemap?.paths ?? {}) }
+
+  setTimeout(async () => {
+    try {
+      const state = await siteAnswer(cfg, {})
+      if (state.state !== 'ok') return
+      for (const warning of driftWarnings({ site: state.site, routes: routePatterns, pagination, htmlSitemap })) console.warn(warning)
+    } catch (err) {
+      console.warn('[vue-seo-layer] drift check failed:', (err as Error)?.message ?? err)
+    }
+  }, 0).unref?.()
+})
diff --git a/server/plugins/seo-route-report.ts b/server/plugins/seo-route-report.ts
new file mode 100644
index 0000000..5714c6c
--- /dev/null
+++ b/server/plugins/seo-route-report.ts
@@ -0,0 +1,51 @@
+// Reports the site's static routes to the CMS's page registry once per
+// server process (D-33): POST <apiBase>/registry/routes with
+// `Authorization: Bearer <route-report token>` and {routes: [path, ...]}.
+// The paths come from the build (#seo-routes): pages without parameters,
+// without the ones whose meta keeps them out of the index (requiresAuth, a
+// noindex seo.robots) and without seo.noindexRoutes. It never delays the
+// start: the report goes out after the plugin returns, a failure (no
+// answer, a 5xx) is tried once more after 60 s, and a 404 (a backend without
+// the registry) or a refused token is logged once and not retried. Nothing
+// is sent with the layer off (seo.cms, public.seo.enabled), with
+// seo.routeReport false, without a token (NUXT_SEO_ROUTE_REPORT_TOKEN, else
+// NUXT_SEO_NOTFOUND_TOKEN) or while prerendering. The token stays in the
+// server-only runtime config and goes to the configured apiBase only.
+
+import { staticRoutes } from '#seo-routes'
+import { seoServerConfig } from '../lib/config.ts'
+import { ROUTE_REPORT_RETRY_MS, routeReportBody, routeReportOutcome } from '../lib/routeReport.ts'
+
+export default defineNitroPlugin(() => {
+  if (import.meta.prerender) return
+  const cfg = seoServerConfig(useRuntimeConfig())
+  if (!cfg.enabled || !cfg.routeReport || !cfg.routeReportToken) return
+  const body = routeReportBody(staticRoutes)
+
+  const send = async (attempt: number): Promise<void> => {
+    let status: number | null = null
+    let reason = ''
+    try {
+      const res = await $fetch.raw('/registry/routes', {
+        baseURL: cfg.apiBase,
+        method: 'POST',
+        body,
+        headers: { authorization: `Bearer ${cfg.routeReportToken}` },
+        timeout: Math.max(cfg.timeoutMs, 5000),
+        ignoreResponseError: true,
+      })
+      status = res.status
+    } catch (err) {
+      reason = (err as Error)?.message ?? String(err)
+    }
+    const outcome = routeReportOutcome(status)
+    if (outcome === 'sent') console.info(`[vue-seo-layer] route report: ${body.routes.length} routes sent`)
+    else if (outcome === 'absent') console.info('[vue-seo-layer] route report: the CMS has no page registry (404), nothing reported')
+    else if (outcome === 'refused') console.warn(`[vue-seo-layer] route report: the CMS refused the token (${status}); set NUXT_SEO_ROUTE_REPORT_TOKEN to golem15.seo.route_report_token`)
+    else if (attempt === 1) {
+      console.warn(`[vue-seo-layer] route report failed (${status ?? reason}); trying again in ${ROUTE_REPORT_RETRY_MS / 1000} s`)
+      setTimeout(() => void send(2), ROUTE_REPORT_RETRY_MS).unref?.()
+    } else console.warn(`[vue-seo-layer] route report failed again (${status ?? reason}); not retried before the next start`)
+  }
+  setTimeout(() => void send(1), 0).unref?.()
+})
diff --git a/server/seo-routes.d.ts b/server/seo-routes.d.ts
new file mode 100644
index 0000000..25985f8
--- /dev/null
+++ b/server/seo-routes.d.ts
@@ -0,0 +1,8 @@
+// The server template the layer's module writes from the resolved pages
+// (lib/routes.ts, addServerTemplate).
+declare module '#seo-routes' {
+  /** Paths without parameters that may be indexed (the route report). */
+  export const staticRoutes: string[]
+  /** Every page's route pattern (the drift check). */
+  export const routePatterns: Array<{ pattern: string; catchAll: boolean }>
+}
diff --git a/testing/expect-seo-drift.txt b/testing/expect-seo-drift.txt
new file mode 100644
index 0000000..6120e89
--- /dev/null
+++ b/testing/expect-seo-drift.txt
@@ -0,0 +1,12 @@
+# The startup drift check against a site answer that differs from the
+# build (testing/fixtures/seo/site-drift.json): a content type whose URL
+# pattern no Nuxt route serves, the path pagination form against the
+# layer's query form and another pl HTML sitemap path. One warning each;
+# the server still starts and serves pages. Run with
+# NUXT_PUBLIC_SEO_ROUTE_REPORT=false, so no route report is sent.
+200 /plain contains=<title>Plain page | Playground</title>
+log [vue-seo-layer] drift::3
+log [vue-seo-layer] drift: the CMS's journal-post URLs (/wpisy/:slug) match no Nuxt route:1
+log [vue-seo-layer] drift: the CMS paginates in the path form, the layer was built with query (seo.pagination.form):1
+log [vue-seo-layer] drift: the CMS serves the pl HTML sitemap at /mapa, the layer at /mapa-strony (seo.htmlSitemap.paths):1
+routereport 0
diff --git a/testing/expect-seo-notoken.txt b/testing/expect-seo-notoken.txt
index 112510e..3ad540c 100644
--- a/testing/expect-seo-notoken.txt
+++ b/testing/expect-seo-notoken.txt
@@ -1,3 +1,5 @@
 # No 404 token (NUXT_SEO_NOTFOUND_TOKEN empty): a 404 page sends no report.
 404 /kontakt
 noreport /kontakt
+# Without a token the route report is not sent either.
+routereport 0
diff --git a/testing/expect-seo.txt b/testing/expect-seo.txt
index 58f3a5a..0ce997e 100644
--- a/testing/expect-seo.txt
+++ b/testing/expect-seo.txt
@@ -75,3 +75,12 @@ noreport /stary
 200 /prywatne contains=<meta name="robots" content="noindex, nofollow"> header=X-Robots-Tag: noindex, nofollow
 200 /plain noheader=X-Robots-Tag count=name="robots":0
 200 /blog/lwia-grzywa contains=<meta name="robots" content="index, follow">
+
+# The site answer through the layer's server, for useSeoSite().
+200 /api/__seo__/site contains="site_url":"https://example.test" header=X-Robots-Tag: noindex
+
+# The route report at server start: the static paths with the token, not
+# the signed-in page, the page with a noindex seo.robots or the declared
+# noindex route. The build matches the site answer: no drift warning.
+routereport 1 has=/ has=/plain has=/about lacks=/konto lacks=/szkic lacks=/prywatne
+log [vue-seo-layer] drift::0
diff --git a/testing/fixture-api.mjs b/testing/fixture-api.mjs
index 0306f55..11c9997 100644
--- a/testing/fixture-api.mjs
+++ b/testing/fixture-api.mjs
@@ -4,11 +4,14 @@
 //   GET  /_seo/api/v1/resolve?url=…        the answer for that exact url from
 //                                          <dir>/seo/resolve.json, then
 //                                          <dir>/resolve.json, else not_found
-//   GET  /_seo/api/v1/site                 <dir>/seo/site.json (404 without the
-//                                          file or with { site: false }: an
-//                                          older backend)
+//   GET  /_seo/api/v1/site                 <dir>/seo/site.json, or <dir>/seo/<siteFile>
+//                                          (404 without the file or with
+//                                          { site: false }: an older backend)
 //   POST /_seo/api/v1/notfound             204 with `Authorization: Bearer <token>`,
 //                                          401 with another token, 404 without one
+//   POST /_seo/api/v1/registry/routes      the route report: the same token rules;
+//                                          404 with { site: false } (an older
+//                                          backend has no page registry)
 //   GET  /_seo/api/v1/verification/<name>  <dir>/verification/<name> or
 //                                          <dir>/seo/verification/<name>, else 404
 //   GET  /robots.txt, /llms.txt,           <dir>/seo/root/<name>, else 404
@@ -52,10 +55,10 @@ function contentType(name) {
 
 /**
  * Starts the fixture API on 127.0.0.1.
- * @param {{ dir: string, port?: number, token?: string, site?: boolean }} opts
+ * @param {{ dir: string, port?: number, token?: string, site?: boolean, siteFile?: string }} opts
  * @returns {Promise<FixtureApi>}
  */
-export function startFixtureApi({ dir, port = 0, token = FIXTURE_NOTFOUND_TOKEN, site = true }) {
+export function startFixtureApi({ dir, port = 0, token = FIXTURE_NOTFOUND_TOKEN, site = true, siteFile = 'site.json' }) {
   /** @type {FixtureRequest[]} */
   const requests = []
   /** @type {Record<string, unknown>} */
@@ -64,7 +67,7 @@ export function startFixtureApi({ dir, port = 0, token = FIXTURE_NOTFOUND_TOKEN,
   let siteAnswer = null
   const load = () => {
     answers = { ...(readJson(join(dir, 'resolve.json')) ?? {}), ...(readJson(join(dir, 'seo', 'resolve.json')) ?? {}) }
-    siteAnswer = site ? readJson(join(dir, 'seo', 'site.json')) : null
+    siteAnswer = site ? readJson(join(dir, 'seo', siteFile)) : null
   }
   load()
 
@@ -103,6 +106,10 @@ export function startFixtureApi({ dir, port = 0, token = FIXTURE_NOTFOUND_TOKEN,
       if (!token) return { status: 404, body: { error: 'not_found' } }
       return req.headers.authorization === `Bearer ${token}` ? { status: 204 } : { status: 401, body: { error: 'unauthorized' } }
     }
+    if (path === '/registry/routes' && req.method === 'POST') {
+      if (!site || !token) return { status: 404, body: { error: 'not_found' } }
+      return req.headers.authorization === `Bearer ${token}` ? { status: 204 } : { status: 401, body: { error: 'unauthorized' } }
+    }
     const v = /^\/verification\/([A-Za-z0-9._-]+)$/.exec(path)
     if (v && req.method === 'GET') {
       for (const file of [join(dir, 'verification', v[1]), join(dir, 'seo', 'verification', v[1])]) {
diff --git a/testing/fixtures/seo/site-drift.json b/testing/fixtures/seo/site-drift.json
new file mode 100644
index 0000000..d7d25af
--- /dev/null
+++ b/testing/fixtures/seo/site-drift.json
@@ -0,0 +1,16 @@
+{
+  "site_url": "https://example.test",
+  "default_locale": "pl",
+  "locales": ["pl", "en"],
+  "unprefixed_locale": "pl",
+  "links": { "new_tab": true },
+  "html_sitemap": { "enabled": true, "paths": { "pl": "/mapa", "en": "/en/sitemap" }, "page_size": 100 },
+  "routes": [
+    { "type": "post", "pattern": "/posts/:slug" },
+    { "type": "journal-post", "pattern": "/wpisy/:slug" }
+  ],
+  "root_files": [],
+  "llms": false,
+  "pagination": { "form": "path", "param": "page", "segments": { "pl": "strona", "en": "page" } },
+  "home_crumb": { "name": "Start", "url": "https://example.test/" }
+}
diff --git a/testing/fixtures/seo/site.json b/testing/fixtures/seo/site.json
index 17316fd..81d436e 100644
--- a/testing/fixtures/seo/site.json
+++ b/testing/fixtures/seo/site.json
@@ -5,7 +5,7 @@
   "unprefixed_locale": "pl",
   "links": { "new_tab": true },
   "html_sitemap": { "enabled": true, "paths": { "pl": "/mapa-strony", "en": "/en/sitemap" }, "page_size": 100 },
-  "routes": [{ "type": "post", "pattern": "/blog/:slug" }],
+  "routes": [{ "type": "post", "pattern": "/posts/:slug" }],
   "root_files": ["google1234.html", "a1b2c3d4e5f60718293a4b5c6d7e8f90.txt"],
   "llms": true,
   "pagination": { "form": "query", "param": "page", "segments": {} },
diff --git a/testing/smoke-ssr.mjs b/testing/smoke-ssr.mjs
index ca95a3c..b9669ee 100644
--- a/testing/smoke-ssr.mjs
+++ b/testing/smoke-ssr.mjs
@@ -2,7 +2,7 @@
 // SSR smoke check: boots the fixture SEO API and the built playground
 // server, then checks each line of an expectations file.
 //
-//   node testing/smoke-ssr.mjs --output <.output dir> --fixtures <dir> --expect <file> [--no-site] [--env KEY=VALUE]...
+//   node testing/smoke-ssr.mjs --output <.output dir> --fixtures <dir> --expect <file> [--no-site] [--site-file NAME] [--env KEY=VALUE]...
 //
 // Expectation grammar, one check per line ('#' starts a comment line):
 //   STATUS PATH [contains=TEXT] [notcontains=TEXT] [count=TEXT:N] [type=PREFIX]
@@ -12,6 +12,12 @@
 //   resolves PATH N   the API has seen exactly N resolve calls for PATH so far
 //                     (PATH * counts every resolve call)
 //   apicalls N        the API has seen exactly N requests so far
+//   routereport N [has=PATH]... [lacks=PATH]...
+//                     exactly N route reports (POST /registry/routes) reached
+//                     the API by the end of the run, each with the token;
+//                     every has= path is in the last one, no lacks= path is
+//   log TEXT:N        the server's output holds exactly N occurrences of TEXT
+//                     (waits up to 3 s for them; N after the last colon)
 // A value runs until the next ` contains=`, ` notcontains=`, ` count=`,
 // ` type=`, ` header=`, ` noheader=`, ` reqheader=` or the end of the line, so
 // it may contain spaces. Every option may repeat on a line and every
@@ -28,8 +34,9 @@
 // must have carried that address (the SSR fetches forward the visitor's
 // x-forwarded-for). The server is started with the fixture's 404 token and
 // the fixture API as NUXT_SEO_API_BASE; --env overrides either. --no-site
-// makes the fixture API answer /site with 404, as a backend before SEO
-// v0.2.0 does.
+// makes the fixture API answer /site (and the route report) with 404, as a
+// backend before SEO v0.2.0 does; --site-file answers /site with another
+// file of <fixtures>/seo.
 //
 // The same approach as vue-faq-layer's testing/smoke-ssr.mjs; plain .mjs
 // with JSDoc types so it runs from node_modules unchanged.
@@ -45,7 +52,7 @@ const OPTION_KEYS = ['contains', 'notcontains', 'count', 'type', 'header', 'nohe
 
 /** @param {string[]} argv */
 function parseArgs(argv) {
-  /** @type {{ output?: string, fixtures?: string, expect?: string, site: boolean, env: Record<string, string> }} */
+  /** @type {{ output?: string, fixtures?: string, expect?: string, site: boolean, siteFile?: string, env: Record<string, string> }} */
   const out = { env: {}, site: true }
   for (let i = 0; i < argv.length; i++) {
     const arg = argv[i]
@@ -58,6 +65,7 @@ function parseArgs(argv) {
     else if (arg === '--fixtures') out.fixtures = next()
     else if (arg === '--expect') out.expect = next()
     else if (arg === '--no-site') out.site = false
+    else if (arg === '--site-file') out.siteFile = next()
     else if (arg === '--env') {
       const kv = next()
       const eq = kv.indexOf('=')
@@ -66,7 +74,7 @@ function parseArgs(argv) {
     } else throw new Error(`unknown argument ${arg}`)
   }
   if (!out.output || !out.fixtures || !out.expect) throw new Error('--output, --fixtures and --expect are required')
-  return /** @type {{ output: string, fixtures: string, expect: string, site: boolean, env: Record<string, string> }} */ (out)
+  return /** @type {{ output: string, fixtures: string, expect: string, site: boolean, siteFile?: string, env: Record<string, string> }} */ (out)
 }
 
 /**
@@ -156,9 +164,10 @@ async function main() {
 
   const reports = lines.filter((l) => l.startsWith('report ')).map((l) => l.slice('report '.length).trim())
   const noreports = lines.filter((l) => l.startsWith('noreport ')).map((l) => l.slice('noreport '.length).trim())
-  const steps = lines.filter((l) => !l.startsWith('report ') && !l.startsWith('noreport '))
-  const api = await startFixtureApi({ dir: resolve(args.fixtures), site: args.site })
-  /** @type {{ url: string, close: () => Promise<void> } | null} */
+  const routeReports = lines.filter((l) => l.startsWith('routereport '))
+  const steps = lines.filter((l) => !l.startsWith('report ') && !l.startsWith('noreport ') && !l.startsWith('routereport '))
+  const api = await startFixtureApi({ dir: resolve(args.fixtures), site: args.site, ...(args.siteFile ? { siteFile: args.siteFile } : {}) })
+  /** @type {{ url: string, close: () => Promise<void>, output: () => string } | null} */
   let nuxt = null
   const failures = /** @type {string[]} */ ([])
   try {
@@ -174,6 +183,15 @@ async function main() {
         if (got !== Number(resolves[2])) failures.push(`${line}: the API saw ${got} resolve calls`)
         continue
       }
+      const log = /^log\s+(.+):(\d+)$/.exec(line)
+      if (log) {
+        const want = Number(log[2])
+        const seen = () => occurrences(nuxt?.output() ?? '', log[1])
+        for (let i = 0; i < 30 && seen() < want; i++) await new Promise((r) => setTimeout(r, 100))
+        if (want === 0) await new Promise((r) => setTimeout(r, 500))
+        if (seen() !== want) failures.push(`${line}: the server output has ${seen()}\n${nuxt?.output() ?? ''}`)
+        continue
+      }
       const calls = /^apicalls\s+(\d+)$/.exec(line)
       if (calls) {
         if (api.requests.length !== Number(calls[1])) failures.push(`${line}: the API saw ${api.requests.length} requests (${api.requests.map((r) => `${r.method} ${r.url}`).join(', ')})`)
@@ -215,6 +233,26 @@ async function main() {
     for (const p of noreports) {
       if (reported().includes(p)) failures.push(`noreport ${p}: a 404 report reached the API`)
     }
+    const routePosts = () => api.requests.filter((r) => r.method === 'POST' && r.url.endsWith('/registry/routes'))
+    for (const line of routeReports) {
+      const m = /^routereport\s+(\d+)((?:\s+(?:has|lacks)=\S+)*)$/.exec(line)
+      if (!m) {
+        failures.push(`${line}: expected "routereport N [has=PATH]... [lacks=PATH]..."`)
+        continue
+      }
+      const want = Number(m[1])
+      for (let i = 0; i < 20 && routePosts().length < want; i++) await new Promise((r) => setTimeout(r, 100))
+      if (want === 0) await new Promise((r) => setTimeout(r, 500))
+      const posts = routePosts()
+      if (posts.length !== want) failures.push(`${line}: the API saw ${posts.length} route reports`)
+      if (posts.some((r) => r.authorization !== `Bearer ${FIXTURE_NOTFOUND_TOKEN}`)) failures.push(`${line}: a route report carried the wrong token`)
+      const last = /** @type {any} */ (posts[posts.length - 1]?.body)?.routes ?? []
+      for (const opt of (m[2] ?? '').trim().split(/\s+/).filter(Boolean)) {
+        const [key, path] = [opt.slice(0, opt.indexOf('=')), opt.slice(opt.indexOf('=') + 1)]
+        if (key === 'has' && !last.includes(path)) failures.push(`${line}: ${path} is not in the report ${JSON.stringify(last)}`)
+        if (key === 'lacks' && last.includes(path)) failures.push(`${line}: ${path} is in the report ${JSON.stringify(last)}`)
+      }
+    }
     if (api.requests.some((r) => r.url.endsWith('/notfound') && r.authorization !== `Bearer ${FIXTURE_NOTFOUND_TOKEN}`)) {
       failures.push('a 404 report carried the wrong token')
     }
diff --git a/tests/routes.test.ts b/tests/routes.test.ts
index ce5ada2..aec0f37 100644
--- a/tests/routes.test.ts
+++ b/tests/routes.test.ts
@@ -1,6 +1,23 @@
 import assert from 'node:assert/strict'
 import test from 'node:test'
-import { pageMetaRobots, robotsNoindex } from '../lib/routes.ts'
+import { htmlSitemapOption, paginationOption } from '../lib/options.ts'
+import { pageMetaRobots, robotsNoindex, routePatterns, routesTemplate, staticRoutes } from '../lib/routes.ts'
+import { DRIFT_PREFIX, driftWarnings, routeServes } from '../server/lib/drift.ts'
+import { ROUTE_REPORT_MAX_ROUTES, routeReportBody, routeReportOutcome } from '../server/lib/routeReport.ts'
+
+const pages = [
+  { path: '/', name: 'index' },
+  { path: '/blog', name: 'blog' },
+  { path: '/posts/:slug()', name: 'posts-slug' },
+  { path: '/:slug(.*)*', name: 'slug' },
+  { path: '/konto', name: 'konto', meta: { requiresAuth: true } },
+  { path: '/szkic', name: 'szkic', meta: { seo: { robots: 'noindex, follow' } } },
+  { path: '/otwarty', name: 'otwarty', meta: { seo: { robots: 'index, follow' } } },
+  { path: '/prywatne', name: 'prywatne' },
+  { path: '/panel', name: 'panel', mode: 'client' },
+  { path: '/mapa-strony', name: 'seo-sitemap-pl' },
+  { path: '/ustawienia', name: 'ustawienia', children: [{ path: '', name: 'ustawienia-index' }, { path: 'profil', name: 'ustawienia-profil' }] },
+]
 
 test('pageMetaRobots: seo.robots, then requiresAuth, else the CMS decides', () => {
   assert.equal(pageMetaRobots({ requiresAuth: true }), 'noindex, nofollow')
@@ -17,3 +34,84 @@ test('robotsNoindex: noindex and none keep a page out', () => {
   assert.equal(robotsNoindex('index, follow'), false)
   assert.equal(robotsNoindex(null), false)
 })
+
+test('staticRoutes: indexable paths without parameters', () => {
+  assert.deepEqual(staticRoutes(pages, ['/prywatne/**']), ['/', '/blog', '/otwarty', '/ustawienia', '/ustawienia/profil'])
+})
+
+test('routePatterns: page paths as patterns, catch-alls marked', () => {
+  const out = routePatterns(pages)
+  assert.deepEqual(out.find((p) => p.pattern === '/posts/:slug'), { pattern: '/posts/:slug', catchAll: false })
+  assert.deepEqual(out.find((p) => p.pattern === '/**'), { pattern: '/**', catchAll: true })
+  assert.equal(new Set(out.map((p) => p.pattern)).size, out.length)
+})
+
+test('routesTemplate: an ES module with both lists', () => {
+  const src = routesTemplate(['/'], [{ pattern: '/', catchAll: false }])
+  assert.match(src, /export const staticRoutes = \["\/"\]/)
+  assert.match(src, /export const routePatterns = \[\{"pattern":"\/","catchAll":false\}\]/)
+})
+
+test('routeReportBody: within the plugin limits', () => {
+  assert.deepEqual(routeReportBody(['/', '/blog', 'nope', '/' + 'a'.repeat(2048)]).routes, ['/', '/blog'])
+  assert.equal(routeReportBody(Array.from({ length: 2500 }, (_, i) => `/p${i}`)).routes.length, ROUTE_REPORT_MAX_ROUTES)
+})
+
+test('routeReportOutcome: sent, absent, refused or one retry', () => {
+  assert.equal(routeReportOutcome(204), 'sent')
+  assert.equal(routeReportOutcome(200), 'sent')
+  assert.equal(routeReportOutcome(404), 'absent')
+  assert.equal(routeReportOutcome(401), 'refused')
+  assert.equal(routeReportOutcome(403), 'refused')
+  assert.equal(routeReportOutcome(503), 'retry')
+  assert.equal(routeReportOutcome(null), 'retry')
+})
+
+test('options: pagination and HTML sitemap with their checks', () => {
+  assert.deepEqual(paginationOption({ form: 'path', param: 'p', segments: { pl: 'strona', en: 'a b' } }), { form: 'path', param: 'p', segments: { pl: 'strona' } })
+  assert.deepEqual(paginationOption(undefined), { form: 'query', param: 'page', segments: {} })
+  assert.equal(htmlSitemapOption(false), false)
+  assert.deepEqual(htmlSitemapOption({ paths: { pl: '/mapa-strony/', en: 'sitemap', de: '/x/:id' } }), { paths: { pl: '/mapa-strony' } })
+})
+
+const layer = { pagination: { form: 'query' as const, param: 'page', segments: { pl: 'strona', en: 'page' } }, htmlSitemap: { pl: '/mapa-strony', en: '/en/sitemap' } }
+const routes = routePatterns(pages)
+
+test('routeServes: a route of the same shape or a prefixed catch-all; not the root catch-all', () => {
+  assert.equal(routeServes({ pattern: '/posts/:slug', catchAll: false }, '/posts/:id'), true)
+  assert.equal(routeServes({ pattern: '/posts/:slug', catchAll: false }, '/posts/{slug}'), true)
+  assert.equal(routeServes({ pattern: '/docs/**', catchAll: true }, '/docs/:a/:b'), true)
+  assert.equal(routeServes({ pattern: '/**', catchAll: true }, '/wpisy/:slug'), false)
+})
+
+test('driftWarnings: nothing when the CMS and the build agree', () => {
+  const site = {
+    routes: [{ type: 'post', pattern: '/posts/:slug' }],
+    pagination: { form: 'query' as const, param: 'page', segments: {} },
+    html_sitemap: { enabled: true, paths: { pl: '/mapa-strony', en: '/en/sitemap' } },
+  }
+  assert.deepEqual(driftWarnings({ site, routes, ...layer }), [])
+})
+
+test('driftWarnings: one warning per mismatch', () => {
+  const site = {
+    routes: [{ type: 'journal-post', pattern: '/wpisy/:slug' }],
+    pagination: { form: 'path' as const, param: 'page', segments: { pl: 'strona' } },
+    html_sitemap: { enabled: true, paths: { pl: '/mapa', en: '/en/sitemap' } },
+  }
+  const out = driftWarnings({ site, routes, ...layer })
+  assert.equal(out.length, 3)
+  assert.ok(out.every((w) => w.startsWith(DRIFT_PREFIX)))
+  assert.match(out[0]!, /journal-post URLs \(\/wpisy\/:slug\) match no Nuxt route/)
+  assert.match(out[1]!, /path form/)
+  assert.match(out[2]!, /pl HTML sitemap at \/mapa/)
+})
+
+test('driftWarnings: segments and param, a switched-off layer sitemap, a switched-off CMS sitemap', () => {
+  const pathLayer = { ...layer, pagination: { form: 'path' as const, param: 'page', segments: { pl: 'strona' } } }
+  assert.equal(driftWarnings({ site: { pagination: { form: 'path', segments: { pl: 'str' } } }, routes, ...pathLayer }).length, 1)
+  assert.equal(driftWarnings({ site: { pagination: { form: 'query', param: 'p' } }, routes, ...layer }).length, 1)
+  assert.equal(driftWarnings({ site: { html_sitemap: { enabled: true, paths: { pl: '/mapa-strony' } } }, routes, ...layer, htmlSitemap: false }).length, 1)
+  assert.deepEqual(driftWarnings({ site: { html_sitemap: { enabled: false, paths: { pl: '/x' } } }, routes, ...layer }), [])
+  assert.deepEqual(driftWarnings({ site: {}, routes, ...layer }), [])
+})