diff --git a/src/unfold/site/manifest.ts b/src/unfold/site/manifest.ts
index 8eb0fc8..3648886 100644
--- a/src/unfold/site/manifest.ts
+++ b/src/unfold/site/manifest.ts
@@ -1,5 +1,7 @@
 import { DOMParser, type HTMLDocument } from "deno-dom-wasm";
 import { normalizeSiteUrl } from "./site_url.ts";
+import type { VaultNode } from "../inputs/jsonld/types.ts";
+import { loadVault } from "../inputs/jsonld/loader.ts";
 
 type ManifestPage = {
   path: string;
@@ -209,6 +211,15 @@ const requireVaultPath = (value?: string): string => {
   return raw;
 };
 
+/// Unlike its siblings above, this does not throw: `defaultSiteUrl` already
+/// supplies a normalized SITE_URL-or-placeholder, so an absent site URL has a
+/// sensible answer. The fallback argument carries the WebSite node's url when
+/// building from the vault graph.
+const requireSiteUrl = (value?: string, fallback?: string): string => {
+  const raw = value?.trim() || fallback?.trim();
+  return raw ? normalizeSiteUrl(raw) : defaultSiteUrl();
+};
+
 const hasJsonLdType = (node: VaultNode, type: string): boolean => {
   const value = node["@type"];
   if (!value) return false;
diff --git a/src/unfold/site/site_url.ts b/src/unfold/site/site_url.ts
new file mode 100644
index 0000000..9ecb3d6
--- /dev/null
+++ b/src/unfold/site/site_url.ts
@@ -0,0 +1,18 @@
+const stripTrailingSlash = (value: string): string => value.replace(/\/$/, "");
+
+const stripFoldEnginePrefix = (pathname: string): string =>
+  pathname.replace(/^\/fold-engine(?=\/|$)/, "");
+
+export const normalizeSiteUrl = (value: string): string => {
+  const trimmed = stripTrailingSlash(value.trim());
+  try {
+    const url = new URL(trimmed);
+    const normalizedPath = stripFoldEnginePrefix(
+      stripTrailingSlash(url.pathname),
+    );
+    url.pathname = normalizedPath || "/";
+    return stripTrailingSlash(url.toString());
+  } catch {
+    return stripTrailingSlash(stripFoldEnginePrefix(trimmed));
+  }
+};