diff --git a/apps/docs/scripts/auth-cli.ts b/apps/docs/scripts/auth-cli.ts
index 046988a..e06d461 100644
--- a/apps/docs/scripts/auth-cli.ts
+++ b/apps/docs/scripts/auth-cli.ts
@@ -187,17 +187,18 @@ async function main() {
   assert.ok(searchIndex.some((doc: { slug: string; searchText: string }) => doc.slug === "source-studies/pretext/measurement-cache" && doc.searchText.includes("getSegmentMetrics")));
   for (const doc of searchIndex as { slug: string; sourceSlug: string }[]) {
     assert.ok(!doc.slug.split("/").some((part) => /^\d+-/.test(part)), doc.slug);
-    const legacy = await request(`/docs/${doc.sourceSlug}`, { headers });
+    const legacy = await request(`/docs/${doc.sourceSlug}?from=legacy`, { headers });
     assert.equal(legacy.status, 308, doc.sourceSlug);
-    assert.equal(new URL(legacy.headers.get("location")!, base).pathname, `/docs/${doc.slug}`);
+    const destination = new URL(legacy.headers.get("location")!, base);
+    assert.equal(destination.pathname, `/docs/${doc.slug}`);
+    assert.equal(destination.searchParams.get("from"), "legacy");
+    assert.ok(legacy.headers.get("cache-control")?.includes("no-store"));
   }
   let home = "";
   let purpose = "";
   for (const route of routes) {
     const response = await request(route, { headers });
-    const alias = (searchIndex as { sourceSlug: string }[]).some((doc) => route === `/docs/${doc.sourceSlug}`);
-    assert.equal(response.status, alias ? 308 : 200, route);
-    if (alias) continue;
+    assert.equal(response.status, 200, route);
     const html = await response.text();
     if (route === "/") home = html;
     if (route === "/docs/endor/endor-purpose-draft") purpose = html;
diff --git a/apps/docs/src/pages/docs/[...slug].tsx b/apps/docs/src/pages/docs/[...slug].tsx
index a4d7415..5ddb476 100644
--- a/apps/docs/src/pages/docs/[...slug].tsx
+++ b/apps/docs/src/pages/docs/[...slug].tsx
@@ -25,16 +25,14 @@ import { headingsFor } from "@/lib/navigation";
 
 type Props = { doc: Doc; docs: DocLink[] };
 export const getStaticPaths: GetStaticPaths = async () => ({
-  paths: (await listDocs()).flatMap(({ slug, sourceSlug }) => [...new Set([slug, sourceSlug])].map((value) => ({ params: { slug: value.split("/") } }))),
+  paths: (await listDocs()).map(({ slug }) => ({ params: { slug: slug.split("/") } })),
   fallback: false,
 });
 export const getStaticProps: GetStaticProps<Props> = async ({ params }) => {
   const slug = Array.isArray(params?.slug) ? params.slug.join("/") : params?.slug;
   if (typeof slug !== "string") return { notFound: true };
   const docs = await listDocs();
-  const match = docs.find((d) => d.slug === slug || d.sourceSlug === slug);
-  if (!match) return { notFound: true };
-  if (slug !== match.slug) return { redirect: { destination: `/docs/${match.slug}`, permanent: true } };
+  if (!docs.some((d) => d.slug === slug)) return { notFound: true };
   return { props: { doc: await readDoc(slug), docs } };
 };
 function textOf(value: ReactNode): string {
diff --git a/apps/docs/src/proxy.ts b/apps/docs/src/proxy.ts
index 7718d77..021e478 100644
--- a/apps/docs/src/proxy.ts
+++ b/apps/docs/src/proxy.ts
@@ -1,5 +1,10 @@
 import { NextResponse, type NextRequest } from "next/server";
 import { authConfig, SESSION_COOKIE, validSession } from "./lib/auth";
+import catalog from "../../../content/catalog.json";
+
+const legacyRoutes = new Map(Object.entries(catalog.documents).map(([source, metadata]) => [
+  `/docs/${source}`, `/docs/${metadata.slug}`,
+]));
 
 export function proxy(request: NextRequest) {
   const path = request.nextUrl.pathname;
@@ -49,6 +54,13 @@ export function proxy(request: NextRequest) {
         );
       }
     }
+    // Keep legacy URLs behind authentication and out of static generation.
+    const destination = legacyRoutes.get(path);
+    if (destination && ["GET", "HEAD"].includes(request.method)) {
+      const target = request.nextUrl.clone();
+      target.pathname = destination;
+      return NextResponse.redirect(target, { status: 308, headers });
+    }
     return NextResponse.next({ headers });
   }
   if (path.startsWith("/api/") || !["GET", "HEAD"].includes(request.method)) {