diff --git a/scripts/test-webmcp.mjs b/scripts/test-webmcp.mjs
index 37d5747c..c1277ba0 100644
--- a/scripts/test-webmcp.mjs
+++ b/scripts/test-webmcp.mjs
@@ -35,6 +35,44 @@ async function loadTools(fetch) {
   return tools;
 }
 
+for (const origin of [
+  "https://preview.example.pages.dev",
+  "http://localhost:4321",
+]) {
+  test(`topic reads use the current deployment at ${origin}`, async () => {
+    const page = manifest.pages[0];
+    const path = `/spec/${page.category}/${page.slug}.md`;
+    const markdown = readFileSync(
+      new URL(`../dist${path}`, import.meta.url),
+      "utf8",
+    );
+    const requests = [];
+    const tools = await loadTools(async (url) => {
+      // Resolve from a nested page and enforce the deployed connect-src 'self'.
+      const resolved = new URL(
+        url,
+        `${origin}/spec/${page.category}/${page.slug}/`,
+      );
+      requests.push(resolved.href);
+      if (resolved.origin !== origin)
+        throw new TypeError("Blocked cross-origin fetch");
+      if (resolved.pathname === "/webmcp-manifest.json") return response();
+      assert.equal(resolved.pathname, path);
+      return { ok: true, text: async () => markdown };
+    });
+
+    const result = await tools.get_topic.execute({
+      slug: page.slug,
+      limit: 500,
+    });
+    assert.equal(result, markdown);
+    assert.deepEqual(requests, [
+      `${origin}/webmcp-manifest.json`,
+      `${origin}${path}`,
+    ]);
+  });
+}
+
 for (const cancelledCaller of ["first", "second"]) {
   test(`cancelling the ${cancelledCaller} caller leaves the shared fetch usable`, async () => {
     let finish;
diff --git a/src/lib/webmcp.ts b/src/lib/webmcp.ts
index fe91712e..30490114 100644
--- a/src/lib/webmcp.ts
+++ b/src/lib/webmcp.ts
@@ -570,7 +570,7 @@ export async function webmcpManifest() {
         summary: e.data.summary,
         order: e.data.order,
         url: `${site.url}/spec/${e.data.category}/${slug}/`,
-        mdUrl: `${site.url}/spec/${e.data.category}/${slug}.md`,
+        mdUrl: `/spec/${e.data.category}/${slug}.md`,
       };
     })
     .sort(