diff --git a/release-gate/local-stack.mjs b/release-gate/local-stack.mjs
index 47aa056..3d00555 100644
--- a/release-gate/local-stack.mjs
+++ b/release-gate/local-stack.mjs
@@ -283,6 +283,15 @@ export async function createLocalGateStack({
     fsp.mkdir(storageRoot, { recursive: true }),
     fsp.mkdir(publishRoot, { recursive: true }),
   ]);
+  // Keep the H5 root writable and isolated so packaged-runtime smoke tests
+  // cannot materialize MindSpace pages inside the candidate artifact. The
+  // platform skill catalog still comes from the packaged runtime via a
+  // read-only symlink.
+  await fsp.symlink(
+    path.join(resolvedPortalRoot, 'skills'),
+    path.join(sandboxRoot, 'skills'),
+    'dir',
+  );
   const wechatBundle = path.join(resolvedPortalRoot, 'wechat-mp.bundle.mjs');
   if (await fsp.stat(wechatBundle).catch(() => null)) {
     await fsp.copyFile(wechatBundle, path.join(sandboxRoot, 'wechat-mp.bundle.mjs'));
@@ -350,11 +359,9 @@ export async function createLocalGateStack({
         baseEnv.MINDSPACE_USERDATA_MCP_PG_URL,
         pgDatabase,
       ),
-      // Keep the packaged runtime root as the code/skill root. Persistent data
-      // is isolated independently below; pointing H5_ROOT at the empty sandbox
-      // makes listPlatformSkillCatalog() see no skills and silently removes
-      // static_publish/page-data tools from ordinary users.
-      MEMIND_PORTAL_H5_ROOT: resolvedPortalRoot,
+      // Keep code and packaged skills available while isolating all writable
+      // H5/MindSpace state from the candidate runtime artifact.
+      MEMIND_PORTAL_H5_ROOT: sandboxRoot,
       H5_USERS_ROOT: usersRoot,
       MINDSPACE_STORAGE_ROOT: storageRoot,
       MEMIND_SHARED_PUBLISH_ROOT: publishRoot,
diff --git a/release-gate/release-script.test.mjs b/release-gate/release-script.test.mjs
index d43de39..a7aa5b4 100644
--- a/release-gate/release-script.test.mjs
+++ b/release-gate/release-script.test.mjs
@@ -47,7 +47,7 @@ test('packaged runtime gate isolates persistent roots and rejects artifact mutat
     path.join(ROOT, 'release-gate', 'local-stack.mjs'),
     'utf8',
   );
-  assert.match(localStackSource, /MEMIND_PORTAL_H5_ROOT: resolvedPortalRoot/);
+  assert.match(localStackSource, /MEMIND_PORTAL_H5_ROOT: sandboxRoot/);
   assert.match(localStackSource, /MEMIND_DEEPSEEK_DISABLE_THINKING: '0'/);
   assert.match(localStackSource, /H5_USERS_ROOT: usersRoot/);
   assert.match(localStackSource, /MINDSPACE_STORAGE_ROOT: storageRoot/);