diff --git a/packages/sdk/src/adapters/iframe.sync.test.ts b/packages/sdk/src/adapters/iframe.sync.test.ts
index 7b80e2105..cde99bcfd 100644
--- a/packages/sdk/src/adapters/iframe.sync.test.ts
+++ b/packages/sdk/src/adapters/iframe.sync.test.ts
@@ -219,6 +219,21 @@ window.__timelines = { t: tl };</script>
     expect(liveRoot.style.getPropertyValue("--accent")).toBe("#0f0");
   });
 
+  it("mirrors declareVariable/removeVariable onto the live document's schema attribute", async () => {
+    const iframe = mountIframe(BASE_HTML); // no data-composition-variables at all
+    const comp = await openComposition(BASE_HTML);
+    const adapter = createIframePreviewAdapter(iframe);
+    adapter.attachSync(comp);
+
+    comp.declareVariable({ id: "accent", type: "string", label: "Accent", default: "#fff" });
+
+    const liveDocEl = iframe.contentDocument!.documentElement;
+    expect(liveDocEl.getAttribute("data-composition-variables")).toContain("accent");
+
+    comp.removeVariable("accent");
+    expect(liveDocEl.getAttribute("data-composition-variables")).not.toContain("accent");
+  });
+
   it("mirrors setTiming onto the live element's data-start/data-end attributes", async () => {
     const iframe = mountIframe(BASE_HTML);
     const comp = await openComposition(BASE_HTML);
diff --git a/packages/sdk/src/adapters/iframe.ts b/packages/sdk/src/adapters/iframe.ts
index f5c1595f2..e83736b7c 100644
--- a/packages/sdk/src/adapters/iframe.ts
+++ b/packages/sdk/src/adapters/iframe.ts
@@ -754,20 +754,35 @@ class IframePreviewAdapter implements PreviewAdapter {
 
     const doc = this.iframe.contentDocument;
     if (doc) {
-      applyOverrideSet({ document: doc, wrapped: false, stamped: "" }, comp.getOverrides());
+      try {
+        applyOverrideSet({ document: doc, wrapped: false, stamped: "" }, comp.getOverrides());
+      } catch (err) {
+        // Don't let a bad initial snapshot prevent the ongoing subscription
+        // below from attaching — future patches should still mirror even if
+        // this composition's current overrides couldn't be applied.
+        console.warn("[hyperframes] attachSync: initial override sync failed:", err);
+      }
     }
 
-    const unsubscribe = comp.on("patch", ({ patches }) => {
+    const rawUnsubscribe = comp.on("patch", ({ patches }) => {
       const liveDoc = this.iframe.contentDocument;
       if (!liveDoc) return;
       applyPatchesToDocument(
         { document: liveDoc, wrapped: false, stamped: "" },
-        patches.filter((p) => p.path !== "/script/gsap"),
+        // "Never mirror script-tag rewrites" is the documented contract, not
+        // just today's one known path — startsWith so a future script kind
+        // (e.g. "/script/label") is covered by the same intent, not just an
+        // exact string this filter happens to know about today.
+        patches.filter((p) => !p.path.startsWith("/script/")),
       );
     });
 
-    this._syncDetach = unsubscribe;
-    return unsubscribe;
+    const detach = (): void => {
+      rawUnsubscribe();
+      if (this._syncDetach === detach) this._syncDetach = null;
+    };
+    this._syncDetach = detach;
+    return detach;
   }
 }