diff --git a/packages/core/src/studio-api/helpers/previewAdapter.test.ts b/packages/core/src/studio-api/helpers/previewAdapter.test.ts
new file mode 100644
index 000000000..7b5480628
--- /dev/null
+++ b/packages/core/src/studio-api/helpers/previewAdapter.test.ts
@@ -0,0 +1,51 @@
+/**
+ * T10 — PreviewAdapter contract (spec for R7).
+ *
+ * `createPreviewAdapter` does not exist yet. These stubs define the expected
+ * interface so R7 has a concrete target. Convert from it.todo to real
+ * assertions in the R7 PR.
+ *
+ * Hit-testing (elementAtPoint) in both linkedom and jsdom returns null for
+ * all geometry calls — the real tests must inject a position-resolver stub
+ * or mock elementFromPoint. The contract tested is filtering logic (root
+ * exclusion, data-hf-id ancestor walk, opacity-at-playhead), not geometry.
+ */
+import { describe, it } from "vitest";
+
+describe("T10 — PreviewAdapter contract (spec for R7)", () => {
+  describe("elementAtPoint", () => {
+    it.todo("returns null for the stage root (data-hf-root)");
+
+    it.todo("returns the nearest ancestor with data-hf-id");
+
+    it.todo("returns null when the hit element has no data-hf-id ancestor");
+
+    it.todo("skips elements whose computed opacity is 0 at the given playhead time");
+  });
+
+  describe("applyDraft / revertDraft", () => {
+    it.todo("applyDraft writes --hf-studio-* CSS props and sets the gesture marker");
+
+    it.todo("applyDraft accepts both move (dx/dy) and resize (w/h) payloads");
+
+    it.todo("revertDraft removes draft props and clears the gesture marker");
+
+    it.todo("revertDraft restores original translate when an original was recorded");
+  });
+
+  describe("commitPreview", () => {
+    it.todo("returns null when no gesture marker is present");
+
+    it.todo("derives a moveElement patch from draft markers on commit");
+
+    it.todo("derives a resize patch from draft markers on commit");
+
+    it.todo("clears the gesture marker after commit");
+  });
+
+  describe("getElementTimings", () => {
+    it.todo("reads authored absolute times from data-start / data-end");
+
+    it.todo("ignores elements without data-hf-id");
+  });
+});