diff --git a/package.json b/package.json
index 6a868f1..b816d96 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "@mulmocast/types": "^2.1.36",
     "gui-chat-protocol": "^0.0.3",
     "mulmocast": "^2.1.17",
     "mulmocast-viewer": "^0.1.11",
diff --git a/src/vue/View.vue b/src/vue/View.vue
index 483535e..d8e607f 100644
--- a/src/vue/View.vue
+++ b/src/vue/View.vue
@@ -120,7 +120,8 @@ import { ref, computed, onUnmounted, watch } from "vue";
 import { v4 as uuidv4 } from "uuid";
 import type { ToolResult } from "gui-chat-protocol";
 import type { MulmocastToolData } from "../core/types";
-import { MulmoViewer, type ViewerData } from "mulmocast-viewer";
+import { MulmoViewer } from "mulmocast-viewer";
+import type { MulmoViewerData } from "@mulmocast/types";
 
 const props = defineProps<{
   selectedResult: ToolResult<MulmocastToolData> | null;
@@ -147,7 +148,7 @@ const editableScript = ref(
 );
 
 // MulmoViewer state
-const viewerData = ref<ViewerData | null>(null);
+const viewerData = ref<MulmoViewerData | null>(null);
 // const viewerRef = ref<InstanceType<typeof MulmoView> | null>(null);
 const audioLang = ref("en");
 const textLang = ref("en");
@@ -274,7 +275,7 @@ watch(
         throw new Error("Failed to load viewer JSON");
       }
 
-      viewerData.value = (await response.json()) as ViewerData;
+      viewerData.value = (await response.json()) as MulmoViewerData;
     } catch (error) {
       console.error("Viewer JSON loading failed:", error);
       viewerData.value = null;
diff --git a/yarn.lock b/yarn.lock
index 6dd69f5..c5a1771 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -688,6 +688,13 @@
   resolved "https://registry.yarnpkg.com/@mozilla/readability/-/readability-0.6.0.tgz#134e3ce3ff1676716e550de0b8de957bcc59208b"
   integrity sha512-juG5VWh4qAivzTAeMzvY9xs9HY5rAcr2E4I7tiSSCokRFi7XIZCAu92ZkSTsIj1OPceCifL3cpfteP3pDT9/QQ==
 
+"@mulmocast/types@^2.1.36":
+  version "2.1.36"
+  resolved "https://registry.yarnpkg.com/@mulmocast/types/-/types-2.1.36.tgz#21fa83289fbc8bb60cd1bdbe3905f43b09bb3eff"
+  integrity sha512-ftr+hKgZHmGNQUhd7yVxGyOZwWe3/KA251tWfe5lxjcEeZV4tAlUA1C8p3zd4Qp32Jp2cjHwGUvZi7PEJrv4qw==
+  dependencies:
+    zod "^4.3.5"
+
 "@napi-rs/wasm-runtime@^1.1.0":
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/@napi-rs/wasm-runtime/-/wasm-runtime-1.1.1.tgz#c3705ab549d176b8dc5172723d6156c3dc426af2"