diff --git a/studio/frontend/src/features/chat/stores/chat-runtime-store.ts b/studio/frontend/src/features/chat/stores/chat-runtime-store.ts
index 287dd1fa8b..1f7442ccd2 100644
--- a/studio/frontend/src/features/chat/stores/chat-runtime-store.ts
+++ b/studio/frontend/src/features/chat/stores/chat-runtime-store.ts
@@ -627,6 +627,17 @@ export const useChatRuntimeStore = create<ChatRuntimeStore>((set, get) => ({
       if (state.settingsHydrated && hasKeys(changedParams)) {
         saveSettingsPatch({ inferenceParams: changedParams });
       }
+      // chat-page picks an external model by mutating `params.checkpoint`
+      // through this setter (not through `setCheckpoint`), so the
+      // localStorage mirror needs to be refreshed here too. Otherwise
+      // the persisted slot stays empty and a refresh falls back to
+      // whatever the backend's `/api/inference/status.active_model`
+      // returns -- usually the previously loaded local model.
+      if (params.checkpoint !== state.params.checkpoint) {
+        saveLastExternalCheckpoint(
+          isExternalModelId(params.checkpoint) ? params.checkpoint : null,
+        );
+      }
       return { params };
     }),
   setCustomPresets: (customPresets) =>