diff --git a/studio/frontend/src/features/chat/runtime-provider.tsx b/studio/frontend/src/features/chat/runtime-provider.tsx
index d01383b309..bdf4e528d8 100644
--- a/studio/frontend/src/features/chat/runtime-provider.tsx
+++ b/studio/frontend/src/features/chat/runtime-provider.tsx
@@ -1017,6 +1017,21 @@ function ActiveThreadSync({
     if (!enabled) {
       return;
     }
+    const persisted = useChatRuntimeStore.getState().activeThreadId;
+    // On page reload aui mints a fresh `__LOCALID_*` for its draft thread.
+    // If we already have a persisted draft id, keep it so any RAG docs
+    // attached to that draft id stay visible — assistant-ui's internal
+    // chat history for the new mainThreadId starts empty either way, so
+    // this only affects what we treat as the active id for doc/RAG lookup.
+    if (
+      mainThreadId
+      && persisted
+      && persisted !== mainThreadId
+      && persisted.startsWith("__LOCALID_")
+      && mainThreadId.startsWith("__LOCALID_")
+    ) {
+      return;
+    }
     setActiveThreadId(mainThreadId ?? null);
   }, [enabled, mainThreadId, setActiveThreadId]);
 
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 1d1df695eb..05c77de896 100644
--- a/studio/frontend/src/features/chat/stores/chat-runtime-store.ts
+++ b/studio/frontend/src/features/chat/stores/chat-runtime-store.ts
@@ -36,6 +36,7 @@ export const CHAT_RAG_TOOL_ENABLED_KEY = "unsloth_chat_rag_tool_enabled";
 // localStorage persistence here the user's external pick is silently
 // reset to the default on every page refresh.
 const LAST_EXTERNAL_CHECKPOINT_KEY = "unsloth_chat_last_external_checkpoint";
+const CHAT_ACTIVE_THREAD_KEY = "unsloth_chat_active_thread_id";
 
 function loadLastExternalCheckpoint(): string | null {
   if (typeof window === "undefined") return null;
@@ -610,7 +611,9 @@ export const useChatRuntimeStore = create<ChatRuntimeStore>((set, get) => ({
   defaultChatTemplate: null,
   chatTemplateOverride: null,
   loadedChatTemplateOverride: null,
-  activeThreadId: null,
+  // Persisted across reloads so RAG documents uploaded under a draft
+  // thread id stay attached after the page refreshes.
+  activeThreadId: loadString(CHAT_ACTIVE_THREAD_KEY, "") || null,
   settingsPanelOpen: false,
   pendingAudioBase64: null,
   pendingAudioName: null,
@@ -755,8 +758,10 @@ export const useChatRuntimeStore = create<ChatRuntimeStore>((set, get) => ({
         activeGgufVariant: ggufVariant ?? null,
       };
     }),
-  setActiveThreadId: (activeThreadId) =>
-    set({ activeThreadId, contextUsage: null }),
+  setActiveThreadId: (activeThreadId) => {
+    saveString(CHAT_ACTIVE_THREAD_KEY, activeThreadId ?? "");
+    set({ activeThreadId, contextUsage: null });
+  },
   setSettingsPanelOpen: (settingsPanelOpen) => set({ settingsPanelOpen }),
   clearCheckpoint: () => {
     // Mirror setCheckpoint's persistence behavior: dropping the