diff --git a/yuthon_ai_agent/controllers/main.py b/yuthon_ai_agent/controllers/main.py
index 2899e8b0e..cc7a0a581 100644
--- a/yuthon_ai_agent/controllers/main.py
+++ b/yuthon_ai_agent/controllers/main.py
@@ -212,7 +212,6 @@ class AiChatController(http.Controller):
             'name': filename,
             'mimetype': mimetype,
             'raw': raw_bytes,
-            'folder_id': False,
         })
 
         # OCR 提取文字
diff --git a/yuthon_ai_agent/static/src/js/ai_chat_action.js b/yuthon_ai_agent/static/src/js/ai_chat_action.js
index d96394795..81e78b8e2 100644
--- a/yuthon_ai_agent/static/src/js/ai_chat_action.js
+++ b/yuthon_ai_agent/static/src/js/ai_chat_action.js
@@ -93,7 +93,21 @@ export class AiChatAction extends Component {
             const resp = await fetch("/ai/attachment/upload", {
                 method: "POST",
                 body: formData,
+                credentials: "same-origin",
             });
+            if (!resp.ok) {
+                let detail = "";
+                try {
+                    const errData = await resp.json();
+                    detail = errData.error || JSON.stringify(errData);
+                } catch (_) {
+                    const text = await resp.text();
+                    detail = text.substring(0, 500);
+                }
+                console.error("[AI] Upload HTTP", resp.status, detail);
+                alert("上传失败 (HTTP " + resp.status + ")\n" + (detail || "未知错误"));
+                return;
+            }
             const data = await resp.json();
             if (data.success) {
                 this.state.attachments = [
@@ -109,7 +123,7 @@ export class AiChatAction extends Component {
             }
         } catch (e) {
             console.error("[AI] Upload failed:", e);
-            alert("上传失败，请检查网络");
+            alert("上传失败，请检查网络\n" + e.message);
         }
     }
 
diff --git a/yuthon_ai_agent/static/src/js/ai_floating.js b/yuthon_ai_agent/static/src/js/ai_floating.js
index 219163822..bcc8d269e 100644
--- a/yuthon_ai_agent/static/src/js/ai_floating.js
+++ b/yuthon_ai_agent/static/src/js/ai_floating.js
@@ -93,7 +93,22 @@ async function uploadFile(file) {
         const resp = await fetch("/ai/attachment/upload", {
             method: "POST",
             body: formData,
+            credentials: "same-origin",
         });
+        if (!resp.ok) {
+            // 服务器返回错误状态码，尝试读取错误详情
+            let detail = "";
+            try {
+                const errData = await resp.json();
+                detail = errData.error || JSON.stringify(errData);
+            } catch (_) {
+                const text = await resp.text();
+                detail = text.substring(0, 500);
+            }
+            console.error("[AI] Upload HTTP", resp.status, detail);
+            alert("上传失败 (HTTP " + resp.status + ")\n" + (detail || "未知错误"));
+            return;
+        }
         const data = await resp.json();
         if (data.success) {
             pendingAttachments.push({
@@ -108,7 +123,7 @@ async function uploadFile(file) {
         }
     } catch (e) {
         console.error("[AI] Upload failed:", e);
-        alert("上传失败，请检查网络");
+        alert("上传失败，请检查网络\n" + e.message);
     }
 }