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 81e78b8e2..3fc860609 100644
--- a/yuthon_ai_agent/static/src/js/ai_chat_action.js
+++ b/yuthon_ai_agent/static/src/js/ai_chat_action.js
@@ -95,21 +95,23 @@ export class AiChatAction extends Component {
                 body: formData,
                 credentials: "same-origin",
             });
+            // 先读 text，再尝试解析 JSON（避免 body stream already read）
+            const text = await resp.text();
+            let data;
+            try {
+                data = JSON.parse(text);
+            } catch (_) {
+                data = null;
+            }
+
             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);
-                }
+                let detail = (data && data.error) || text.substring(0, 300);
                 console.error("[AI] Upload HTTP", resp.status, detail);
-                alert("上传失败 (HTTP " + resp.status + ")\n" + (detail || "未知错误"));
+                alert("上传失败 (HTTP " + resp.status + ")\n" + detail);
                 return;
             }
-            const data = await resp.json();
-            if (data.success) {
+
+            if (data && data.success) {
                 this.state.attachments = [
                     ...this.state.attachments,
                     {
@@ -119,7 +121,7 @@ export class AiChatAction extends Component {
                     },
                 ];
             } else {
-                alert(data.error || "上传失败");
+                alert((data && data.error) || "上传失败");
             }
         } catch (e) {
             console.error("[AI] Upload failed:", e);
diff --git a/yuthon_ai_agent/static/src/js/ai_floating.js b/yuthon_ai_agent/static/src/js/ai_floating.js
index bcc8d269e..d5ab1c833 100644
--- a/yuthon_ai_agent/static/src/js/ai_floating.js
+++ b/yuthon_ai_agent/static/src/js/ai_floating.js
@@ -95,22 +95,23 @@ async function uploadFile(file) {
             body: formData,
             credentials: "same-origin",
         });
+        // 先读 text，再尝试解析 JSON（避免 body stream already read）
+        const text = await resp.text();
+        let data;
+        try {
+            data = JSON.parse(text);
+        } catch (_) {
+            data = null;
+        }
+
         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);
-            }
+            let detail = (data && data.error) || text.substring(0, 300);
             console.error("[AI] Upload HTTP", resp.status, detail);
-            alert("上传失败 (HTTP " + resp.status + ")\n" + (detail || "未知错误"));
+            alert("上传失败 (HTTP " + resp.status + ")\n" + detail);
             return;
         }
-        const data = await resp.json();
-        if (data.success) {
+
+        if (data && data.success) {
             pendingAttachments.push({
                 attachment_id: data.attachment_id,
                 filename: data.filename,
@@ -119,7 +120,7 @@ async function uploadFile(file) {
             });
             renderAttachmentPreview();
         } else {
-            alert(data.error || "上传失败");
+            alert((data && data.error) || "上传失败");
         }
     } catch (e) {
         console.error("[AI] Upload failed:", e);