diff --git a/backend/app/api/design_generator.py b/backend/app/api/design_generator.py
index e8304e4..698d4fa 100644
--- a/backend/app/api/design_generator.py
+++ b/backend/app/api/design_generator.py
@@ -126,6 +126,8 @@ Square format, clean edges for die-cut sticker."""
             status_code=504,
             detail="AI generation timed out"
         )
+    except HTTPException:
+        raise
     except Exception as e:
         raise HTTPException(
             status_code=502,
diff --git a/frontend/app/design/page.tsx b/frontend/app/design/page.tsx
index b74d420..8ada5d0 100644
--- a/frontend/app/design/page.tsx
+++ b/frontend/app/design/page.tsx
@@ -54,8 +54,15 @@ export default function DesignPage() {
       });
 
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Failed to generate design");
+        let message = "Failed to generate design";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
 
       const design = await response.json();
@@ -82,8 +89,15 @@ export default function DesignPage() {
       );
 
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Failed to activate design");
+        let message = "Failed to activate design";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
 
       setGeneratedDesign({ ...generatedDesign, status: "active" });
@@ -106,8 +120,15 @@ export default function DesignPage() {
       );
 
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Failed to delete design");
+        let message = "Failed to delete design";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
 
       setGeneratedDesign(null);
diff --git a/frontend/app/upload/page.tsx b/frontend/app/upload/page.tsx
index 952fd2e..22314d3 100644
--- a/frontend/app/upload/page.tsx
+++ b/frontend/app/upload/page.tsx
@@ -103,8 +103,15 @@ export default function UploadPage() {
       });
 
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Upload failed");
+        let message = "Upload failed";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
 
       const design = await response.json();
@@ -127,8 +134,15 @@ export default function UploadPage() {
         { method: "POST" }
       );
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Failed to activate design");
+        let message = "Failed to activate design";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
       setUploadedDesign({ ...uploadedDesign, status: "active" });
     } catch (err) {
@@ -146,8 +160,15 @@ export default function UploadPage() {
         { method: "DELETE" }
       );
       if (!response.ok) {
-        const data = await response.json();
-        throw new Error(data.detail || "Failed to delete design");
+        let message = "Failed to delete design";
+        try {
+          const data = await response.json();
+          message = data.detail || message;
+        } catch {
+          const text = await response.text();
+          message = text || `Server error (${response.status})`;
+        }
+        throw new Error(message);
       }
       resetForm();
     } catch (err) {