diff --git a/autogpt_platform/backend/backend/api/features/workspace/routes.py b/autogpt_platform/backend/backend/api/features/workspace/routes.py
index 2102b1f102..b96e953491 100644
--- a/autogpt_platform/backend/backend/api/features/workspace/routes.py
+++ b/autogpt_platform/backend/backend/api/features/workspace/routes.py
@@ -273,13 +273,16 @@ async def upload_file(
                 f"Failed to soft-delete over-quota file {workspace_file.id} "
                 f"in workspace {workspace.id}: {e}"
             )
+        from backend.util.workspace import _format_bytes
+
         raise fastapi.HTTPException(
             status_code=413,
-            detail={
-                "message": "Storage limit exceeded (concurrent upload)",
-                "used_bytes": new_total,
-                "limit_bytes": storage_limit_bytes,
-            },
+            detail=(
+                f"Storage limit exceeded. "
+                f"You've used {_format_bytes(new_total)} of your "
+                f"{_format_bytes(storage_limit_bytes)} quota. "
+                f"Delete some files or upgrade your plan for more storage."
+            ),
         )
 
     return UploadFileResponse(
diff --git a/autogpt_platform/backend/backend/util/workspace.py b/autogpt_platform/backend/backend/util/workspace.py
index a57469baa0..0cefe770e4 100644
--- a/autogpt_platform/backend/backend/util/workspace.py
+++ b/autogpt_platform/backend/backend/util/workspace.py
@@ -20,6 +20,17 @@ from backend.util.settings import Config
 from backend.util.virus_scanner import scan_content_safe
 from backend.util.workspace_storage import compute_file_checksum, get_workspace_storage
 
+
+def _format_bytes(n: int) -> str:
+    """Format bytes as a human-readable string (e.g. 250 MB, 1.0 GB)."""
+    if n < 1024:
+        return f"{n} B"
+    if n < 1024 * 1024:
+        return f"{n / 1024:.0f} KB"
+    if n < 1024 * 1024 * 1024:
+        return f"{n / (1024 * 1024):.0f} MB"
+    return f"{n / (1024 * 1024 * 1024):.1f} GB"
+
 logger = logging.getLogger(__name__)
 
 
@@ -211,10 +222,11 @@ class WorkspaceManager:
 
         projected_usage = current_usage + len(content)
         if storage_limit > 0 and projected_usage > storage_limit:
-            used_pct = (current_usage / storage_limit) * 100
             raise ValueError(
-                f"Storage limit exceeded: {current_usage:,} bytes used "
-                f"of {storage_limit:,} bytes ({used_pct:.1f}%)"
+                f"Storage limit exceeded. "
+                f"You've used {_format_bytes(current_usage)} of your "
+                f"{_format_bytes(storage_limit)} quota. "
+                f"Delete some files or upgrade your plan for more storage."
             )
         if storage_limit > 0 and projected_usage / storage_limit >= 0.8:
             logger.warning(
diff --git a/autogpt_platform/frontend/src/lib/direct-upload.ts b/autogpt_platform/frontend/src/lib/direct-upload.ts
index 22fd79f4a4..c6050fc84a 100644
--- a/autogpt_platform/frontend/src/lib/direct-upload.ts
+++ b/autogpt_platform/frontend/src/lib/direct-upload.ts
@@ -40,8 +40,18 @@ export async function uploadFileDirect(
   });
 
   if (!res.ok) {
-    const detail = await res.text().catch(() => res.statusText);
-    throw new Error(`Upload failed (${res.status}): ${detail}`);
+    let message: string;
+    try {
+      const body = await res.json();
+      // Backend returns { detail: "..." } or { detail: { message: "..." } }
+      message =
+        typeof body.detail === "string"
+          ? body.detail
+          : (body.detail?.message ?? res.statusText);
+    } catch {
+      message = res.statusText;
+    }
+    throw new Error(message);
   }
 
   return res.json();