diff --git a/unraid_mcp/tools/keys.py b/unraid_mcp/tools/keys.py
index a761aa5..4b62105 100644
--- a/unraid_mcp/tools/keys.py
+++ b/unraid_mcp/tools/keys.py
@@ -116,11 +116,7 @@ def register_keys_tool(mcp: FastMCP) -> None:
                 data = await make_graphql_request(MUTATIONS["create"], {"input": input_data})
                 created_key = (data.get("apiKey") or {}).get("create")
                 if not created_key:
-                    return {
-                        "success": False,
-                        "key": {},
-                        "message": "API key creation failed: no data returned from server",
-                    }
+                    raise ToolError("Failed to create API key: no data returned from server")
                 return {"success": True, "key": created_key}
 
             if action == "update":
@@ -134,11 +130,7 @@ def register_keys_tool(mcp: FastMCP) -> None:
                 data = await make_graphql_request(MUTATIONS["update"], {"input": input_data})
                 updated_key = (data.get("apiKey") or {}).get("update")
                 if not updated_key:
-                    return {
-                        "success": False,
-                        "key": {},
-                        "message": "API key update failed: no data returned from server",
-                    }
+                    raise ToolError("Failed to update API key: no data returned from server")
                 return {"success": True, "key": updated_key}
 
             if action == "delete":
diff --git a/unraid_mcp/tools/notifications.py b/unraid_mcp/tools/notifications.py
index 16fdab9..e4f4790 100644
--- a/unraid_mcp/tools/notifications.py
+++ b/unraid_mcp/tools/notifications.py
@@ -307,6 +307,14 @@ def register_notifications_tool(mcp: FastMCP) -> None:
                         f"importance must be one of: {', '.join(sorted(_VALID_IMPORTANCE))}. "
                         f"Got: '{importance}'"
                     )
+                if len(title) > 200:
+                    raise ToolError(f"title must be at most 200 characters (got {len(title)})")
+                if len(subject) > 500:
+                    raise ToolError(f"subject must be at most 500 characters (got {len(subject)})")
+                if len(description) > 2000:
+                    raise ToolError(
+                        f"description must be at most 2000 characters (got {len(description)})"
+                    )
                 input_data = {
                     "title": title,
                     "subject": subject,