zero cost failed requests 3

https://weekly-wiki.win/index.php/Understanding_Glow_API_Pricing:_What_Developers_Should_Know_About_Marketplace_Routing_and_Model_Costs

You set up error tracking expecting to catch issues, but failed requests costing you nothing can still clutter logs and waste your time. When errors happen but don't incur extra fees, it's easy to ignore them—yet they might hide real problems in your system. Monitoring zero cost failed requests helps you distinguish minor glitches from critical failures without hurting your budget.