Apps written in an exceptions language (Java, JavaScript, PHP, etc..) are really annoying to monitor as everything that isn't the happy path triggers an 'error'/'fatal' log/metric.

Yes, you can technically work around it with (near) Go-level error verbosity (try/catches everywhere on every call) but I've never seen a team actually do that.

Modern languages that don't throw exceptions for every error like Rust, Go, and Zig make much more sane telemetry reports in my experience.

On this note, a login failure is not an error, it's a warning because there is no action to take. It's an expected outcome. Errors should be actionable. WARN should be for things that in aggregate (like login failures) point to an issue.

If there are new bugs every day that need fixed is the AI really good enough to know the fix from just an error?