I absolutely have the hang of Claude and I still find that it can make those ridiculous mistakes, like replicating logic into a test rather than testing a function directly, talking to a local pg that was stale/ running, etc. I have a ton of skills and pre-written prompts for testing practices but, over longer contexts, it will forget and do these things, or get confused, etc.
You can minimize these problems with TLC but ultimately it just will keep fucking up.
My favorite is when you need to rebuild/restart outside of claude and it will "fix the bug" and argue with you about whether or not you actually rebuilt and restarted whatever it is you're working on. It would rather call you a liar than realize it didn't do anything.
this is a pretty annoying problem -- i just intentionally solve it by asking claude to always use the right build command after each batch of modifications, etc
"That's an old run, rebuild and the new version will work" lol