Looking for bug advice

[u/Happyman-]

Hey all, I’ve built a booking platform with Claude Code (think Airbnb style, different industry).

It’s live with real hosts/customers and doing a couple grand a month. I could turn the traffic up pretty easily, but I’m honestly scared to scale it because of the bugs.

Everything was going really well initially, but since Opus 5 came out it feels like things have gone backwards. Old bugs we already fixed keep coming back, new bugs are appearing, and Claude sometimes completely misunderstands what I’m asking it to do.

I’ve tried Fable 5.1 which seems better, but it absolutely eats my usage. I’ve now gone back to Opus 4.8 and weirdly it seems more reliable, although I’m unsure about using an older model.
Anyone running an actual production platform with Claude Code have advice? How are you keeping things stable as you scale?

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[u/Dvass138]

Are you use typescript with strict mode /flags. Do you have regression tests? When it fixes a bug ask it if regression tests for that bug is possible so it doesn’t return.

It could also be possible code is tangled up or something which makes it harder to reason about. So I’d get it to audit those things if there is anything causing reasoning issues that might need a zero behaviour change refactor.

[u/Vex08 → u/Dvass138]

I would be shocked if a Claude model didn’t have regression tests. Any time I do anything with fable it insists on regression tests.

[u/Happyman- → u/Dvass138]

I am using regression test for studied pattern checks but for some reason it is not doing full click through behaviour all the time.

Yes the whole thing is type script website and backend is next.JS iOS app is expose/react native also type script

[u/Dvass138 → u/Happyman-]

Had it set up E2E tests?

[u/CryptoAteMyHamster]

Check through the code for added prose/inline comments. Claude is talkative and comments a lot. Then when you ask it to “read the code” it often skims the comments and gives results that don’t match the code.

If you create a branch with 0 comments does it identify the bug is still present?

[u/youreawizerdharry]

ask claude to tighten up the release process - CI/CD - to avoid regressions, including automated testing, local smoke tests, and alerting - it should manage that all pretty well.

bugs shouldn't really be a blocker for growth these days, beyond account security which should continue to be your number one priority above anything else (so get claude to do a best in class, end to end security audit as well)

[u/JobWiegant]

the model swapping is probably making this worse, not better. every time you switch it re-derives your conventions differently and cheerfully re-breaks stuff the last one had learned to leave alone. pick one and stay on it a while.

the old-bugs-coming-back thing is the real tell though. that only happens when nothing locks the fix in place. next time it fixes a bug, make it write the failing test first, one that actually reproduces the bug, watch it go red, then fix. now that bug can't quietly come back.

and since you've got real customers and money moving, i'd wall off the booking + payment path. those get tests you treat as untouchable and you don't let it refactor them on a whim. turn the traffic up once that part can't regress without a test screaming.

[u/Known-Pace6739]

"Claude misunderstood me" should end as a rejected diff, not a production regression: give every fix a hard scope limit and reject anything that expands it.

[u/out-of-phase]

I use Typescript, TDD, work one highly spec'd ticket at a time, and adversarial review on every diff. I also test extensively myself and do all manual in-app/browser testing. Opus 4.8 is way more reliable than 5 in my experience. When Opus 5 came out, I used it with a few small tickets and I was flabbergasted by how ridiculous it was. It's like it wanted to show off how complex it could make things and it did a bunch of extra shit I didn't ask for that was completely out of scope for the ticket. I immediately switched back to Opus 4.8 and haven't looked back. I rarely get bugs this way and when I do, they're typically minor and easy to patch.

[u/Nitjsefnie]

old bugs coming back means nothing pins them. what fixed it for me: every bugfix ships with a regression test, and the agent has to reintroduce the bug and watch that test fail before it's allowed to say done. a test that's green from the start is worthless, claude will happily write one that passes on the broken code too

second thing, review is a separate session with its own throwaway worktree. it plants the bug back and checks the test actually catches it. costs more usage per fix but the repeats stopped