The vibe coding question is interesting but I think the real risk for projects like this isn't how the code was written — it's test coverage. A LocalStack replacement lives or dies by API compatibility. If the S3 presigned URL behavior differs slightly, your integration tests pass locally but break in prod.

What I'd want to see before using this: a compatibility matrix showing which API operations are covered, ideally verified against the official AWS SDK test suites for each service.