I inherited some vibe-coded scripts that dealt with AWS services like Bedrock and S3. These scripts needed create various AWS SDK clients. These clients needed to know which account/region to use.
Had this been well designed, there would have some function/module responsible for deciding what account/region to use. This decision point might be complex: it might consider things like environment variables, configuration files, and command line arguments. It might need to impose some precedence among these options. Whatever these details, the decision would be authoritative once made. The rest of the code base should have expected a clear decision and just do what was decided.
Instead, the coding assistant added optional account/region arguments in many submodules. These arguments were nullable. When left unspecified, "convenient" logic did its own environment lookups and similar. The result was many "works on my machine" failures because command-line arguments affected only certain portions of the program, environment variables others, config files still others.
This is grim stuff. It's a ton of code that should not exist, spreading the decision all over the code.
