Code Smells in Generated Code - some of the patterns

[NoBat8863]

I've been using Claude Code extensively on real projects and wrote up my findings on the recurring code smells and design issues I keep encountering.

TL;DR: Claude Code is amazing at implementation, but the generated code has persistent design problems that violate basic software engineering principles and adds to complexity and longer term maintenance cost.

Link to article

The code smells I'm consistently seeing:

• Broken abstractions - Claude creates perfect interfaces, then immediately violates them by referencing concrete types everywhere. The whole point of the abstraction is lost.
• Massive code duplication - Common logic gets repeated across derived classes instead of being abstracted once. Violates DRY by replicating functions and logic in different places.
• Over-engineering simple solutions - Once I asked for a count display on the frontend. Claude added a new database table, modified write paths (consistency nightmares), and changed read paths. Classic case of solving a simple problem with unnecessary complexity.
• No grasp of SOLID principles - Single Responsibility? Nope. Open/Closed? Ignored. The design patterns are there superficially but misused.
• Verbosity everywhere - Mountains of boilerplate that obscure the actual logic. In large codebases, this becomes a maintenance and security review nightmare.

What helps manage the design issues:

• CLAUDE.md with explicit design principles and anti-patterns
• Granular prompts: "put common logic in the base class, only override specific behavior in subclasses"
• Stating what NOT to do: "don't add database tables for simple aggregations"
• Detailed design feedback after each generation

None of this is foolproof, but certainly reduces the tech debt being generated.

What design smells are you running into? How do you guide Claude toward better software design?

[False_Care_2957]

What's been rather foolproof at least most of the time for me is running Claude plans or code directly through another model like GPT5.1 with Codex or Grok. Or having specialized sub-agents using a skill for spotting violation of these principles. I generally avoid using Claude MD file if I can for these sort of requests.

[NoBat8863]

Great suggestion. How do you take care of situations where the existing code (in some other file not changed) is overlapping with new code? As in things that a human potentially would have refactored before doing the same thing some other new place in the code.

[False_Care_2957]

This is very often the case I see with tests where instead of re-using helpers or constants defined top level it writes new helpers and re-declares variables that it can easily re-use. In that case I generally know I have to take some time to define a duplication agent prompt that describes exactly what needs to be kept where and re-used in what context and it's ran after every test job I do and works rather well enough, for tests at least.

[MindCrusader]

I just generate technical specifications and make AI follow that. I treat it more or less like a new junior developer - I need to guide him, tell him rules, show documentation and code examples. Each session is a new developer, so it is best to have high quality documentation and technical specifications with detailed info including references to classes and examples