Architecture Fitness Tests: Why Your Claude Code Needs Guardrails

As AI-assisted code generation tools like Claude Code become integral to development workflows, they risk violating architectural constraints that exist primarily in developers' minds. This article introduces architecture fitness tests—lightweight, AST-based static analysis that runs in milliseconds—as a practical safeguard against violations with real performance consequences. For teams using AI assistants on complex systems, this approach transforms architecture from informal guidelines into testable constraints, catching violations before they compound into system-wide degradation.