Why Documentation Should Be Treated as Part of Software Architecture

A software engineering perspective argues that documentation is not a post-development task but a core component of system architecture, on par with code itself. Undocumented design decisions — such as why a soft delete was chosen over a hard delete, or why a specific retry strategy was adopted — represent hidden constraints that future developers can unknowingly violate. Writing design documents before or during implementation, rather than after, forces engineers to surface flawed assumptions early, before costly code investment makes it harder to challenge an approach. Architecture Decision Records (ADRs) are highlighted as a practical tool for capturing the reasoning behind decisions, helping future engineers understand context that no compiler or code review can convey. The article concludes that treating documentation as optional leads to system decay even when all tests pass, because correctness of logic and correctness of intent are two entirely different things.