Documenting legacy codebases REQUIRED BACKGROUND: the skill (hard rules, kind classification, truth rules, style). Overview A legacy codebase has one reliable witness: the code at HEAD. Everything else that speaks about it (names, comments, old documents, diagrams, the memory of whoever is left) is testimony. Core principle: describe how the system works and what to look out for, verified against the code; the code stays the authority on how it is implemented. The deliverable is a docs tree the next engineer trusts and the next refactor leaves untouched: only changed behavior or a new feature…