A context file is documentation that the build never reads. Nothing fails when it goes stale. The paper on outdated code element references describes exactly this failure mode: documentation loses sync "silently", with no crashes and no error messages to signal the drift Detecting Outdated Code Element References in Software Repository Documentation. The same paper reports that up-to-dateness problems account for 39% of documentation content issues and that 82.3% of analyzed projects were outdated at least once during their history Detecting Outdated Code Element References in Software Repository Documentation.
Inherited repos are the worst case. The people who wrote the README, the CONTRIBUTING guide and the agent instructions are gone or busy, and the files still describe a world that no longer exists. Meanwhile the cost is real: a study of repository level context files such as AGENTS.md found that context files tended to reduce task success rates compared with providing no repository context, while increasing inference cost by over 20% Evaluating AGENTS.md: Are Repository-Level Context Files Effective?. That study also found human written context files showed marginal improvements over no context on its own benchmark, and concluded that human written files should describe only minimal requirements Evaluating AGENTS.md: Are Repository-Level Context Files Effective?.
The practical reading: stale context files are not neutral. They are actively read by agents and by new hires, they consume tokens on every call, and they steer behavior in the wrong direction. The audit exists to find and cut the parts that mislead.
One framing that helps: a context file should be a fact layer, not a tutorial. The argument for deterministic facts about the repository, indexed and checked, over prose that assumes the reader shares the author's memory, is made at length in Repository Context Should Be a Fact Layer. Your audit is the first pass at converting inherited prose into facts you can verify.



