AI coding agents are useful because they can make changes quickly. That same strength creates a review problem.
In a typical loop, an agent edits code, runs tests, reads failures, patches the implementation, and repeats. The loop may finish with clean tests and a reasonable diff. But somewhere along the way, a small behavior can change: a timeout becomes longer, an optional field becomes required, a retry policy becomes more forgiving, or an API starts accepting a state that used to be rejected.
None of those changes has to look obviously wrong in isolation. The issue is that the project’s behavior has moved, while the review surface still looks like a normal refactor.
That is the problem Truthmark is designed to help with. It gives an AI-assisted codebase a fact layer: human-readable, Git-reviewable Markdown files that describe what the project believes to be true. Agents can still write code quickly, but before they hand work back, they have to reconcile the code changes against the repository’s maintained truth.
For loop engineering, that is the useful part. Truthmark is not just a documentation tool. It is a way to make product and engineering drift easier to observe.
