AI Guard(Human Attestation) is a serverless GitHub App, running on Cloudflare Workers, that requires a human to sign off on a pull request before it can merge. When a PR opens, the app adds a Human Attestation check that starts out blocked. A person signs in with GitHub, passes a Cloudflare Turnstile challenge, and confirms a short statement. For example, "I confirm the code in this PR was written by a human" or "I have read and understood all agent-written code in this PR." The check then turns green and stays green for later pushes, since each PR needs only one attestation. PRs from human collaborators with write access skip the flow. Bot accounts never do. The Worker keeps no database: the state lives in the check run and in a comment the app posts on the PR.