Hardin Filter checks AI answers from ChatGPT, Claude, Gemini, and Copilot for what actually matters: fabricated citations, references that don't exist, numbers that don't add up, contradictions, leaked data, and outdated info presented as current. Every check produces a signed, verifiable receipt (via our partners at TBN Protocol) — proof of what was checked, not just a green tick. Chrome extension, VS Code extension, or paste-in web tool. Free, no account needed.