https://t0ul.com/tags/hallucination/Recent content in Hallucination on t0ulHugoen-usTue, 21 Apr 2026 00:00:00 +0000https://t0ul.com/blog/hallucinated-dates/Tue, 21 Apr 2026 00:00:00 +0000https://t0ul.com/blog/hallucinated-dates/<p><em>Part of my <a href="https://t0ul.com/blog/the-plan/">AI Security Engineering</a> series, a local email-to-calendar agent I build, then attack, then harden. If you have not set up the lab yet, start with <a href="https://t0ul.com/blog/setting-up-the-lab/">Set up your lab</a>. The lessons are <a href="https://github.com/t0ul/ai-security-engineering">on GitHub</a>, and the agent itself lives at <a href="https://github.com/t0ul/emaildrop">t0ul/emaildrop</a>.</em></p> <h2 id="a-date-that-was-never-there">A date that was never there</h2> <p>The last post caught data that was wrong in the email: a weekday that did not match its date, a borrowed time, a flipped negation. Every one of those was catchable because the email contradicted itself, and a deterministic check could see the contradiction. This post is about the error with no contradiction to find. The email simply does not say when an event is, and the model, asked for a date, makes one up.</p>