---
title: "Hallucination"
canonical: https://replypen.com/glossary/hallucination
description: "An AI hallucination is a confident statement from an AI model that is false or made up: a policy that does not exist, a wrong price, an invented feature or a link that leads nowhere."
question: "What is an AI hallucination?"
author: "ReplyPen team"
published: 2026-09-30
operator: ProBackup BV (Hasselt, Belgium)
---

# What is an AI hallucination?

An AI hallucination is a confident statement from an AI model that is false or made up: a policy that does not exist, a wrong price, an invented feature or a link that leads nowhere. It happens because language models write what sounds plausible, and plausible is not the same as true.

The word is borrowed loosely from psychology. The model is not seeing things; it is filling a gap in
what it knows with text that fits the pattern of a good answer. Hallucinations are most likely when
the question needs a specific fact the model was never given.

## Why it matters

In customer email a hallucination is a promise your business did not make. "Yes, we offer free
returns within 60 days" is a pleasant sentence and, if your policy says 30, a problem you now have
to walk back. Because the text reads well, the error is easy to miss when you skim.

Three things reduce the risk: [grounding](https://replypen.com/glossary/grounding.md) the answer in your own sources,
showing which source each fact came from, and keeping a person between the draft and the customer
([human in the loop](https://replypen.com/glossary/human-in-the-loop.md)).

## An example

A customer asks for a discount code for students. No such discount exists, but a model without
access to your pricing writes a friendly reply with a code that looks real.

How to catch this before sending: [checking an AI-written answer](https://replypen.com/blog/check-ai-written-answer-before-sending.md).

## Related

- [Grounding](https://replypen.com/glossary/grounding.md): Grounding means an AI system bases its answer on specific source material, such as your help articles, website pages, past replies or records, instead of on what it absorbed during training.
- [Human in the loop](https://replypen.com/glossary/human-in-the-loop.md): Human in the loop means a person reviews and approves what an AI system produces before it takes effect.
- [Check note](https://replypen.com/glossary/check-note.md): A Check note is the short internal note ReplyPen places with each Draft, listing what it relied on: the help articles, website pages and past emails behind the reply.