When Claude invents facts (and how to stop it)

What you will be able to do

You will spot when Claude invents a discount, policy, or timeline because a slot was empty—and you will stop it with the same desk-check rules used for emails and quotes.

What “invents facts” looks like on a busy desk

You asked for a warmer follow-up. The draft offers ten percent off. You never ran a discount.

You asked for a late note. The draft promises “Friday morning.” You never approved a time.

You asked for a proposal polish. The draft adds a “complimentary inspection.” You do not give those away.

That pattern is hallucination: content not present in the grounded context, dressed as courtesy. Anthropic documents ways to reduce hallucinations by grounding and allowing “I don’t know.” Your shop version is [NEED] plus a human send.

Missing slots → invented business facts

| Empty slot | Common invention | | --- | --- | | Price | Discount or “standard package” | | Policy | Flexible cancel, free add-on | | Time | Soon, this week, priority slot | | Scope | Extra visit, free consult |

Fix the slot. Do not ask for a “more human” tone until the facts are right. Tone is not the bug — see better prompts and customer emails.

Desk-check rules (same as other Deeplathe notes)

Before anything customer-facing leaves:

1. Would you say this at the desk?
2. Is every price, time, and promise already approved?
3. Exactly one ask?
4. Did the model invent a policy, discount, or timeline?
5. Any [NEED] still blank? Fill or delete the line.

How to stop it upstream

• Job in one sentence
• Smallest fact list
• “Do not invent. Mark gaps [NEED].”
• Two passes (draft, tighten)
• Projects with standing “never invent price/policy” instructions
• No unsupervised send for refunds, medical, legal threats, or angry disputes

Try this job: break a bad draft on purpose

1. Ask Claude to “make this follow-up nicer” with no price and no ask.
2. Highlight every invented commitment.
3. Re-run with Job + Facts + [NEED].
4. Confirm the inventions are gone.
5. Save both drafts in a training folder labeled hallucination-examples.

Short close

Empty slots invent discounts—fill the facts, mark [NEED], and desk-check before you send.