Prompt redaction means preserving the task while removing the real-world identifiers the model does not need — names, emails, IDs, payment data, medical details, or secrets.
The three redaction approaches
There are three practical ways to clean a prompt before submitting it to an AI tool:
Remove — delete the sensitive data entirely when the AI does not need it to complete the task. If you are asking for help drafting a reply to a complaint, the customer's account number is not necessary. Delete it.
Replace — substitute real identifiers with generic placeholders that preserve enough context for the model to help. Replace "Jan de Vries" with "the customer" or "Customer A". Replace real email addresses with example.com addresses.
Mask — preserve the structure while hiding the value. Replace "IBAN NL91ABNA0417164300" with "IBAN [MASKED]" when the structure matters but the real value does not.
Remove data when the task does not need it. Replace data when a realistic example helps the model answer. Mask data when context matters but the original value does not.
Examples by team
Support teams
Risky prompt: "Jan de Vries (jan@example.com, account #47291) called to complain about an overcharge of €47. Help me draft an apology."
Safer prompt: "A customer complained about an overcharge. Help me draft an apology that acknowledges the error and explains what happens next."
The account number, name, and email are not needed for the task. The model can help draft the apology without them.
HR teams
Risky prompt: "Here are Sarah Johnson's last three performance reviews. She earns €65,000 and has had two warnings. Help me write a summary for her annual review."
Safer prompt: "An employee has had a mixed performance history with two formal warnings. Help me write a constructive annual review summary that focuses on improvement areas."
Finance teams
Risky prompt: "Invoice from Acme Corp for €127,500 for project Falcon. Terms: net 30. Approve and draft a payment confirmation."
Safer prompt: "An invoice from a vendor for €127,500 has been approved. Draft a payment confirmation email."
Legal teams
Risky prompt: "This is from the acquisition file for TechCorp BV. The deal value is €4.2M. Summarize the key risk items."
Safer prompt: "This is a due diligence summary for a mid-size acquisition. Summarize the key risk items without client or company names."
Is anonymisation always enough?
No. Some combinations of context can still identify a person, so prompt redaction should be paired with data minimisation. Even with names removed, a prompt that includes role, department, salary range, and specific dates might still identify an individual in a small organization.
Frequently asked questions
Is anonymisation always enough? No. Some combinations of context can still identify a person, so prompt redaction should be paired with data minimisation.