AI engineering glossary · Evals guardrails AI security
What is canary token?
Canary token: A unique, harmless marker planted in a prompt, document or system so that its appearance elsewhere signals a leak or breach. In AI apps a secret string in the system prompt shows that prompt leaking occurred if it shows up in an output.
Canary token: an example
A random string is placed in the hidden prompt, and a filter blocks any reply that contains it.
Related terms
More Evals guardrails AI security terms
- Chatbot Arena
- Citation checking
- Constitutional classifiers
- Content moderation
- Crescendo attack
- Cross-tenant leakage
- Data exfiltration
- Data masking
Where you learn it
Canary token is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.