Lethal trifecta
The three agent abilities that together make data theft easy: access to private data, exposure to untrusted content, and a way to send information out. Coined by developer Simon Willison; the usual advice is to never give one agent all three.
“The inbox agent could read secrets, read strangers' emails, and send email. That's the lethal trifecta.”
See also
Part of the Extended list
Lethal trifecta is on the Extended list: builder jargon, industry terms, and newer slang for when you want to go further. It entered common use around 2025.