If you re building agents, this is worth knowing.Simon Willison (who coined the term prompt injection ) describes three capabilities that are individually fine but devastating together, the lethal trifecta includes:1. Access to private data (such as internal databases, emails, etc.)2. Exposure to untrusted content (like web pages and external text)3. The ability to exfiltrate data (a tool or a channel of sorts that reaches the outside world)Combine all three in one agent and you ve got a perfect storm: untrusted content can hijack the agent into reading private data and then persuade the agent to send it out.To teach the lethal trifecta, I built a Gandalf-style puzzle: 10 levels, each a real injection concept, with the full trifecta as the final level. It s free, there s no sign up and initially it s beginner-friendly.See if you can chain all three together and complete the trifecta!