Your agent reads untrusted content and can send data externally. How do you stop prompt-injection data exfiltration?
When an agent holds private data, reads untrusted text, and can talk to the outside, injected instructions can steal data. This 'lethal trifecta' is the defining agent vulnerability. The fix is architectural, not a better prompt.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
When an agent holds private data, reads untrusted text, and can talk to the outside, injected instructions can steal data. This 'lethal trifecta' is the defining agent vulnerability. The fix is architectural, not a better prompt.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
