Simon Willison's 'Lethal Trifecta': three conditions that let attackers hijack AI agents
2C_ornot2C · x · 2026-11-08
Simon Willison warns anyone using AI agents (LLMs that call tools) about the "Lethal Trifecta": whenever a system combines access to private data, exposure to untrusted content, and the ability to communicate externally, an attacker can trick it into exfiltrating your data. The accompanying diagram visualizes the three overlapping conditions — a foundational risk framework for prompt injection in any agent application that wires LLMs to tools and data.
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