A persona file is a configuration or instruction file that defines how an AI agent presents itself, what style it uses, and how it should respond to prompts. In practice, it can act like the agent’s identity layer: it may set tone, role, boundaries, and behavior rules separate from the application’s source code.
This matters in cyber security because changing a persona file can alter an agent’s output or tool use without modifying binaries. Attackers may abuse that by overwriting the file after installation to redirect responses, weaken guardrails, or influence operator workflows. Defenders should treat persona files like sensitive configuration: restrict write access, verify integrity, monitor for unexpected edits, and alert on sudden changes to agent identity files. In AI-driven systems, a small text file can become a high-impact control surface.