How to prevent prompt injection attacks

Act as an application security engineer. Answer this question: “How do we threat-model prompt injection?”

Objective: threat-model direct and indirect prompt injection in an AI application.

First, ask up to five concise questions needed to tailor the analysis. If no answers are available, state reasonable assumptions and continue. Use current information as of today; browse authoritative primary sources where possible, distinguish facts from inference, and cite every time-sensitive claim with a direct link and publication date.

Cover: trust boundaries, untrusted content, tool permissions, data exfiltration, confused deputy risks, mitigations, tests, and residual risk.

Structure the response as:
1. Executive answer in five bullets
2. Current evidence and what has changed recently
3. Options with benefits, costs, risks, and prerequisites
4. Recommended approach with explicit assumptions
5. 30/60/90-day action plan with owners and measurable outcomes
6. Failure modes, warning signs, and mitigations
7. Decision checklist
8. Sources

Avoid hype, unsupported predictions, and generic advice. Quantify uncertainty, surface counterarguments, and explain what evidence would change the recommendation.