We keep seeing the same pattern team ships an agent, agent works great in testing, agent gets prompt injected in production within the first week.
73% of production AI deployments showed prompt injection exposure in security audits last year. Most of them had zero defensive layers. Not weak layers zero.
So we wrote a practical guide covering the 7 things you should actually do in priority order
Day 1 (free, immediate)
- Harden your system prompt explicit deny lists, not vague "be safe" instructions. The article has bad vs. good examples
- Run adversarial testing fire real attacks at your agent and see what gets through
- Add pattern matching on input Aho-Corasick across 30+ injection signatures, sub-1ms, zero tokens
Week 1
4. Structural analysis rules entropy scoring, instruction density, URL/domain flagging
5. Tool call validation if your agent calls APIs, validate every argument before execution
6. Output scanning secret detection, exfiltration markers, concealment patterns
Week 2
7. Multi turn session tracking attacks split across messages where each one looks benign individually
The guide has code examples for each layer and explains what real attacks each one blocks.
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