LLM Prompt Injection & Guardrail Security (opens in new tab)

A recall reference built from working through a 7-layer prompt-injection challenge. Focus: how each defense layer works, where it breaks, and most importantly how to defend. The one idea underneath everything LLMs have no hard boundary between instructions and data. Everything in the context window — system prompt, user message, retrieved documents — is one stream of tokens the model interprets. Prompt injection exploits exactly this: attacker-controlled data gets read as instructions. You ca...