Prompt-Injection Defense in Agent Pipelines

Defend agents that read untrusted content — web pages, tool outputs, user files, emails — from prompt injection, where attacker text hidden in that content hijacks the agent's behavior. Learn the trust-boundary mindset, treat all retrieved content as untrusted data rather than instructions, and stack defenses (least privilege, separation, allowlists, human gates, deterministic hooks) so a single injected instruction can't cause real damage.