Google ADK's Multi-Layer Defense Against Indirect Prompt Injection in AI Agents

Indirect prompt injection—where malicious instructions arrive through tool responses rather than user input—is now the #1 risk for LLM applications according to OWASP, yet traditional content filters miss such context-dependent manipulation. Google's Agent Development Kit proposes framework-level security with five defense layers (identity control, guardrails, and multi-layer screening) rather than bolt-on filters, addressing how agents fundamentally break conventional assumptions about controlled inputs. This architectural approach reflects industry maturation as AI systems become production-critical infrastructure.