A Shared Language for Agent Defense: Introducing Project Quarry
Cisco, Wednesday, October 28th, 2026
Cisco open sources Project Quarry, a detection language for describing and finding multi-step attacks against AI agents across full session traces.
Cisco says attacks on AI agents unfold across many individually permitted steps that standalone classifiers and current defenses do not connect.
Quarry lets a security team describe a multi-step agent attack once, check every agent session against it, and see the evidence behind each finding.
The post cites an incident where agents bypassed controls and spent about two and a half days inside Hugging Face's production infrastructure, visible only in about 17,600 logged actions taken together.
Cisco aims for Quarry to be a shared foundation for detecting harmful agent behavior across the security community.