Can open-source prompt-injection detectors catch realistic AI agent attacks? 🎯 TL;DR I ran 10 open-source detectors against 629 real AgentDojo injection attacks, each buried inside ordinary tool output — the way an agent firewall actually sees them. None catches most attacks without also blocking normal traffic. 🥇 Best trade-off: 51% caught at 2% false positives 🔴 Meta's Prompt Guard 2: 1% caught 🚫 Two detectors flag 98% of safe tool outputs too And they fail in three different ways 👇 📊 Le...