Nyx – multi-turn, adaptive, offensive testing harness for AI agents

We built Nyx to solve a problem we kept hitting while building agents: AI agents break in ways traditional software doesn't. Logic bugs, reasoning failures, edge cases that manual testing and static benchmarks never explore.

Nyx is an autonomous testing harness that probes your AI agents to find failure modes before users do. It’s used to find logic bugs, instruction following failures, edge cases in agent behavior, and for red-team security testing (jailbreaks, prompt injection, tool hijacking)

Technical approach: * Pure blackbox (no special access needed - test like your users interact) * Multi-turn adaptive conversations * Multi-modal testing (voice, text, images, documents, browser interactions) * Massively parallel by default

Instead of spending time writing static evals for the key failure modes of your AI agents, point Nyx at any system and it autonomously discovers failure modes that matter. We typically find issues in under 10 minutes that manual audits take hours to surface.

This is early work and we know the methodology is still going to evolve. We would love nothing more than feedback from the community as we iterate on this.