What is Petri (Parallel Exploration Tool for Risky Interactions)?

Petri is an open-source alignment auditing tool that runs an automated auditor model through many simulated interactions with a target model in parallel, each seeded from a short natural-language instruction describing a scenario to probe. A judge model then scores the resulting transcripts along dimensions such as deception, sycophancy, and inappropriate use of tools, turning open-ended behavioral exploration into ranked transcripts a human can review.