RunSybil builds Sybil, an AI agent that continuously and autonomously performs penetration tests on live software — no source code access required. Sybil interacts with running systems the way a skilled attacker would: chaining vulnerabilities across web, APIs, cloud, and infrastructure to find real, exploitable flaws before adversaries do. Unlike traditional pentests (periodic, manual, expensive) or static scanners (noisy, code-dependent), Sybil runs continuously, triggering on every deployment and documenting confirmed exploits — not theoretical flags. The company claims 90% fewer false positives than standard scanners. Founded in 2023 by Ari Herbert-Voss (OpenAI's first security researcher) and Vlad Ionescu (former head of Meta's Red Team X), the team draws from OpenAI, Meta/Mandiant, Palantir, Cruise, and Trail of Bits. Customers today span high-growth tech startups (Cursor, Notion, Turbopuffer, Baseten, Thinking Machines Lab) and undisclosed large financial institutions and Fortune 500 companies. The business runs on a subscription model with custom enterprise pricing.