OpenAI is acquiring Promptfoo, a security platform used by over a quarter of Fortune 500 companies to test AI vulnerabilities. The deal means Promptfoo’s tech — which catches things like prompt injections, jailbreaks, and data leaks — will be baked directly into OpenAI Frontier, the company’s enterprise platform for building AI coworkers. The idea is to make security testing a seamless part of development, not an afterthought. Promptfoo’s popular open-source tools will stay alive, but the bigger play is integrating enterprise-grade evaluation, red-teaming, and compliance features into Frontier. Why it matters: This signals that as AI agents get more autonomy and access to real systems, the industry is shifting from ‘move fast and break things’ to ‘move fast but prove it’s safe’ — and acquisition is faster than building from scratch.