OpenAI acquires Promptfoo to stress-test AI agents before bad actors do

OpenAI is acquiring Promptfoo, a San Francisco-based AI security startup, in a move that signals how seriously the company is taking enterprise trust as it pushes deeper into agentic AI. The deal brings Promptfoo’s red-teaming and vulnerability-testing technology directly into OpenAI Frontier—its platform for deploying AI agents in corporate environments. Terms were not disclosed.

The acquisition is less about adding a new product and more about fixing a structural gap. Frontier is built around the idea of AI agents—autonomous software that can browse, write, execute code, and manage data on a user’s behalf.