OpenAI announced on Wednesday that it is opening its Agents API, the core agent architecture powering its flagship programming assistant Codex and enterprise-grade ChatGPT, to external developers, effective immediately for public beta testing. The API aims to lower the engineering barrier for building long-running agents, allowing developers to access it without additional fees, paying only for actual token consumption and tool calls. Early customer data shows that the product has brought significant improvements in cost, efficiency, and reliability, such as a 60% reduction in per-case processing costs and an 86% decrease in agent response failure rates. OpenAI has also reached integration agreements with ecosystem partners such as Blaxel, Cloudflare, and Oracle to provide flexible deployment options.