OpenAI launches Agents API, exposing its Codex agent harness

OpenAI released a public beta of its Agents API, giving developers the same harness and infrastructure that runs Codex. Developers can run the agent's compute in an OpenAI-managed sandbox, their own infrastructure, or a partner sandbox.

Why it matters: This moves OpenAI from selling models to selling a full agent runtime, competing directly with frameworks and startups that provide agent orchestration and sandboxing. It's part of a broader shift where model providers are vertically integrating the 'harness' layer that turns raw model calls into working autonomous agents.