OpenAI released the harness that powers Codex via API

On September 10, 2026, OpenAI launched the public beta of the Agents API — a managed service that provides via API the harness (orchestration layer) powering Codex and ChatGPT for Work.

Compiled by Sergey KostenchukPublished 2026-09-12Updated 2026-09-18

2026-09-12 Research OpenAI

🤖 OpenAI released the harness that powers Codex via API

On September 10, 2026, OpenAI launched the public beta of the Agents API — a managed service where an agent is created with a single call, including the model, tools, and environment. The service handles sessions, orchestration, context compression, and subagents, while in the sandbox the agent executes code and connects to MCP servers.

🌍 The agent orchestration layer is becoming a cloud service instead of a custom framework: compute can be kept in OpenAI's sandbox, self-hosted via codex exec-server, or with 9 partners — Blaxel, Cloudflare, Daytona, DigitalOcean, E2B, Modal, Oracle, Runloop, Vercel.

👤 Developers don't need to write the wrapper around the LLM: the beta is available now, with billing only for tokens. Limitations: data is stored only in the US, and Zero Data Retention is not supported.

Source 1: https://openai.com/index/introducing-the-agents-api/ Source 2: https://developers.openai.com/api/docs/guides/agents-api/overview

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