Khoury College of Computer Sciences
CS 4550 / CS 5610 · Web Development · Fall 2026
OpenAI Agents API: Codex harness for cloud agents in public beta
- AI
- Course
Instructor-curated digest, not original reporting. Each post paraphrases a public article and links to the original source.
On September 10, 2026, OpenAI introduced the Agents API in public beta. It exposes the same harness and infrastructure that powers Codex so developers can create cloud agents through an API: specify the task, model, tools, and environment, then let OpenAI host and maintain the harness.
You choose where the agent runs — an OpenAI-hosted sandbox, your own infrastructure, or partner sandboxes (the post names providers including Blaxel, Cloudflare, Daytona, DigitalOcean, E2B, Modal, Oracle, Runloop, and Vercel). The harness covers long-session context compaction, tool search and programmatic tool calling (including MCP, custom functions, and web search), and optional multi-agent subagent delegation. The post says the API is powered by the open-source Codex harness, with no extra fee beyond tokens and tools used.
The hosted harness is another way to run an agent around the Next.js app you build in Chapter 1.
Read original: Introducing the Agents API — OpenAI
Related in the book: Chapter 1