# OpenAI opens Codex agent harness to all developers

> OpenAI launched the Agents API in public beta on 10 September 2026.

*The Agents API packages sessions, subagents and hosted sandboxes behind one call, with no extra fee on top of tokens.*

By Behzad Hosseini · FeaturedDaily
Canonical: https://featureddaily.com/news/openai-opens-codex-agent-harness-to-all-developers

**What happened:** OpenAI launched the Agents API in public beta at 8am Pacific on 10 September 2026, the same morning it released GPT-Live-1 and ChatGPT for Financial Services.

**The details:** The API exposes the harness that already powers Codex and ChatGPT for Work: sessions, orchestration, automatic context compaction, tool search, subagents and recovery. One call sets the task, model, tools and environment. Four building blocks make it up: an Agent, an optional sandbox Environment, a durable Session, and streamed events.

**Who's affected:** It's open to all API developers, not just enterprise customers. Agents can run for hours or days, with sandboxes hosted on OpenAI's own infrastructure, self-hosted in a customer's cloud, or run via partners including Cloudflare, DigitalOcean, Oracle and Vercel. OpenAI always runs the harness itself.

**The numbers:** OpenAI said: "There are no additional fees for using the Agents API." Customers pay for model tokens, tools, and OpenAI-hosted container time only.

**The catch:** Data storage is US-only for now, and Zero Data Retention isn't supported yet.

**Who's using it:** Early customers named include Ciridae, Long Lake, WithCoverage, SafetyKit, Dwelly, Hypha, deepsense.ai and Nash.ai.

**Why it matters:** The scaffolding around a model increasingly determines what an agent can actually do. By productising its own harness, OpenAI is competing directly with Anthropic's Claude agent tooling for developers building long-running, tool-using agents.

**What's next:** As a public beta, the API is likely to expand in coverage, including eventual support for data retention controls beyond the current US-only storage limit. [OpenAI's announcement](https://www.marktechpost.com/2026/09/10/openai-launches-the-agents-api-in-public-beta-putting-the-codex-harness-behind-one-api-call/) describes the Agents API as "fully managed by OpenAI."

## Key takeaways

- Same Codex/ChatGPT for Work harness now open to all API developers
- No added fee; customers pay only tokens, tools, container time
- US-only data storage for now; no Zero Data Retention support

## Sources

- [OpenAI Launches the Agents API in Public Beta, Putting the Codex Harness Behind One API Call](https://www.marktechpost.com/2026/09/10/openai-launches-the-agents-api-in-public-beta-putting-the-codex-harness-behind-one-api-call/) — MarkTechPost, 2026-09-10