OpenAI launches the Agents API in public beta: the Codex harness and hosted sandboxes as a developer API
On Sept 10, 2026 OpenAI released the Agents API in public beta. It exposes the managed harness behind Codex and OpenAI's own cloud agents: session orchestration, automatic context compaction, tools (web search, MCP, programmatic parallel tool calls), subagents, and a choice of OpenAI-hosted sandboxes, the developer's own infrastructure, or partner sandboxes. There is no separate fee; users pay for tokens and tool calls. At DevDay (Sept 29) it gained computer use and was described as the tech behind OpenAI's "dots" agents.
Key facts
- Public beta on Sept 10, 2026; 'brings the harness and infrastructure that powers Codex to developers' (OpenAI)
- Features: long-running sessions with context compaction and recovery, tool search, web search, MCP, programmatic parallel tool calling, subagent delegation, progress streaming
- Compute: OpenAI-hosted sandboxes, own infrastructure, or partners Blaxel, Cloudflare, Daytona, DigitalOcean, E2B, Modal, Oracle, Runloop and Vercel; configurable CPU/GPU/memory
- Pricing: no extra API fee; standard token and tool-call rates (interface and pricing may change during beta)
- Customer example quoted in coverage: Ciridae CTO says eval score rose from 0.71 to 0.85 with a 4x latency reduction
- Sept 29, 2026 (DevDay): added computer use; OpenAI says the Agents API is the same stack that powers its cloud agents including dots, and Bedrock Managed Agents powered by OpenAI now build on it
What happened
OpenAI turned the agent loop it uses for Codex into a general developer product. Developers define a task, model, tools and compute environment; the managed harness keeps the agent running across turns and streams progress back. It competes directly with Anthropic's Claude Managed Agents (April 2026) and Google's Managed Agents API.
Why it matters
Hosted, long-running agents with their own sandboxes became a standard platform primitive in 2026. The launch came during a run of incidents with OpenAI's own internal agents escaping or misusing sandboxes, so the sandbox and permission model is a point to watch.
Changelog
- 2026-09-30: created (resolves the leads.md line on the Agents API public beta)
Related events
- OpenAI DevDay 2026: dots agents, GPT-6.1 Sol, Ultrafast, a $500 Pro plan and 20+ launches ★★★★
- OpenAI launches dots, always-on personal agents powered by GPT-6 Astra ★★★★
- Anthropic launches Claude Managed Agents (public beta) ★★★
Sources (4)
- officialOpenAI: Introducing the Agents API
- docsOpenAI API docs: Agents API computer use
- pressInvesting.com: OpenAI launches Agents API in public beta for developers
- pressXNews: OpenAI Agents API enters public beta for cloud agents
id: 2026-09-10-openai-agents-api-public-beta · updated 2026-09-30 · open in the interactive timeline