Agents
OpenAI opens the Codex harness as a managed Agents API in public beta, with hosted sandboxes and automatic compaction
OpenAI launched the Agents API on 2026-09-10 in public beta for all developers. It is built on four primitives: Agent, an optional sandbox Environment, a durable Session and streamed events. Sandboxes can be OpenAI-hosted, self-hosted through `codex exec-server`, or run on nine partners (Blaxel, Cloudflare, Daytona, DigitalOcean, E2B, Modal, Oracle, Runloop, Vercel). Subagents get their own context, compaction is automatic, and billing covers only tokens, tools and container time. Data residency is US-only and Zero Data Retention is not supported, which rules out regulated workloads for now. Builders who hand-roll compaction and sandbox orchestration on the Responses API can now hand both to OpenAI.
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