The Agents API gives applications access to the Codex harness through an OpenAI-managed API. OpenAI manages sessions, orchestration, context compaction, and recovery, while your application provides tools and selects its execution environment.

Agents can operate in a sandbox to execute code, edit files, connect to MCP servers, and produce artifacts. Model usage is billed at the selected model's API rates. OpenAI tools use standard rates, and OpenAI-hosted sandboxes use standard container rates.

The Agents API supports four main concepts: Agent (model, instructions, tools, MCP servers), Environment (optional sandbox or computer), Session (durable instance), and Events and items (inputs and outputs). You can start with an OpenAI-hosted sandbox in the quickstart, create a session, configure the agent, give it a task, and follow progress via streaming or webhooks.

Sessions retain state across turns, and you can delete sessions and artifacts when no longer needed. The API currently supports data residency only in the United States and does not support Zero Data Retention (ZDR). Choosing a self-hosted sandbox does not make the API ZDR-eligible.