OpenAI Makes Codex into an API: Agents API Goes Live, Hosting Sessions and Sandboxes Open to the Public
OpenAI officially launched the Agents API, encapsulating Codex harness into a managed REST interface. The core endpoint is POST /v1/agents/sessions, which requires the OpenAI-Beta header. OpenAI is responsible for sessions, orchestration, context compression, and recovery, while the application side provides tools and execution environments. The documentation outlines four core concepts and management capabilities: Agent (model + instructions + tools + MCP Server), Environment, etc.