Current outcome
OpenAI introduced the Agents API, a managed service powered by the Codex harness that lets developers build and launch cloud agents with orchestration, long-running sessions, and tool use. The API runs the Codex harness and handles the underlying agent infrastructure so teams can focus on what their agents do rather than on the runtime that keeps them alive. This moves agent deployment from self-hosted, DIY frameworks toward a managed runtime shipped by a major AI lab, which could standardize how long-running, tool-using agents are built and deployed across the ecosystem. It also raises competitive pressure on open-source agent frameworks and on cloud providers that offer their own agent runtimes, since developers now have a first-party option from OpenAI. According to OpenAI's API documentation, the Agents API includes automatic context compaction, multi-agent orchestration, programmatic tool calling, and support for MCP, with the Codex harness owning low-level session behavior such as thread resume, tool continuation, compaction, and app-server execution. It builds on the earlier Agents SDK and its evolution toward native sandbox execution and a model-native harness.
Progress timeline
1 material updates- #01
OpenAI Launches Agents API: Managed Cloud Agents on Codex Harness
OpenAI introduced the Agents API, a managed service powered by the Codex harness that lets developers build and launch cloud agents with orchestration, long-running sessions, and tool use. The API runs the Codex harness and handles the underlying agent infrastructure so teams can focus on what their agents do rather than on the runtime that keeps them alive. This moves agent deployment from self-hosted, DIY frameworks toward a managed runtime shipped by a major AI lab, which could standardize how long-running, tool-using agents are built and deployed across the ecosystem. It also raises competitive pressure on open-source agent frameworks and on cloud providers that offer their own agent runtimes, since developers now have a first-party option from OpenAI. According to OpenAI's API documentation, the Agents API includes automatic context compaction, multi-agent orchestration, programmatic tool calling, and support for MCP, with the Codex harness owning low-level session behavior such as thread resume, tool continuation, compaction, and app-server execution. It builds on the earlier Agents SDK and its evolution toward native sandbox execution and a model-native harness.
Source evidence: OpenAI Blog