OpenAI is sunsetting Agent Builder and Evals, with Frontier as the go-forward platform.

AgentKit's Agent Builder and Evals come off the platform November 30, 2026, replaced by OpenAI Frontier for building, deploying, and governing agents with shared context and permissions (customers include HP, Oracle, State Farm, Uber) (OpenAI). OpenAI says Frontier doesn't replace the Agents SDK or remaining APIs. If you built on Agent Builder, you need a migration plan now, not in November. This is the second time in a year I've watched OpenAI deprecate an agent-building surface, so factor platform churn into anything you build on their tooling.