OpenAI DevDay 2026: What the Agents API and Decisions API Teach About API Design

Wed, 07 Oct 2026 00:00:00 +0000

OpenAI’s DevDay last week was mostly pitched as an agents event. Persistent agents, cloud Codex, a cheaper model. Fine. But if you’re learning to build and design APIs, two of the smaller releases are worth more of your attention than the headline model, because they say a lot about where API contracts are going.

Here’s what shipped, then what to take from it.

What OpenAI released

The Agents API is now in public beta. It runs agents on OpenAI’s own infrastructure, with memory, tool calling, tool search, context compaction and multi-agent support carried over from Codex. The new piece is computer use: an agent can now drive software through its graphical interface, clicking and typing the way a person would.

Openai on API Course

OpenAI DevDay 2026: What the Agents API and Decisions API Teach About API Design

What OpenAI released