OpenAI Opens Agents API Beta, Lets Developers Build on Codex Harness
OpenAI released the public beta of its Agents API, aimed at developers building internal or customer-only AI agents.
1 source Sep 11
Reporting from 1 source: GIGAZINE.
Why it matters
OpenAI is selling the harness layer that most agent builders currently maintain themselves, and the self-hosted sandbox path through Oracle and Cloudflare tells developers where in the stack OpenAI is willing to let third parties stay.
A harness that handles prompt formatting, tool use, context management and long-running sessions is required for agent work, and the Agents API lets developers use the same harness as Codex instead of maintaining their own. Tool calls run in a sandbox, either OpenAI-hosted or self-hosted through providers including Oracle and Cloudflare.
The Agents API runs the loop an agent needs: it reads the input, executes tool calls, runs the processing inside a sandbox, and returns results. Sandboxes come in two forms. Developers can use OpenAI-hosted sandboxes or self-hosted ones supplied by providers such as Oracle and Cloudflare.
Using the API itself costs nothing. Model usage through the API is billed per model. A quickstart guide covers the first build.
Written with AI by Yomimono from the 1 cited source below, including Japanese-language reporting where cited. See our editorial policy.
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