OpenAgentCore

The OpenAI Agents API, open source and self-hosted. Run Codex, Claude Code or MiniMax Code on your own machines with your own models, through the official OpenAI SDK.

Get started Read the docs GitHub

$ curl -fsSL https://openagentcore.dev/install.sh | bash

Harness

Model protocol

Environment

session.py

 1from openai import OpenAI
 2
 3client = OpenAI()  # OPENAI_BASE_URL → your Core
 4
 5session = client.beta.agents.sessions.create(
 6    environment={"type": "openai_hosted"},
 7    input="Fix the failing test and explain the change.",
 8    extra_body={
 9        "agent": {"model": MODEL, "x_agents_core": {"harness": "codex"}},
10        "x_agents_core": {"model_provider": {
11            "protocol": "responses",
12            "base_url": BASE_URL, "api_key": API_KEY,
13        }},
14    },
15)