Run an agent through Core with the official OpenAI Python SDK: connect with a Project API key, start a Session that writes a file, and read the result. You need the key and the API base URL from your administrator.

Before you start, have:

• a Project API key and the API base URL (Issue a Project API key);
• a ready node, or an E2B or OpenSandbox backend, so Core has somewhere to run the agent (Add and manage nodes);
• Python 3.9 or newer;
• a model: the installation's default model, or your own provider's model ID, base URL and API key. Model execution says which one a Session uses and which protocols each Harness speaks.

The example uses Codex, whose model provider must speak the OpenAI Responses API.

1. Connect

Core serves the OpenAI Agents API, so the official OpenAI SDK works unchanged. It reads two environment variables:

Variable	Value
OPENAI_BASE_URL	The API base URL: the public URL plus /v1, such as https://core.example/v1. Web's Settings → Service and deployment page shows it
OPENAI_API_KEY	Your Project API key

python3 -m venv .venv
. .venv/bin/activate
pip install openai==3.45.0
export OPENAI_BASE_URL=https://core.example/v1
read -rs OPENAI_API_KEY && export OPENAI_API_KEY   # paste the key; it is not echoed

Check access. This runs no model and creates no sandbox:

Python

from openai import OpenAI

client = OpenAI()  # reads OPENAI_BASE_URL and OPENAI_API_KEY
print(client.beta.agents.list().data)

curl

curl "$OPENAI_BASE_URL/agents" -H "OpenAI-Beta: agents=v1" \
  -H @<(printf 'Authorization: Bearer %s\n' "$OPENAI_API_KEY")

An empty list ([]) means you are connected.

2. Start a Session

A Session is one agent conversation with its own workspace. With openai_hosted, Core creates a sandbox for it on a node, E2B or OpenSandbox and starts the Harness inside.

To use your own provider instead of the installation's default model, export its settings and run the second tab:

export MODEL_NAME='your-model-id'
export MODEL_BASE_URL='https://your-provider.example/v1'
read -rs MODEL_API_KEY && export MODEL_API_KEY

Default model

session = client.beta.agents.sessions.create(
    environment={"type": "openai_hosted"},
    input="Create /workspace/hello.txt with a short greeting, then describe it.",
    extra_body={"agent": {"x_agents_core": {"harness": "codex"}}},
)
print(session.id)

Your own provider

import os

session = client.beta.agents.sessions.create(
    environment={"type": "openai_hosted"},
    input="Create /workspace/hello.txt with a short greeting, then describe it.",
    extra_body={
        "agent": {"model": os.environ["MODEL_NAME"], "x_agents_core": {"harness": "codex"}},
        "x_agents_core": {"model_provider": {
            "protocol": "responses",
            "base_url": os.environ["MODEL_BASE_URL"],
            "api_key": os.environ["MODEL_API_KEY"],
        }},
    },
)
print(session.id)

This makes a real model request and may incur charges.

• x_agents_core holds Core's additions to the OpenAI API; see Core extensions.
• Keep the whole agent object in extra_body. SDK 3.45.0 replaces a body field with the matching extra_body field instead of merging them.

3. Wait for the result

A Session ID confirms creation, not success. Poll durable state; never resubmit to "retry":

import time

for _ in range(120):
    turns = client.beta.agents.sessions.turns.list(session.id, order="desc").data
    if turns and turns[0].status in {"completed", "failed", "cancelled"}:
        turn = turns[0]
        print("Turn:", turn.id, turn.status)
        print(client.beta.agents.sessions.items.list(session.id).data)
        break
    if client.beta.agents.sessions.retrieve(session.id).status == "failed":
        raise RuntimeError("Session preparation failed; inspect its Environment")
    time.sleep(1)
else:
    raise TimeoutError(f"Session {session.id} is still running; inspect it before retrying")

It prints:

Turn: 00000000-0000-4000-8000-000000000003 completed
[…the Turn's Items, including the assistant message that describes /workspace/hello.txt…]

A completed Turn whose Items describe the new file means the agent ran. A timeout neither cancels the work nor proves it failed.

Next steps

To	Read
Stream output, send follow-up messages, upload files, add Skills or MCP, cancel	Agents API guide
See every resource with request and response examples	Agents API guide
Run the agent on your own machine	Run self-hosted Sessions
See a complete application	Examples