There is no OpenAI Agents SDK package, and you do not need one. The SDK turns a decorated function into a tool with , so you wrap the real Python client in a function and add it to your . The agent can send USDC, settle invoices, and read wallets - across single agents, handoffs, and the underlying Responses API. Payments settle on Base.

Install the Agents SDK and the core SDK. Two keys.

There is no blockchain0x Agents SDK package to add. You install the OpenAI Agents SDK (the openai-agents package, Python 3.10+) and the real blockchain0x core SDK, then write the function below. That is the whole dependency list.

pip install openai-agents blockchain0x

export OPENAI_API_KEY=sk-...
export BLOCKCHAIN0X_API_KEY=sk_test_...   # sk_test_ = Base Sepolia, sk_live_ = Base mainnet

OPENAI_API_KEY is your existing OpenAI key (the Agents SDK uses it for the underlying Responses API). BLOCKCHAIN0X_API_KEY is a sk_test_ testnet or sk_live_ mainnet key from your dashboard; the client reads it from the environment. If your agent also receives money, the webhook handler additionally needs BLOCKCHAIN0X_WEBHOOK_SECRET.

Confirm inbound payments with a signed webhook.

If your agent also receives USDC, confirm it with the webhook rather than polling. The verify helper ships in the Node SDK; in a Python service you verify by hand against the documented HMAC, which is all the helper does. FastAPI example below; the same code works in any async Python framework.

import hmac, hashlib, os, time
from fastapi import FastAPI, Request, HTTPException

app = FastAPI()
SECRET = os.environ["BLOCKCHAIN0X_WEBHOOK_SECRET"].encode()

@app.post("/webhooks/payment")
async def receive(request: Request):
    raw = await request.body()  # RAW bytes - do not parse first
    sig = request.headers.get("X-Blockchain0x-Signature", "")
    ts = request.headers.get("X-Blockchain0x-Timestamp", "")
    parts = dict(p.split("=", 1) for p in sig.split(",") if "=" in p)
    t, v1 = parts.get("t", ts), parts.get("v1", sig)
    want = hmac.new(SECRET, t.encode() + b"." + raw, hashlib.sha256).hexdigest()
    if not hmac.compare_digest(want, v1) or abs(time.time() - int(t)) > 300:
        raise HTTPException(status_code=401)
    if request.headers.get("X-Blockchain0x-Event-Type") == "payment.received":
        await trigger_followup()  # USDC landed - run the next step
    return {"ok": True}

The algorithm is HMAC-SHA256 over the string t.rawBody, a constant-time compare, and a 300-second replay window. Read the raw body via await request.body(), never request.json() re-serialized, because that changes the bytes the signature covers. The shipped events are payment.received, payment.sent, wallet.deployed, and webhook.test. For heavy follow-up work, enqueue a job (Celery, arq) and respond 200 immediately rather than blocking the handler.

Five things to watch on first integration.

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