BlockRun: AgentOps

Ampersend and BlockRun provide infrastructure for secure, observable, and programmable AI agent payments using x402, A2A communication, and onchain authorization flows.

This guide shows how to:

• Run buyer and seller AI agents locally
• Process AI-to-AI payments through x402
• Connect agents to BlockRun using X402Transport
• Configure smart accounts and session keys
• Test autonomous payment workflows on Base Sepolia

The example architecture uses:

• ADK Agents
• LiteLLM
• x402 payment flows
• BlockRun inference APIs
• Base Sepolia testnet infrastructure

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Architecture

Buyer
  ↓
A2A (x402: buyer pays seller)
  ↓
Seller (ADK Agent + LiteLLM)
  ↓
X402Transport
  ↓
BlockRun API

Components

Seller

An ADK Agent with a LiteLLM model backend.

Responsibilities:

• Receives A2A requests
• Charges buyers through x402
• Forwards requests to BlockRun through X402Transport
• Handles payment signing transparently

Buyer

A simple X402RemoteA2aAgent.

Responsibilities:

• Proxies requests to the seller via A2A
• Handles x402 payments automatically

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Setup

1. Install dependencies

uv sync

2. Start the seller

Run in Terminal 1:

uv run python examples/a2a_communication.py --seller

3. Run the Buyer

One-shot

Run in Terminal 2:

uv run python examples/a2a_communication.py --buyer --prompt "What is 2+2?"

Interactively via ADK

Run in Terminal 2:

uv run -- adk run src/blockrun_agent/buyer_a2a

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Environment Variables

Variable	Purpose
SELLER_SMART_ACCOUNT_ADDRESS	Seller wallet address. Receives buyer payments and pays BlockRun.
SELLER_SESSION_KEY	Seller session key used for signing.
BUYER_SMART_ACCOUNT_ADDRESS	Buyer wallet address used to pay the seller.
BUYER_SESSION_KEY	Buyer session key used for signing.
AMPERSEND_API_URL	Ampersend API endpoint. Default: https://api.staging.ampersend.ai

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Seller Setup

Programmatic setup

from blockrun_agent import SellerAgent, SellerConfig

config = SellerConfig(
    smart_account_address="0x...",
    session_key_private_key="0x...",
    network="base-sepolia",
    model="openai/gpt-oss-20b",
)

seller = SellerAgent(config=config)
await seller.serve()  # Starts on http://0.0.0.0:8001

Run with Uvicorn

uvicorn blockrun_agent.seller:a2a_app --port 8001

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Development

Install development tools

uv sync --group dev

Lint

uv run ruff check src/ examples/

Format

uv run ruff format src/ examples/

Type check

uv run mypy src/

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Testnet

BlockRun provides a Base Sepolia testnet environment for development.

Use testnet USDC from public faucets.

Setting	Mainnet	Testnet
API URL	https://blockrun.ai/api/v1	https://testnet.blockrun.ai/api/v1
Network	base (Chain 8453)	base-sepolia (Chain 84532)
Models	26 production models	openai/gpt-oss-20b, openai/gpt-oss-120b

Faucets

• Alchemy ETH Faucet
• Circle USDC Faucet

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On-Chain Proof

Verified Base Sepolia transaction showing the x402 payment flow.

Field	Value
Transaction	0xf77aca47...ecddd3
Network	Base Sepolia (Chain 84532)
Value	0.001 USDC
Method	transferWithAuthorization

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Additional Technical Information

For full source code, configuration files, and the latest updates, visit the official repository.

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