How to Run an AI Blockchain & Web3 Agent with OE Runtime

Query Ethereum wallets, transactions, and smart contracts with natural language. OE Runtime lets you run a local Web3 agent — fetch balances, analyse transaction history, and surface on-chain insights without writing a single line of code.

What You Need

• Node.js 18+ installed, or the OE Runtime binary from openenthrium.com/runtime
• An API key from OpenAI, Anthropic, or any supported LLM provider
• A free public Ethereum RPC endpoint — no account needed (included in the config below)
• A text editor — nothing else

Create the Project Folder

Create a folder called blockchain-web3/ and add these two files:

The Skill Files

Create SKILL.md inside blockchain-web3/. This is the portable skill — it follows the agentskills.io format and runs unchanged on Claude, Cursor, Windsurf, or OE Runtime:

---
name: blockchain-web3
description: Check ETH wallet balance
license: Apache-2.0
metadata:
  author: Open Enthrium
  version: "1.0"
---

You are a blockchain data agent. Use the tools to fetch data and respond concisely.

## Step 1: Check Balance
Get the ETH balance for the configured wallet address.
Report the address and balance in ETH. Nothing else.

Create agent.yaml in the same directory to wire the skill to your connector:

name: Blockchain Agent
description: Check ETH wallet balance
connectors:
  - connection_name: Ethereum
    connection_type: web3
skills:
  - path: ./
    trigger_type: auto

The Config File

Create oe-config.json in the same directory. The RPC endpoint needs no API key — blockchain data is public:

{
  "llm": {
    "provider": "openai",
    "model": "gpt-4o",
    "apiKey": "YOUR_OPENAI_API_KEY"
  },
  "server": {
    "enabled": false,
    "port": 3333,
    "apiKey": "your-secret-api-key"
  },
  "connectors": [
    {
      "connection_name": "Ethereum",
      "connection_type": "web3",
      "baseUrl": "https://ethereum.publicnode.com",
      "walletAddress": "0xYOUR_WALLET_ADDRESS"
    }
  ]
}

The connector works with any EVM-compatible chain — all URLs below are free, no API key required. Just swap baseUrl in your oe-config.json:

Ethereum          https://ethereum.publicnode.com
BNB Smart Chain   https://bsc.publicnode.com
Polygon           https://polygon-bor.publicnode.com
Arbitrum          https://arbitrum-one.publicnode.com
Avalanche         https://avalanche-c-chain.publicnode.com
Base              https://base.publicnode.com
Optimism          https://optimism.publicnode.com

Download OE Runtime

Run the Agent

From the parent folder containing your skill directory:

1 npx recommended

npx -y @openenthrium/oe-runtime@latest ./blockchain-web3

2 Windows

oe-runtime-win.exe ./blockchain-web3

3 macOS

chmod +x oe-runtime-macos
./oe-runtime-macos ./blockchain-web3

First run blocked? System Settings → Privacy & Security → Allow Anyway.

4 Linux

chmod +x oe-runtime-linux
./oe-runtime-linux ./blockchain-web3

5 API Server integration

Add a "server" block to oe-config.json, then start with --serve:

{
  "llm": { ... },
  "server": { "enabled": true, "port": 3333, "apiKey": "your-secret-key" },
  "connectors": [ ... ]
}

npx -y @openenthrium/oe-runtime@latest --serve --config oe-config.json

Run with inline YAML:

curl -X POST http://localhost:3333/run \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-secret-key" \
  -d '{"yaml": "...", "params": {}}'

Or run from a file on the server:

curl -X POST http://localhost:3333/run-file \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-secret-key" \
  -d '{"file": "/path/to/agent.yaml", "params": {}}'

Use Cases

• Wallet auditing — Review the complete transaction history, token holdings, and ETH balance for any wallet address. Useful for compliance teams verifying that company wallets have not made unauthorised transfers or interacted with flagged contracts.
• DeFi portfolio monitoring — Track wallet positions across DeFi protocols by querying on-chain state directly. Get a consolidated view of lending positions, liquidity pool shares, and token balances without relying on third-party dashboards.
• Treasury management — Monitor DAO or company treasury wallets for incoming and outgoing transfers in real time. Set up the agent as an API server to trigger alerts whenever a transfer above a threshold is detected.
• On-chain due diligence — Research counterparty wallet history before entering a token deal or smart contract interaction. Surface red flags like interactions with mixer contracts, rapid fund movements, or connections to flagged addresses.
• NFT ownership verification — Confirm token ownership and provenance on-chain before processing a transfer or listing. Query the ERC-721 or ERC-1155 contract to get the current holder, mint date, and full transfer history.
• Smart contract inspection — Query the state variables and recent event logs of any deployed smart contract. Useful for developers auditing their own contracts or for analysts monitoring protocol activity.
• Transaction forensics — Trace the flow of funds across multiple wallet hops to reconstruct a payment path. Combine with the reporting step to produce a clear chain-of-custody document for legal or compliance purposes.
• Automated reporting — Run the agent on a schedule to generate daily or weekly blockchain activity reports for stakeholders. Deliver summaries of treasury movements, gas costs, and protocol interactions without manual data collection.