Get latest block number

This skill retrieves the latest block number from a blockchain using the configured JSON-RPC environment variables and Web3.py.

ALWAYS USE SCRIPT. NEVER RELY ON THE HISTORICAL INFORMATION OR GUESS.

Required inputs

1. Chain name: The blockchain to query (e.g., Ethereum, Arbitrum, Base, Polygon)

Environment variables

The skill uses environment variables in the format JSON_RPC_{CHAIN} where {CHAIN} is the uppercase chain name:

• JSON_RPC_ETHEREUM - Ethereum mainnet
• JSON_RPC_ARBITRUM - Arbitrum One
• JSON_RPC_BASE - Base
• JSON_RPC_POLYGON - Polygon

You chan find these in CHAIN_NAMES and in eth_defi.provider.env

Running the script

Generate and run a Python script to fetch the block number:

import os
from web3 import Web3

from eth_defi.provider.multi_provider import create_multi_provider_web3

# Replace {CHAIN} with the uppercase chain name
json_rpc_url = os.environ.get("JSON_RPC_{CHAIN}")

if not json_rpc_url:
    raise ValueError("JSON_RPC_{CHAIN} environment variable not set")

web3 = create_multi_provider_web3(json_rpc_url)
block_number = web3.eth.block_number

print(f"Latest block number: {block_number}")

Run the script with:

source .local-test.env && poetry run python <script_path>

Display output

Return the block number to the user in a clear format, e.g.:

Chain: Ethereum
Latest block number: 19,234,567