Exploring Blockchain Data

Overview

Query and analyze blockchain data across multiple EVM-compatible networks including Ethereum, Polygon, Arbitrum, Optimism, and BSC. Supports transaction lookups, address balance checks, block inspection, token balance queries, transaction history retrieval, and whale wallet tracking via a unified CLI.

Prerequisites

• Python 3.8+ with requests and web3 libraries installed (pip install requests web3)
• Etherscan API key (free tier provides 5 requests/second; set via ETHERSCAN_API_KEY environment variable)
• Optional: API keys for Polygonscan, Arbiscan, and other chain-specific explorers for higher rate limits
• blockchain_explorer.py CLI script, chain_client.py, and token_resolver.py modules available in the plugin directory
• RPC endpoint access (public endpoints work; dedicated providers like Alchemy, Infura, Chainstack, or QuickNode recommended for reliability)

Instructions

1. Set the Etherscan API key as an environment variable: export ETHERSCAN_API_KEY=<key> to unlock higher rate limits beyond the default 5 requests/second.
2. Run python blockchain_explorer.py tx <hash> to look up a transaction by hash, returning status, block number, from/to addresses, value transferred, and gas details.
3. Append --detailed to the transaction query to decode the function call, identify the interacting protocol, and display input parameters.
4. Specify --chain polygon, --chain arbitrum, or --chain bsc to query transactions on alternative EVM chains when the hash is not found on Ethereum.
5. Run python blockchain_explorer.py address <address> to check the native token balance and total transaction count for a wallet.
6. Add --history --limit 50 to the address query to retrieve the most recent 50 transactions with timestamps, values, and counterparties.
7. Add --tokens to the address query to list all ERC-20 token holdings with balances, symbols, and USD values via CoinGecko price resolution.
8. Run python blockchain_explorer.py block latest to inspect the most recent block, or python blockchain_explorer.py block <number> for a specific block.
9. Run python blockchain_explorer.py token <wallet> <contract> to check the balance of a specific ERC-20 token at a wallet address, with automatic decimal and symbol resolution.
10. Export any query result in JSON or CSV format using --format json or --format csv and redirect to a file for downstream processing.
11. Enable verbose mode with --verbose to display API request URLs, response times, cache hit/miss status, and rate limit counters for debugging.

See ${CLAUDE_SKILL_DIR}/references/implementation.md for the full four-step implementation workflow.

Output

• Transaction detail tables showing hash, chain, status, block number, from/to addresses, value, gas price (Gwei), gas limit, gas used, and gas cost
• Decoded transaction data with function name, protocol identification, and parsed input parameters (when --detailed is used)
• Address summary with native balance, transaction count, and explorer link
• Transaction history tables with timestamp, hash, from/to, value, and direction (in/out)
• Token balance listings with contract address, token name, symbol, raw balance, human-readable balance, and USD value
• Block details with block number, timestamp, transaction count, gas used, and miner/validator
• JSON (output.json) or CSV (transactions.csv) export files for programmatic consumption

Error Handling

Examples

Look Up a Transaction Across Chains

# Try Ethereum first, then Polygon if not found
python blockchain_explorer.py tx 0x1234...abcdef --chain ethereum
python blockchain_explorer.py tx 0x1234...abcdef --chain polygon

Returns a formatted table with transaction status, block number, value transferred, gas details, and a link to the block explorer. Adding --detailed decodes the function call (e.g., swapExactTokensForTokens on Uniswap).

Full Wallet Analysis

python blockchain_explorer.py address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 --history --tokens --limit 50

Produces a wallet summary (ETH balance, total transaction count), the 50 most recent transactions with timestamps and counterparties, and a complete ERC-20 token holdings list with USD values. Useful for whale watching or due diligence on a wallet.

Check USDC Balance and Export to JSON

python blockchain_explorer.py token 0xYourWallet 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 --format json > usdc_balance.json

Resolves the USDC contract, fetches the wallet balance with proper decimal handling (6 decimals for USDC), includes the current USD price, and writes the result to usdc_balance.json for integration with dashboards or alerting pipelines.

Resources

• Etherscan API Documentation -- primary explorer API for Ethereum; free tier available with registration
• CoinGecko API -- token price resolution and metadata lookup
• web3.py Documentation -- Python library for direct RPC interaction with EVM chains
• Alchemy / Infura / QuickNode -- dedicated RPC providers for reliable node access
• 4byte.directory -- function signature database for decoding unverified contract interactions