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Read-only EVM client: wallets, tokens, gas across 8 chains.

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Skill metadata

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Reference: full SKILL.md

The following is the complete skill definition that Mibyan loads when this skill is triggered. This is what the agent sees as instructions when the skill is active.

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EVM Blockchain Skill

Query EVM-compatible blockchain data across 8 chains with USD pricing. 14 commands: wallet portfolio, token info, transactions, activity, gas tracker, network stats, price lookup, multi-chain scan, whale detection, ENS resolution, allowance checker, contract inspector, and transaction decoder. Supports 8 chains: Ethereum, BNB Chain (BSC), Base, Arbitrum One, Polygon, Optimism, Avalanche (C-Chain), zkSync Era. No API key needed. Zero external dependencies — Python standard library only (urllib, json, argparse, threading).
Supersedes the standalone base skill. Base-specific tokens (AERO, DEGEN, TOSHI, BRETT, WELL, cbETH, cbBTC, wstETH, rETH) and all Base RPC functionality previously living under optional-skills/blockchain/base/ have been folded into this skill. Pass --chain base to any command for Base coverage.

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When to Use

  • User asks for a wallet balance or portfolio on any EVM chain
  • User wants to check the same wallet across ALL chains at once
  • User wants to inspect a transaction by hash (or decode what it did)
  • User wants ERC-20 token metadata, price, supply, or market cap
  • User wants recent transaction history for an address
  • User wants current gas prices or to compare fees across chains
  • User wants to find large whale transfers in recent blocks
  • User asks to resolve an ENS name (vitalik.eth) or reverse-lookup an address
  • User wants to check if a contract has dangerous token approvals
  • User wants to inspect a smart contract (proxy? ERC-20? ERC-721? bytecode size?)
  • User wants to compare gas costs across chains before a transaction

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Prerequisites

Python 3.8+ standard library only. No pip installs required. Pricing: CoinGecko free API (rate-limited, ~10-30 req/min). ENS: ensideas.com public API. Tx decoding: 4byte.directory public API. Override RPC endpoint: export EVM_RPC_URL=https://your-rpc.com Helper script path: ~/.mibyan/skills/blockchain/evm/scripts/evm_client.py

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Quick Reference

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Procedure

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0. Setup Check

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1. Wallet Portfolio

Native balance + known ERC-20 tokens, sorted by USD value.

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2. Multi-Chain Scan

Scans all 8 chains simultaneously for the same address using threads.
Output: per-chain native balance + token holdings + grand total USD.

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3. Compare (Gas + Prices)

All 8 chains queried in parallel. Shows cheapest/most expensive chain.

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4. Transaction Details & Decode

Decode uses 4byte.directory to translate 0xa9059cbb -> transfer(address,uint256).

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5. ENS Resolution

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6. Allowance Checker (Security)

Checks ERC-20 approvals granted to known DEX/bridge contracts.
Flags UNLIMITED approvals as HIGH risk.

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7. Contract Inspector

Detects: proxy (EIP-1967/EIP-1167), ERC-20, ERC-721, ERC-165. Shows bytecode size and implementation address for proxies.

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8. Whale Detection

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9. Gas Tracker

Shows gwei price + USD cost for: transfer, ERC-20 transfer, approve, swap, NFT mint, NFT transfer.

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Supported Chains

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Pitfalls

  • CoinGecko free tier: ~10-30 req/min. Use --no-prices for faster wallet scans.
  • Public RPCs may throttle. Set EVM_RPC_URL to a private endpoint for production.
  • wallet and allowance only check known token list (~30 tokens per chain). Use a block explorer for complete token discovery.
  • activity scans recent blocks only (max 200). For full history, use Etherscan API.
  • multichain runs 8 parallel threads — can trigger rate limits on public RPCs.
  • ENS resolution depends on a single public endpoint (ensideas.com / ens.vitalik.ca) with no fallback. If that endpoint is down, ens will fail — re-run later or use a block explorer.
  • Tx decoding depends on a single public endpoint (4byte.directory) with no fallback. Selectors not in their database show up as unknown.
  • L2 gas estimates are L2-execution only. On rollups like Base, Arbitrum, Optimism, and zkSync, the actual transaction cost also includes an L1 data-posting fee that depends on calldata size and current L1 gas prices. The gas command does not estimate that L1 component. For Base specifically, see the network’s L1 fee oracle (contract 0x420000000000000000000000000000000000000F).
  • Address / tx-hash inputs are validated for 0x-prefix + correct length + hex, but EIP-55 checksum casing is not enforced (RPC endpoints accept any-case hex).

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Verification