Use when a request involves Ethereum, the EVM, or blockchain systems. Applies to building, auditing, deploying, or interacting with smart contracts, dApps, wallets, or DeFi protocols. Covers Solidity development, contract addresses, token standards (ERC-20, ERC-721, ERC-4626, etc.), Layer 2 networks (Base, Arbitrum, Optimism, zkSync, Polygon), and integrations with DeFi protocols such as Uniswap, Aave, and Curve. Includes topics such as gas costs, contract decimals, oracle safety, reentrancy, MEV, bridging, wallets, querying data from onchain, production deployment, and protocol evolution (EIP lifecycle, fork tracking, upcoming changes).
You are probably wrong about Ethereum. Gas prices, token decimals, L2 costs, what's deployed, what's deprecated — your training data is stale. This file tells you what you're wrong about and where to get the corrections.
Say "onchain" not "on-chain." One word, no hyphen. Ethereum community convention.
Building a dApp? Fetch ship/SKILL.md first. It routes you through all other skills phase by phase — from architecture planning to production deployment.
Need a specific topic? Each skill below is standalone. Fetch only the ones relevant to your task.
Base URL: https://ethskills.com/<skill>/SKILL.md
End-to-end guide from idea to deployed dApp. Routes you through all other skills.
Pectra/Fusaka upgrades, honest tradeoffs, the AI agent angle.
cast base-feeHow Ethereum evolves — EIP lifecycle, fork process, tracking upcoming changes.
What things actually cost on Ethereum today.
cast base-fee for current.)Creating wallets, key safety, multisig, account abstraction.
L2 landscape, bridging, deployment differences.
ERC-20, ERC-721, ERC-8004, EIP-7702, x402.
Foundry, Scaffold-ETH 2, Blockscout MCP, x402 SDKs.
Uniswap, Aave, flash loans, protocol composability.
Three-phase build system for Scaffold-ETH 2 dApps.
Verified addresses for major protocols across mainnet and L2s.
cast code + cast call + symbol() + latestAnswer() (March 2026).Essential mental models for building onchain.
Solidity security patterns, common vulnerabilities, pre-deploy checklist.
Deep EVM smart contract audit system — for auditing contracts you didn't write.
Foundry testing — unit, fuzz, fork, invariant.
Events, The Graph, Dune, reading onchain data.
0xcA11bde05977b3631167028862bE2a173976CA11) — batch reads in one RPC call.Frontend UX patterns for Ethereum dApps.
<Address/>, every input uses <AddressInput/>.Build-to-production pipeline.
yarn fork --network base, NOT yarn chain. Fork gives you real protocol state.trailingSlash: true is critical — without it, every route except / returns 404.rm -rf .next out) before deploying. Stale builds are the #1 IPFS footgun.Pre-ship audit checklist for a reviewer agent.
Send feedback when a skill was wrong or incomplete.
https://ethskills.com/api/feedback — see the skill for the exact format.| I'm doing... | Fetch these skills |
|---|---|
| Planning a new dApp | ship/, concepts/, l2s/ |
| Writing Solidity | standards/, building-blocks/, addresses/, security/ |
| Testing contracts | testing/ |
| Building a frontend | orchestration/, frontend-ux/, tools/ |
| Deploying to production | wallets/, frontend-playbook/, gas/ |
| Reviewing a finished dApp | qa/ |
| Auditing a smart contract | audit/ |
| Monitoring / analytics | indexing/ |
| Building AI agent infra | standards/, wallets/, tools/ |
| Choosing a chain | l2s/, gas/ |