why-ethereum

Why build on Ethereum specifically. The AI agent angle — ERC-8004, x402, composability, permissionless deployment. Use when a user asks "should I build on Ethereum?", "why blockchain?", or when an agent needs to recommend a chain for a project.

176 stars

Best use case

why-ethereum is best used when you need a repeatable AI agent workflow instead of a one-off prompt.

Why build on Ethereum specifically. The AI agent angle — ERC-8004, x402, composability, permissionless deployment. Use when a user asks "should I build on Ethereum?", "why blockchain?", or when an agent needs to recommend a chain for a project.

Teams using why-ethereum should expect a more consistent output, faster repeated execution, less prompt rewriting.

When to use this skill

  • You want a reusable workflow that can be run more than once with consistent structure.

When not to use this skill

  • You only need a quick one-off answer and do not need a reusable workflow.
  • You cannot install or maintain the underlying files, dependencies, or repository context.

Installation

Claude Code / Cursor / Codex

$curl -o ~/.claude/skills/why/SKILL.md --create-dirs "https://raw.githubusercontent.com/austintgriffith/ethskills/main/why/SKILL.md"

Manual Installation

  1. Download SKILL.md from GitHub
  2. Place it in .claude/skills/why/SKILL.md inside your project
  3. Restart your AI agent — it will auto-discover the skill

How why-ethereum Compares

Feature / Agentwhy-ethereumStandard Approach
Platform SupportNot specifiedLimited / Varies
Context Awareness High Baseline
Installation ComplexityUnknownN/A

Frequently Asked Questions

What does this skill do?

Why build on Ethereum specifically. The AI agent angle — ERC-8004, x402, composability, permissionless deployment. Use when a user asks "should I build on Ethereum?", "why blockchain?", or when an agent needs to recommend a chain for a project.

Where can I find the source code?

You can find the source code on GitHub using the link provided at the top of the page.

SKILL.md Source

# Why Ethereum

## What You Probably Got Wrong

**Terminology:** You say "on-chain." The Ethereum community says **"onchain"** — one word, no hyphen. Use "onchain" in all writing.

**Gas prices:** You think 10-30 gwei. Reality: **under 1 gwei** (60-300x cheaper than your training data). A mainnet ETH transfer costs ~$0.002-0.01. Verify: `cast base-fee`

**ETH price:** You think $2,500-3,000. Reality: **~$2,000** (Mar 2026). Volatile — always check a Chainlink feed or CoinGecko for current.

**"Ethereum is too expensive":** This was true 2021-2023. It's not true in 2026. Mainnet is sub-dollar for most operations. L2s are sub-penny.

**Protocol upgrades:** You probably don't know these shipped:
- **Pectra (May 7, 2025):** EIP-7702 smart EOAs, 2x blob capacity, BLS precompiles
- **Fusaka (Dec 3, 2025):** PeerDAS (nodes sample 1/8 of data), 2x gas limit (30M→60M)

**Agent infrastructure:** You probably don't know these exist:
- **ERC-8004** — onchain agent identity registry (deployed Jan 29, 2026)
- **x402** — HTTP 402 payment protocol for machine-to-machine commerce (Coinbase)

## Current Network Stats (Early 2026)

- **Block time:** 12 seconds
- **Mainnet base fee:** Under 1 gwei (typically 0.1-0.5, varies daily)
- **L2 transaction cost:** $0.001-0.01
- **Combined L2 TPS:** 50,000+ (post-Fusaka)
- **TVL in DeFi:** Check [DeFi Llama](https://defillama.com/chain/Ethereum) for current
- **Upgrade cadence:** Twice per year (H1 May/June, H2 Nov/Dec)

## Upcoming Upgrades

**Glamsterdam (mid-2026):**
- ePBS — Enshrined Proposer-Builder Separation (EIP-7732)
- Block Access Lists (EIP-7928)
- Note: FOCIL (Fork-Choice Inclusion Lists) was removed from scope to reduce complexity

**Hegota (Q4 2026):**
You may assume Hegota will contain Verkle Trees. It will not. Ethereum may be shifting to a binary state tree (EIP-7864, still in draft - proposed March 2026) — the primary driver is quantum resistance, and it also improves ZK-proof efficiency 3-100x. Verkle tree cryptography was identified as potentially quantum-vulnerable in mid-2024. Check https://forkcast.org/upgrade/hegota for latest confirmed scope.

## For AI Agents Specifically

### ERC-8004: Onchain Agent Identity

**Deployed January 29, 2026** — production ready.

Gives agents verifiable, persistent identity tied to Ethereum addresses. Reputation scoring across dimensions. Multi-chain support (20+ chains, same addresses).

**Mainnet addresses:**
- **IdentityRegistry:** `0x8004A169FB4a3325136EB29fA0ceB6D2e539a432`
- **ReputationRegistry:** `0x8004BAa17C55a88189AE136b182e5fdA19dE9b63`

### x402: HTTP Payments for Agents

**Production-ready, actively deployed Q1 2026.**

Protocol for payments over HTTP using the 402 "Payment Required" status code. Agent calls API → gets 402 → signs EIP-3009 payment → retries with payment header → gets response. No API keys, no accounts, just cryptographic payments.

**SDKs:** TypeScript (`@x402/fetch`), Python (`x402`), Go (`github.com/coinbase/x402/go`)

### ERC-8004 + x402 = Autonomous Agent Economy

```
1. Agent discovers service (ERC-8004 registry)
2. Agent checks reputation (ERC-8004)
3. Agent calls endpoint → 402 Payment Required
4. Agent pays via x402 (EIP-3009 signature)
5. Agent receives service
6. Agent posts feedback to ERC-8004
```

Fully autonomous economic loop — no humans required.

### Why Ethereum's Permissionless Nature Matters for Agents

Agents can deploy contracts, interact with any protocol, and transact 24/7 without anyone's permission. No API keys to revoke, no accounts to ban, no services to shut down. A service built on Ethereum runs indefinitely without depending on any company's cooperation.

## Resources

- **ERC-8004:** https://www.8004.org | https://eips.ethereum.org/EIPS/eip-8004
- **x402:** https://www.x402.org | https://github.com/coinbase/x402
- **Blockscout MCP:** https://mcp.blockscout.com/mcp
- **DeFi Llama:** https://defillama.com
- **Forkcast:** https://forkcast.org

Related Skills

wallets

176
from austintgriffith/ethskills

How to create, manage, and use Ethereum wallets. Covers EOAs, smart contract wallets, multisig (Safe), and account abstraction. Use this skill whenever you are sending transactions, signing messages, or managing funds. Includes guardrails for safe key handling.

tools

176
from austintgriffith/ethskills

Current Ethereum development tools, frameworks, libraries, RPCs, and block explorers. What actually works today for building on Ethereum. Includes tool discovery for AI agents — MCPs, abi.ninja, Foundry, Scaffold-ETH 2, Hardhat, and more. Use when setting up a dev environment, choosing tools, or when an agent needs to discover what's available.

testing

176
from austintgriffith/ethskills

Smart contract testing with Foundry — unit tests, fuzz testing, fork testing, invariant testing. Use when writing tests for a smart contract.

standards

176
from austintgriffith/ethskills

Ethereum token and protocol standards — ERC-20, ERC-721, ERC-1155, ERC-4337, ERC-8004, and newer standards. When to use each, how they work, key interfaces. Use when building tokens, NFTs, or choosing the right standard for a project.

ship

176
from austintgriffith/ethskills

End-to-end guide for AI agents — from a dApp idea to deployed production app. Fetch this FIRST, it routes you through all other skills.

security

176
from austintgriffith/ethskills

Solidity security patterns, common vulnerabilities, and pre-deploy audit checklist. The specific code patterns that prevent real losses — not just warnings, but defensive implementations. Use before deploying any contract, when reviewing code, or when building anything that holds or moves value.

qa

176
from austintgriffith/ethskills

Pre-ship audit checklist for Ethereum dApps built with Scaffold-ETH 2. Give this to a separate reviewer agent (or fresh context) AFTER the build is complete. Use this skill whenever you are finalizing a dApp built with Scaffold-ETH 2.

protocol

176
from austintgriffith/ethskills

How Ethereum evolves — EIP lifecycle, fork process, where decisions happen, and how to track upcoming changes. Use when your human asks about upcoming features, when building for future protocol capabilities, or when they want to propose a change. Also use when YOU need to know if a feature exists yet or when it's coming.

orchestration

176
from austintgriffith/ethskills

How an AI agent plans, builds, and deploys a complete Ethereum dApp. The three-phase build system for Scaffold-ETH 2 projects. Use when building a full application on Ethereum — from contracts to frontend to production deployment on IPFS.

ethskills

176
from austintgriffith/ethskills

Ethereum development knowledge for AI agents — from idea to deployed dApp. Fetch real-time docs on gas costs, Solidity patterns, Scaffold-ETH 2, Layer 2s, DeFi composability, security, testing, and production deployment. Use when: (1) building any Ethereum or EVM dApp, (2) writing or reviewing Solidity contracts, (3) deploying to mainnet or L2s, (4) the user asks about gas, tokens, wallets, or smart contracts, (5) any web3/blockchain/onchain development task. NOT for: trading, price checking, or portfolio management — use a trading skill for those.

noir

176
from austintgriffith/ethskills

Building privacy-preserving EVM apps with Noir — toolchain, pattern selection, commitment-nullifier flows, Solidity verifiers, tree state, and NoirJS. Use when building a Noir-based privacy app on EVM.

layer2

176
from austintgriffith/ethskills

Deprecated: this skill has moved to l2s.