Skill: szkkhh/megaethss-developer (version 1.0.0)

--- name: megaethss-developer description: End-to-end MegaETH development playbook (Feb 2026). Covers Foundry project setup with MegaETH-specific config, wallet operations, token swaps (Kyber Network), eth_sendRawTransactionSync (EIP-7966) for instant receipts, JSON-RPC batching, real-time mini-block subscriptions, storage-aware contract patterns (Solady RedBlackTreeLib, transient storage), MegaEVM multidimensional gas model, WebSocket keepalive, bridging from Ethereum, Privy headless signing for ultra-low latency, debugging with mega-evme, Meridian x402 payments on MegaETH (seller-side settlement plus buyer-side USDm forwarder approvals and EIP-712 authorizations), and Warren Protocol for on-chain website hosting. Use when building on MegaETH, using Foundry, managing wallets, sending transactions, deploying contracts, integrating Privy embedded wallets, ERC-7710 delegation framework for scoped on-chain permissions, MetaMask Smart Accounts Kit for smart account creation and delegation management, integrating Meridian/x402 paid APIs or agent actions, hosting websites on-chain with Warren, or integrating MegaNames (.mega naming service) for name registration, resolution, subdomains, subdomain marketplace (selling/buying subdomains with token gating), and text records. --- # MegaETH Development Skill ## What this Skill is for Use this Skill when the user asks for: - Foundry project setup targeting MegaETH - Writing and running tests (unit, fuzz, invariant) on MegaETH - Deploying and verifying contracts on MegaETH - Wallet setup and management on MegaETH - Sending transactions, checking balances, token operations - Token swaps via Kyber Network aggregator - MegaETH dApp frontend (React / Next.js with real-time updates) - RPC configuration and transaction flow optimization - Smart contract development with MegaEVM considerations - Storage optimization (transient storage, Solady patterns) - Gas estimation and fee configuration - Testing and debugging MegaETH transactions - WebSocket subscriptions and mini-block streaming - Bridging ETH from Ethereum to MegaETH - Privy integration for headless/automated signing - Meridian / x402 payments on MegaETH - Ultra-low latency transaction patterns - ERC-7710 delegations (scoped permissions, spending limits, redelegation chains) - MetaMask Smart Accounts (ERC-4337 accounts, signers, user operations) - Advanced permissions (ERC-7715) via MetaMask - MegaNames (.mega naming service) — registration, resolution, subdomains, subdomain marketplace, text records ## Chain Configuration | Network | Chain ID | RPC | Explorer | |---------|----------|-----|----------| | Mainnet | 4326 | `https://mainnet.megaeth.com/rpc` | `https://mega.etherscan.io` | | Testnet | 6343 | `https://carrot.megaeth.com/rpc` | `https://megaeth-testnet-v2.blockscout.com` | ## Default stack decisions (opinionated) ### 1. Transaction submission: eth_sendRawTransactionSync first - Use `eth_sendRawTransactionSync` (EIP-7966) — returns receipt in <10ms - Eliminates polling for `eth_getTransactionReceipt` - Docs: https://docs.megaeth.com/realtime-api ### 2. RPC: Multicall for eth_call batching (v2.0.14+) - Prefer Multicall (`aggregate3`) for batching multiple `eth_call` requests - As of v2.0.14, `eth_call` is 2-10x faster; Multicall amortizes per-RPC overhead - Still avoid mixing slow methods (`eth_getLogs`) with fast ones in same request **Note:** Earlier guidance recommended JSON-RPC batching over Multicall for caching benefits. With v2.0.14's performance improvements, Multicall is now preferred. ### 3. WebSocket: keepalive required - Send `eth_chainId` every 30 seconds - 50 connections per VIP endpoint, 10 subscriptions per connection - Use `miniBlocks` subscription for real-time data ### 4. Storage: slot reuse patterns - SSTORE 0→non-zero costs 2M gas × multiplier (expensive) - Use Solady's RedBlackTreeLib instead of Solidity mappings - Design for slot reuse, not constant allocation ### 5. Gas: skip estimation when possible - Base fee stable at 0.001 gwei, no EIP-1559 adjustment - Ignore `eth_maxPriorityFeePerGas` (returns 0) - Hardcode gas limits to save round-trip - Always use remote `eth_estimateGas` (MegaEVM costs differ from standard EVM) ### 6. Debugging: mega-evme CLI - Replay transactions with full traces - Profile gas by opcode - https://github.com/megaeth-labs/mega-evm ## Operating procedure ### 1. Classify the task layer - Frontend/WebSocket layer - RPC/transaction layer - Smart contract layer - Testing/debugging layer ### 2. Pick the right patterns - Frontend: single WebSocket → broadcast to users (not per-user connections) - Transactions: sign locally → `eth_sendRawTransactionSync` → done - Contracts: check SSTORE patterns, avoid volatile data access limits - Testing: use mega-evme for replay, Foundry with `--skip-simulation` - Delegations: create scoped permissions → sign → share → redeem via `eth_sendRawTransactionSync` ### 3. Implement with MegaETH-specific correctness Always be explicit about: - Chain ID (4326 mainnet, 6343 testnet) - Gas limit (hardcode when possible) - Base fee (0.001 gwei, no buffer) - Storage costs (new slots are expensive) - Volatile data limits (20M total compute gas cap, retroactive, when block.timestamp accessed) ### 4. Deliverables expectations When implementing changes, provide: - Exact files changed + diffs - Commands to build/test/deploy - Gas cost notes for storage-heavy operations - RPC optimization notes if applicable ## Progressive disclosure (read when needed) - Foundry setup & deploy: [foundry-config.md](foundry-config.md) - Wallet operations: [wallet-operations.md](wallet-operations.md) - Frontend patterns: [frontend-patterns.md](frontend-patterns.md) - Privy integration: [privy-integration.md](privy-integration.md) - Meridian payments: [meridian.md](meridian.md) - RPC methods reference: [rpc-methods.md](rpc-methods.md) - Smart contract patterns: [smart-contracts.md](smart-contracts.md) - Storage optimization: [storage-optimization.md](storage-optimization.md) - Gas model: [gas-model.md](gas-model.md) - Testing & debugging: [testing.md](testing.md) - Security considerations: [security.md](security.md) - ERC-7710 delegations: [erc7710-delegations.md](erc7710-delegations.md) - MetaMask Smart Accounts: [smart-accounts.md](smart-accounts.md) - Warren Protocol (on-chain websites): [warren.md](warren.md) - MegaNames (.mega naming): [meganames.md](meganames.md) - Reference links & attribution: [resources.md](resources.md)


Security scan verdicts — ClawScan: suspicious | static analysis: clean | VirusTotal: clean | SkillSpector: suspicious (CRITICAL)