Ethereum Development

Ethereum Development Skill

Master Ethereum development including EVM internals, gas optimization, transaction mechanics, and client interactions.

Quick Start

# Invoke this skill for Ethereum development
Skill("ethereum-development", topic="gas", network="mainnet")

Topics Covered

1. EVM (Ethereum Virtual Machine)

Understand the execution environment:

• Stack Machine: 256-bit words, 1024 depth
• Memory: Linear byte array, expansion costs
• Storage: Persistent key-value, 32-byte slots
• Opcodes: Costs, effects, gas consumption

2. Gas Optimization

Reduce transaction costs:

• Storage Packing: Fit multiple values in one slot
• Calldata vs Memory: Choose efficiently
• Loop Optimization: Cache storage reads
• Custom Errors: Save gas on reverts

3. Transaction Mechanics

Master transaction lifecycle:

• Types: Legacy (0), Access List (1), EIP-1559 (2)
• Fee Estimation: Base fee, priority fee, max fee
• Nonce Management: Sequential ordering
• Receipts: Status, logs, gas used

4. Client Interactions

Work with Ethereum nodes:

• RPC Methods: eth_, debug_, trace_
• State Queries: Storage slots, code, balance
• Event Subscriptions: Filter logs, topics

Code Examples

Gas-Efficient Storage

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract Optimized {
    // Pack into single slot (32 bytes)
    struct User {
        uint128 balance;    // 16 bytes
        uint64 lastUpdate;  // 8 bytes
        uint32 nonce;       // 4 bytes
        bool active;        // 1 byte
        // 3 bytes padding
    }

    mapping(address => User) public users;
}

Read Storage Slot

import { createPublicClient, http, keccak256, encodePacked, pad } from 'viem';
import { mainnet } from 'viem/chains';

const client = createPublicClient({ chain: mainnet, transport: http() });

// Read mapping value: balances[address]
async function getBalance(contract: `0x${string}`, user: `0x${string}`) {
  const slot = keccak256(encodePacked(['address', 'uint256'], [user, 0n]));
  return await client.getStorageAt({ address: contract, slot });
}

EIP-1559 Transaction

import { createWalletClient, http, parseEther } from 'viem';

const client = createWalletClient({ transport: http() });

const hash = await client.sendTransaction({
  to: '0x...',
  value: parseEther('0.1'),
  type: 'eip1559',
  maxFeePerGas: parseGwei('30'),
  maxPriorityFeePerGas: parseGwei('2'),
});

Gas Optimization Cheatsheet

Common Pitfalls

Troubleshooting

"Transaction underpriced"

# Check current gas prices
cast gas-price --rpc-url $RPC
cast basefee --rpc-url $RPC

Set maxFeePerGas to at least 2x current base fee.

"Out of gas"

# Trace transaction to find issue
cast run --trace $TX_HASH --rpc-url $RPC

"Nonce too low"

# Get current nonce
cast nonce $ADDRESS --rpc-url $RPC

CLI Commands

# Foundry essentials
forge build --sizes          # Contract sizes
forge test --gas-report      # Gas consumption
forge snapshot               # Gas snapshots
cast storage $ADDR $SLOT     # Read storage
cast call $ADDR "fn()"       # Simulate call

Test Template

contract GasTest is Test {
    function test_GasOptimization() public {
        uint256 gasBefore = gasleft();
        target.optimizedFunction();
        uint256 gasUsed = gasBefore - gasleft();

        assertLt(gasUsed, 50000, "Too much gas used");
    }
}

Cross-References

• Bonded Agent: 02-ethereum-development
• Related Skills: solidity-development, web3-frontend

Version History

Ethereum Development Guide

Overview

This guide provides comprehensive documentation for the ethereum-development skill in the custom-plugin-blockchain plugin.

Category: General

Quick Start

Prerequisites

• Familiarity with general concepts
• Development environment set up
• Plugin installed and configured

Basic Usage

# Invoke the skill
claude "ethereum-development - [your task description]"

# Example
claude "ethereum-development - analyze the current implementation"

Core Concepts

Key Principles

1. Consistency - Follow established patterns 2. Clarity - Write readable, maintainable code 3. Quality - Validate before deployment

Best Practices

• Always validate input data
• Handle edge cases explicitly
• Document your decisions
• Write tests for critical paths

Common Tasks

Task 1: Basic Implementation

# Example implementation pattern
def implement_ethereum_development(input_data):
    """
    Implement ethereum-development functionality.

    Args:
        input_data: Input to process

    Returns:
        Processed result
    """
    # Validate input
    if not input_data:
        raise ValueError("Input required")

    # Process
    result = process(input_data)

    # Return
    return result

Task 2: Advanced Usage

For advanced scenarios, consider:

• Configuration customization via assets/config.yaml
• Validation using scripts/validate.py
• Integration with other skills

Troubleshooting

Common Issues

Related Resources

• SKILL.md - Skill specification
• config.yaml - Configuration options
• validate.py - Validation script

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Last updated: 2025-12-30

Ethereum Development Patterns

Design Patterns

Pattern 1: Input Validation

Always validate input before processing:

def validate_input(data):
    if data is None:
        raise ValueError("Data cannot be None")
    if not isinstance(data, dict):
        raise TypeError("Data must be a dictionary")
    return True

Pattern 2: Error Handling

Use consistent error handling:

try:
    result = risky_operation()
except SpecificError as e:
    logger.error(f"Operation failed: {e}")
    handle_error(e)
except Exception as e:
    logger.exception("Unexpected error")
    raise

Pattern 3: Configuration Loading

Load and validate configuration:

import yaml

def load_config(config_path):
    with open(config_path) as f:
        config = yaml.safe_load(f)
    validate_config(config)
    return config

Anti-Patterns to Avoid

❌ Don't: Swallow Exceptions

# BAD
try:
    do_something()
except:
    pass

✅ Do: Handle Explicitly

# GOOD
try:
    do_something()
except SpecificError as e:
    logger.warning(f"Expected error: {e}")
    return default_value

Category-Specific Patterns: General

Recommended Approach

1. Start with the simplest implementation 2. Add complexity only when needed 3. Test each addition 4. Document decisions

Common Integration Points

• Configuration: assets/config.yaml
• Validation: scripts/validate.py
• Documentation: references/GUIDE.md

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Pattern library for ethereum-development skill