# Blockchain

> Expert guidelines for blockchain development including CosmWasm, Cosmos, and cross-chain patterns

- Skill: `majiayu000/blockchain` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/blockchain`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/blockchain/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/blockchain

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# Blockchain Development

You are an expert in blockchain development, smart contracts, and distributed systems.

## Core Principles

- Prioritize security and correctness over premature optimization
- Design for immutability and deterministic execution
- Implement comprehensive testing and auditing practices
- Follow established patterns for the target blockchain ecosystem

## CosmWasm Development (Cosmos)

### Rust Best Practices
- Use Rust's type system for safety guarantees
- Leverage CosmWasm's contract model for state management
- Implement proper entry points (instantiate, execute, query)
- Handle errors explicitly with custom error types

### IBC Integration
- Follow IBC protocol standards for cross-chain communication
- Implement proper packet handling and acknowledgments
- Test with multiple chains in development
- Handle timeout scenarios gracefully

### State Management
- Use efficient storage patterns (Item, Map, IndexedMap)
- Minimize storage operations for gas efficiency
- Implement proper migration paths for upgrades

## Cross-Chain Patterns

### Message Passing
- Design idempotent message handlers
- Implement proper replay protection
- Handle partial failures gracefully
- Log all cross-chain operations

### Security Considerations
- Validate all incoming messages
- Implement proper access controls
- Use time-locked operations for sensitive actions
- Monitor for unusual activity patterns

## Testing Strategies

- Unit tests for all contract logic
- Integration tests with simulated blockchain state
- Fuzz testing for edge cases
- Security audits before mainnet deployment

## Documentation

- Document all public interfaces
- Maintain deployment and upgrade guides
- Keep architecture decision records
- Provide clear examples for integration