Skill: wagmi

Scope

• React/Next.js wallet integration with Wagmi v3 for EVM chains
• Contract interactions using viem v2 for address validation and transaction building
• Transaction state management and error handling
• Custom hooks wrapping wagmi for contract-specific interactions

Does NOT cover:

• Solana frontend development
• Backend RPC interactions
• Smart contract development

Assumptions

• Wagmi v3.3.2+
• viem v2.44.4
• React 18+ or Next.js 14+
• TypeScript v5+ with strict mode
• TanStack Query v5+ (peer dependency of wagmi)
• WalletConnect v2+ (optional, for WalletConnect connector)

Principles

• Use Wagmi v3.x hooks for wallet state (useAccount, useWriteContract, useReadContract, useWaitForTransactionReceipt, useSimulateContract)
• Use viem v2 for address validation (getAddress) and transaction utilities (parseEther, parseGwei)
• Create custom hooks wrapping wagmi for contract-specific interactions
• Handle connection states explicitly: disconnected, connecting, connected, reconnecting
• Validate addresses with getAddress() from viem before use (never cast directly as Address)
• Use generated contract ABIs and types from OpenAPI specs
• Use TanStack Query (via wagmi) for caching and refetching contract data
• Simulate contracts before writing to validate and estimate gas
• Use conditional queries with enabled flags to prevent unnecessary fetches
• Handle SSR properly with cookie storage for persistent wallet state

Constraints

MUST

• Use Wagmi v3.x (not v1 or v2) - v1/v2 patterns are incompatible
• Validate addresses with getAddress() from viem - never cast strings directly
• Handle SSR properly in Next.js (use dynamic with ssr: false for wallet components)

SHOULD

• Create custom hooks for contract interactions
• Simulate contracts before writing (useSimulateContract)
• Use conditional queries with enabled flags
• Use cookie storage for SSR persistence
• Handle all connection states explicitly

AVOID

• Wrapping generated hooks from OpenAPI clients unless necessary for abstraction
• Exposing private keys or sensitive wallet data in components
• Skipping address validation

Interactions

• Uses generated contract ABIs/types from OpenAPI specs
• Complements fastify for API development

Patterns and code samples: PATTERNS.md.