vechain Smart Contract Development Skill
CRITICAL RULES
- Read reference files FIRST. When the user's request involves any topic in the reference table below, read those files before doing anything else — before writing code, before making decisions. Briefly mention which files you are reading so the user can confirm the skill is active (e.g., "Reading smart contracts reference...").
- Information priority for VeChain topics: (a) Reference files in this skill — always the primary source. (b) VeChain MCP tools — use
@vechain/mcp-serverfor on-chain data, transaction building, and live network queries; use Kapa AI MCP for VeChain documentation lookups. (c) Web search — only as a last resort, and only for topics NOT covered in the reference files. - Prefer working directly in the main conversation for VeChain tasks. Plan mode and subagents do not inherit skill context and may fall back to web search instead of using reference files.
- After compaction or context loss, re-read this SKILL.md to restore awareness of the reference table and operating procedure before continuing work.
Scope
Use this Skill for Solidity smart contract development on VeChainThor:
- Solidity contracts with Hardhat +
@vechain/sdk-hardhat-plugin - ERC-20, ERC-721, access control, upgradeable (UUPS) patterns
- Gas optimization techniques
- Testing with Hardhat + Thor Solo
- Security reviews and audit checklists
- ABI codegen and TypeChain setup
Default stack
| Layer | Default | Alternative |
|---|---|---|
| Contracts | Solidity + Hardhat + @vechain/sdk-hardhat-plugin |
-- |
| EVM target | paris (mandatory) |
-- |
| Testing | Hardhat + Thor Solo (--on-demand) |
-- |
| Types | TypeChain (@typechain/ethers-v6) |
@vechain/vechain-contract-types (pre-built) |
| Node | Node 20 LTS (managed via nvm) |
-- |
Operating procedure
1. Check Node version
Before installing dependencies or running any command:
- Check if
.nvmrcexists in the project root. If yes, runnvm useto switch to the required version. - If
.nvmrcdoes not exist, create one with20(Node 20 LTS) and runnvm use.
2. Detect project structure
turbo.jsonpresent → follow Turborepo conventions (packages/contracts,packages/*)
3. Clarify before implementing
When the user's request is ambiguous or could be solved multiple ways, ask before building. Separate research from implementation.
4. Implement with VeChain-specific correctness
- Network: always explicit (
mainnet/testnet/solo) - EVM target: always
paris - Gas: estimate first
- Tokens: VET for value, VTHO for gas (dual-token model)
5. Verify and deliver
A task is not complete until all applicable gates pass:
- Code compiles — no build errors
- Tests pass — existing tests still pass; new logic has test coverage
- Risk notes documented — any signing, fee, or token-transfer implications are called out
Reference files
Read the matching files BEFORE doing anything else. See Critical Rules above.
| Topic | File | Read when user mentions... |
|---|---|---|
| Smart contracts | references/smart-contracts.md | Solidity, Hardhat, ERC-20, ERC-721, deploy, contract interaction, libraries, contract size, upgradeable, proxy, upgrade, reinitializer, version pattern, deploy helpers, NatSpec, Slither |
| Gas optimization | references/smart-contracts-optimization.md | gas, optimize, storage packing, assembly, unchecked |
| Testing | references/testing.md | test, Thor Solo, Docker, CI, fixtures |
| ABI / codegen | references/abi-codegen.md | TypeChain, ABI, typechain-types, code generation |
| Security | references/security.md | security, audit, vulnerability, reentrancy, access control, invariant, balance check, path symmetry, adversarial, edge cases, what could go wrong |