Defi Protocol Templates

When to use this skill

Use Defi Protocol Templates when an AI agent needs a reusable SKILL.md workflow for this job: Implement DeFi protocols with production-ready templates for staking, AMMs, governance, and flash loans. Use when building decentralized finance applications or smart contract protocols.

When not to use it

Skip Defi Protocol Templates when the task is outside the creativity category, or when a more specific skill in this directory already covers the same workflow with clearer triggers.

How to install

1. Personal install: create ~/.claude/skills/defi-protocol-templates/SKILL.md (and any bundled scripts) so Claude Code, Claude Desktop, and compatible agents can load it in every project.
2. Project install: commit the same folder at .claude/skills/defi-protocol-templates/ so teammates get the skill with the repo.
3. Restart the agent session after copying files so it re-scans the skills directory, then ask for the task in words that match the skill description.

Full install guide for Claude, Cursor, and Codex

What this skill does

# DeFi Protocol Templates

Production-ready templates for common DeFi protocols including staking, AMMs, governance, and flash loans.

## When to Use This Skill

- Building staking platforms with reward distribution - Implementing AMM (Automated Market Maker) protocols - Creating governance token systems - Integrating flash loan functionality

## Staking Contract

```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol"; import "@openzeppelin/contracts/security/ReentrancyGuard.sol"; import "@openzeppelin/contracts/access/Ownable.sol";

contract StakingRewards is ReentrancyGuard, Ownable { IERC20 public stakingToken; IERC20 public rewardsToken;

uint256 public rewardRate = 100; // Rewards per second uint256 public lastUpdateTime; uint256 public rewardPerTokenStored;

mapping(address => uint256) public userRewardPerTokenPaid; mapping(address => uint256) public rewards; mapping(address => uint256) public balances;

uint256 private _totalSupply;

event Staked(address indexed user, uint256 amount); event Withdrawn(address indexed user, uint256 amount); event RewardPaid(address indexed user, uint256 reward);

constructor(address _stakingToken, address _rewardsToken) { stakingToken = IERC20(_stakingToken); rewardsToken = IERC20(_rewardsToken); }

modifier updateReward(address account) { rewardPerTokenStored = rewardPerToken(); lastUpdateTime = block.timestamp;

if (account != address(0)) { rewards[account] = earned(account); userRewardPerTokenPaid[account] = rewardPerTokenStored; } _; }

function rewardPerToken() public view returns (uint256) { if (_totalSupply == 0) { return rewardPerTokenStored; } return rewardPerTokenStored + ((block.timestamp - lastUpdateTime) * rewardRate * 1e18) / _totalSupply; }

function earned(address account) public view returns (uint256) { return (balances[account] * (rewardPerToken() - userRewardPerTokenPaid[account])) / 1e18 + rewards[account]; }

function stake(uint256 amount) external nonReentrant updateReward(msg.sender) { require(amount > 0, "Cannot stake 0"); _totalSupply += amount; balances[msg.sender] += amount; stakingToken.transferFrom(msg.sender, address(this), amount); emit Staked(msg.sender, amount); }

function withdraw(uint256 amount) public nonReentrant updateReward(msg.sender) { require(amount > 0, "Cannot withdraw 0"); _totalSupply -= amount; balances[msg.sender] -= amount; stakingToken.transfer(msg.sender, amount); emit Withdrawn(msg.sender, amount); }

function getReward() public nonReentrant updateReward(msg.sender) { uint256 reward = rewards[msg.sender]; if (reward > 0) { rewards[msg.sender] = 0; rewardsToken.transfer(msg.sender, reward); emit RewardPaid(msg.sender, reward); } }

function exit() external { withdraw(balances[msg.sender]); getReward(); } } ```

## AMM (Automated Market Maker)

```solidity // SPDX-License-Identifier: MIT pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract SimpleAMM { IERC20 public token0; IERC20 public token1;

uint256 public reserve0; uint256 public reserve1;

uint256 public totalSupply; mapping(address => uint256) public balanceOf;

event Mint(address indexed to, uint256 amount); event Burn(address indexed from, uint256 amount); event Swap(address indexed trader, uint256 amount0In, uint256 amount1In, uint256 amount0Out, uint256 amount1Out);

constructor(address _token0, address _token1) { token0 = IERC20(_token0); token1 = IERC20(_token1); }

function addLiquidity(uint256 amount0, uint256 amount1) external returns (uint256 shares) { token0.transferFrom(msg.sender, address(this), amount0); token1.transferFrom(msg.sender, address(this), amount1);

if (totalSupply == 0) { shares = sqrt(amount0 * amount1); } else { shares = min( (amount0 * totalSupply) / reserve0, (amount1 * totalSupply) / reserve1 ); }

require(shares > 0, "Shares = 0"); _mint(msg.sender, shares); _update( token0.balanceOf(address(this)), token1.balanceOf(address(this)) );

emit Mint(msg.sender, shares); }

function removeLiquidity(uint256 shares) external returns (uint256 amount0, uint256 amount1) { uint256 bal0 = token0.balanceOf(address(this)); uint256 bal1 = token1.balanceOf(address(this));

amount0 = (shares * bal0) / totalSupply; amount1 = (shares * bal1) / totalSupply;

require(amount0 > 0 && amount1 > 0, "Amount0 or amount1 = 0");

_burn(msg.sender, shares); _update(bal0 - amount0, bal1 - amount1);

token0.transfer(msg.sender, amount0); token1.transfer(msg.sender, amount1);

emit Burn(msg.sender, shares); }

function swap(address tokenIn, uint256 amountIn) external returns (uint256 amountOut) { require(tokenIn == address(token0) || tokenIn == address(token1), "Invalid token");

bool isToken0 = tokenIn == address(token0); (IERC20 tokenIn_, IERC20 tokenOut, uint256 resIn, uint256 resOut) = isToken0 ? (token0, token1, reserve0, reserve1) : (token1, token0, reserve1, reserve0);

tokenIn_.transferFrom(msg.sender, address(this), amountIn);

// 0.3% fee uint256 amountInWithFee = (amountIn * 997) / 1000; amountOut = (resOut * amountInWithFee) / (resIn + amountInWithFee);

tokenOut.transfer(msg.sender, amountOut);

_update( token0.balanceOf(address(this)), token1.balanceOf(address(this)) );

emit Swap(msg.sender, isToken0 ? amountIn : 0, isToken0 ? 0 : amountIn, isToken0 ? 0 : amountOut, isToken0 ? amountOut : 0); }

function _mint(address to, uint256 amount) private { balanceOf[to] += amount; totalSupply += amount; }

function _burn(address from, uint256 amount) private { balanceOf[from] -= amount; totalSupply -= amount; }

function _update(uint256 res0, uint256 res1) private { reserve0 = res0; reserve1 = res1; }

function sqrt(uint256 y) private pure returns (uint256 z) { if (y > 3) { z = y; uint256 x = y / 2 + 1; while (x < z) { z = x; x = (y / x + x) / 2; } } else if (y != 0) { z = 1; } }

function min(uint256 x, uint256 y) private pure returns (uint256) { return x <= y ? x : y; } } ```

## Additional patterns and templates

More detailed templates and worked examples live in `references/details.md`. Read that file for the full pattern library.

Intended uses

• Building staking platforms with reward distribution
• Implementing AMM (Automated Market Maker) protocols
• Creating governance token systems
• Integrating flash loan functionality