Design Patterns MCP Server

{ "category": "DeFi Lending", "description": "DeFi Lending design patterns for blockchain and Web3 applications", "patterns": [ { "id": "algorithmic-stablecoin", "name": "Algorithmic Stablecoin Pattern", "category": "DeFi Lending", "description": "Capital-efficient stablecoins using algorithmic supply adjustments. Dual token model (stable + volatile).", "when_to_use": [ "Experimental stablecoins", "capital efficiency prioritized over safety" ], "benefits": [ "Capital efficient", "no collateral needed", "scalable" ], "drawbacks": [ "Death spiral risk (UST/LUNA)", "complex mechanisms", "stability challenges" ], "use_cases": [ "Seigniorage shares", "rebase tokens (high risk - see UST collapse)" ], "complexity": "Very High", "tags": [ "defi", "stablecoin", "algorithmic", "rebase", "high-risk" ], "examples": { "solidity": { "language": "solidity", "code": "// Dual token: stable (UST) + volatile (LUNA)\nfunction expandSupply(uint256 amount) external {\n if (price > 1.01e18) { // Above peg\n stableToken.mint(msg.sender, amount);\n volatileToken.burn(msg.sender, getVolatileAmount(amount));\n }\n}\n\nfunction contractSupply(uint256 amount) external {\n if (price < 0.99e18) { // Below peg\n stableToken.burn(msg.sender, amount);\n volatileToken.mint(msg.sender, getVolatileAmount(amount));\n }\n}" } } }, { "id": "auto-compounding", "name": "Auto-Compounding", "category": "DeFi Lending", "description": "Automated harvest and reinvestment of yields", "when_to_use": [ "Yield aggregators", "vault strategies", "gas optimization" ], "benefits": [ "Gas-efficient", "higher APY", "automated" ], "drawbacks": [ "Smart contract risk", "keeper dependency", "fees" ], "use_cases": [ "Yearn auto-compound", "Beefy vaults", "yield optimization" ], "complexity": "Medium", "tags": [ "defi", "yield", "auto-compound", "vault", "harvest" ], "examples": { "solidity": { "language": "solidity", "code": "// Auto-Compound: harvest + reinvest\nfunction harvest() external {\n uint256 rewards = rewardToken.balanceOf(address(this));\n rewardToken.approve(dex, rewards);\n uint256 newAssets = dex.swap(rewardToken, asset, rewards);\n _deposit(newAssets); // Reinvest\n emit Harvested(rewards, newAssets);\n}" } } }, { "id": "cdp-maker", "name": "Collateralized Debt Position (CDP)", "category": "DeFi Lending", "description": "Lock collateral to mint stablecoin (MakerDAO model)", "when_to_use": [ "Decentralized stablecoin creation", "DAI minting" ], "benefits": [ "Decentralized", "over-collateralized secure" ], "drawbacks": [ "Capital inefficient", "liquidation risk", "complex governance" ], "use_cases": [ "DAI generation", "stablecoin protocols", "collateralized debt" ], "complexity": "High", "tags": [ "defi", "stablecoin", "makerdao", "cdp", "dai" ], "examples": { "solidity": { "language": "solidity", "code": "// CDP: lock collateral, mint DAI\nfunction openVault(uint256 ethAmount) external payable {\n require(msg.value == ethAmount);\n vaults[msg.sender].collateral += ethAmount;\n}\n\nfunction mintDAI(uint256 amount) external {\n uint256 maxDebt = vaults[msg.sender].collateral * RATIO / 100;\n require(vaults[msg.sender].debt + amount <= maxDebt);\n dai.mint(msg.sender, amount);\n}" } } }, { "id": "erc4626-vault", "name": "ERC-4626 Tokenized Vault", "category": "DeFi Lending", "description": "Standard vault interface for yield-bearing tokens", "when_to_use": [ "Yield vaults", "strategy vaults", "composable DeFi" ], "benefits": [ "Composability", "standardization", "tooling ecosystem" ], "drawbacks": [ "Still evolving", "integration overhead" ], "use_cases": [ "Yearn vaults", "strategy execution", "standardized yields" ], "complexity": "Medium", "tags": [ "defi", "vault", "erc4626", "yield", "standard" ], "examples": { "solidity": { "language": "solidity", "code": "// ERC-4626: standard vault\nimport \"@openzeppelin/contracts/token/ERC20/extensions/ERC4626.sol\";\n\ncontract YieldVault is ERC4626 {\n function totalAssets() public view override returns (uint256) {\n return asset.balanceOf(address(this)) + deployed;\n }\n}" } } }, { "id": "flash-loan", "name": "Flash Loan", "category": "DeFi Lending", "description": "Uncollateralized loan repaid in same transaction Problem: Need capital without upfront collateral", "when_to_use": [ "Loan and repayment atomic", "reverts if not repaid" ], "benefits": [ "No capital needed", "instant liquidity", "atomic" ], "drawbacks": [ "Same-transaction repayment", "complex logic", "exploit risk" ], "use_cases": [ "Arbitrage", "collateral swaps", "liquidations", "refinancing" ], "complexity": "High", "tags": [ "defi", "flash-loan", "lending", "arbitrage", "aave" ], "examples": { "solidity": { "language": "solidity", "code": "interface IFlashLoanReceiver {\n function executeOperation(\n address[] calldata assets,\n uint256[] calldata amounts,\n uint256[] calldata premiums,\n bytes calldata params\n ) external returns (bool);\n}" } } }, { "id": "hybrid-stablecoin-frax", "name": "Hybrid Stablecoin (Frax)", "category": "DeFi Lending", "description": "Partially collateralized stablecoin. Balance between full collateral and algorithmic.", "when_to_use": [ "Stablecoins seeking balance between capital efficiency and stability" ], "benefits": [ "More capital efficient than fully collateralized", "more stable than algorithmic" ], "drawbacks": [ "Complex mechanism", "still has stability risks", "governance dependency" ], "use_cases": [ "FRAX (fractional reserves)", "hybrid collateral models" ], "complexity": "Very High", "tags": [ "defi", "stablecoin", "frax", "hybrid", "fractional-reserve" ], "examples": { "solidity": { "language": "solidity", "code": "// Fractional reserve model (e.g., 85% USDC, 15% FXS)\nfunction mint(uint256 fraxAmount) external {\n uint256 collateralRatio = getCollateralRatio(); // e.g., 85%\n uint256 collateralNeeded = (fraxAmount * collateralRatio) / 1e6;\n uint256 fxsToBurn = (fraxAmount * (1e6 - collateralRatio)) / 1e6;\n \n usdc.transferFrom(msg.sender, address(this), collateralNeeded);\n fxs.burn(msg.sender, fxsToBurn);\n frax.mint(msg.sender, fraxAmount);\n}" } } }, { "id": "interest-rate-model", "name": "Interest Rate Model", "category": "DeFi Lending", "description": "Dynamic rates based on utilization with kink mechanism", "when_to_use": [ "All lending protocols", "borrow/supply rate calculation" ], "benefits": [ "Market-driven", "incentivizes balance", "automatic adjustment" ], "drawbacks": [ "Can spike during high demand", "complex parameters" ], "use_cases": [ "Aave rates", "Compound rates", "optimal utilization" ], "complexity": "Medium", "tags": [ "defi", "lending", "interest-rates", "utilization" ], "examples": { "solidity": { "language": "solidity", "code": "// Interest Rate: kink model\nfunction getBorrowRate(uint256 utilization) public view returns (uint256) {\n if (utilization <= KINK) {\n return BASE_RATE + utilization * SLOPE1 / 1e18;\n } else {\n return BASE_RATE + KINK * SLOPE1 / 1e18 +\n (utilization - KINK) * SLOPE2 / 1e18;\n }\n}" } } }, { "id": "liquid-restaking-lrt", "name": "Liquid Restaking Token (LRT)", "category": "DeFi Lending", "description": "Liquidity for restaked positions via wrapped tokens. Composable restaking, DeFi integration.", "when_to_use": [ "Liquidity while restaking", "DeFi composability", "yield optimization" ], "benefits": [ "Liquidity while restaking", "composable in DeFi", "additional yield layers" ], "drawbacks": [ "Smart contract risk", "de-pegging risk", "complexity stacking" ], "use_cases": [ "ether.fi eETH", "Puffer Finance", "Renzo ezETH" ], "complexity": "Very High", "tags": [ "restaking", "lrt", "liquidity", "defi", "eigenlayer" ], "examples": { "solidity": { "language": "solidity", "code": "contract LiquidRestakingToken is ERC20 {\n IEigenLayer public eigenLayer;\n \n function deposit() external payable {\n // 1. Stake ETH to beacon chain\n beaconChain.stake{value: msg.value}();\n \n // 2. Restake via EigenLayer\n eigenLayer.depositBeaconChainETH(msg.sender, msg.value);\n \n // 3. Mint liquid token (eETH, ezETH, etc.)\n uint256 shares = (msg.value * totalSupply()) / getTotalPooledEther();\n _mint(msg.sender, shares);\n }\n \n // Users can use LRT in DeFi while earning:\n // - Beacon chain rewards\n // - EigenLayer restaking rewards \n // - AVS rewards\n}" } } }, { "id": "liquidation-mechanism", "name": "Liquidation Mechanism", "category": "DeFi Lending", "description": "Automated liquidation to maintain protocol solvency with liquidator incentives", "when_to_use": [ "All collateralized lending", "maintain solvency" ], "benefits": [ "Protects lenders", "incentivizes liquidators", "automatic" ], "drawbacks": [ "Can cascade", "user loss", "gas wars" ], "use_cases": [ "Aave liquidations", "Compound liquidations", "MEV" ], "complexity": "High", "tags": [ "defi", "lending", "liquidation", "mev", "incentives" ], "examples": { "solidity": { "language": "solidity", "code": "// Liquidation: discount for liquidators\nfunction liquidate(address borrower, address collateral) external {\n require(isLiquidatable(borrower));\n uint256 debt = getUserDebt(borrower);\n uint256 collateralSeized = debt * LIQUIDATION_BONUS / 100;\n _transfer(collateral, msg.sender, collateralSeized);\n}" } } }, { "id": "native-restaking-eigenlayer", "name": "Native Restaking (EigenLayer)", "category": "DeFi Lending", "description": "Reuse staked ETH to secure additional protocols (AVS). Earn additional yields, share security.", "when_to_use": [ "Capital efficiency", "securing AVSs", "increased ETH yields" ], "benefits": [ "Capital efficient", "shared security", "$20B+ TVL", "additional yields" ], "drawbacks": [ "Increased slashing risk", "complexity", "protocol dependencies" ], "use_cases": [ "EigenLayer AVS", "additional protocol security", "yield enhancement" ], "complexity": "Very High", "tags": [ "restaking", "eigenlayer", "eth", "avs", "capital-efficiency" ], "examples": { "solidity": { "language": "solidity", "code": "// EigenLayer restaking\ncontract EigenPodManager {\n mapping(address => IEigenPod) public pods;\n \n function createPod() external returns (address) {\n IEigenPod pod = IEigenPod(Create2.deploy(podImplementation));\n pods[msg.sender] = pod;\n return address(pod);\n }\n \n function verifyWithdrawalCredentials(...) external {\n // Verify ETH is staked and withdrawal creds point to EigenPod\n // Now ETH is restakable to secure AVSs\n }\n}\n\n// Opt into AVS (Actively Validated Service)\nfunction optIntoAVS(address avs) external {\n require(hasMinimumStake(msg.sender));\n avsDirectory.registerOperator(msg.sender, avs);\n // Now securing AVS, earning additional rewards, subject to AVS slashing\n}" } } }, { "id": "over-collateralized-lending", "name": "Over-Collateralized Lending", "category": "DeFi Lending", "description": "Trustless lending requiring >100% collateral (Aave/Compound model)", "when_to_use": [ "DeFi lending protocols", "margin trading", "liquidity without selling" ], "benefits": [ "No counterparty risk", "instant liquidity", "trustless" ], "drawbacks": [ "Capital inefficient", "liquidation risk", "over-collateralization" ], "use_cases": [ "Borrowing stablecoins", "leveraged positions", "yield farming" ], "complexity": "Medium", "tags": [ "defi", "lending", "aave", "compound", "collateral" ], "examples": { "solidity": { "language": "solidity", "code": "// Over-Collateralized Lending\nfunction borrow(address asset, uint256 amount) external {\n uint256 collateralValue = getUserCollateralValue(msg.sender);\n uint256 borrowValue = amount * getPrice(asset);\n require(collateralValue * LTV / 100 >= borrowValue);\n _transfer(asset, msg.sender, amount);\n}" } } }, { "id": "staking-rewards", "name": "Staking Rewards", "category": "DeFi Lending", "description": "Proportional rewards for token staking Problem: Incentivize token locking and participation", "when_to_use": [ "Rewards proportional to stake and time" ], "benefits": [ "Simple incentive", "effective for bootstrapping" ], "drawbacks": [ "Sell pressure", "complex reward math", "sustainability" ], "use_cases": [ "Governance", "liquidity mining", "yield farming" ], "complexity": "Medium", "tags": [ "defi", "staking", "rewards", "yield", "liquidity-mining" ], "examples": { "solidity": { "language": "solidity", "code": "uint256 public rewardPerTokenStored;\nmapping(address => uint256) public userRewardPerTokenPaid;\n\nfunction earned(address account) public view returns (uint256) {\n return balances[account] * \n (rewardPerTokenStored - userRewardPerTokenPaid[account]);\n}" } } }, { "id": "strategy-vault-yearn", "name": "Strategy Vault (Yearn)", "category": "DeFi Lending", "description": "Automated yield optimization with pluggable strategies. Vault manages capital, strategies execute.", "when_to_use": [ "Yield optimization", "automated strategy execution", "capital pooling" ], "benefits": [ "Automated", "gas-efficient for users", "expert strategies", "composable" ], "drawbacks": [ "Smart contract risk", "strategy risk", "complexity" ], "use_cases": [ "Yearn vaults", "automated yield farming", "strategy aggregation" ], "complexity": "High", "tags": [ "defi", "vault", "yearn", "strategy", "yield-optimization" ], "examples": { "solidity": { "language": "solidity", "code": "contract Vault {\n IStrategy public strategy;\n \n function deposit(uint256 amount) external {\n token.transferFrom(msg.sender, address(this), amount);\n uint256 shares = (amount * totalSupply) / totalAssets();\n _mint(msg.sender, shares);\n token.transfer(address(strategy), amount);\n strategy.invest(amount);\n }\n \n function harvest() external {\n strategy.harvest(); // Execute strategy, collect rewards\n }\n}" } } } ] }