name: crane-camelot description: This skill should be used when the user asks about "Camelot integration", "Camelot swap", "Camelot liquidity", "Camelot V2", "fee-on-transfer tokens", "asymmetric fees", "directional fees", or needs to interact with Camelot DEX on Arbitrum using Crane's service library. license: MIT

Crane Camelot V2 Integration

Crane provides Camelot V2 integration with service library, stubs, and test infrastructure. Camelot differs from standard Uniswap V2 forks by supporting asymmetric (directional) fees.

Components

Key Difference: Asymmetric Fees

Camelot pools have directional fees - different fees for each swap direction:

// Camelot's getReserves returns fees for each direction
(uint112 reserve0, uint112 reserve1, uint16 token0feePercent, uint16 token1FeePercent) = pool.getReserves();

// token0feePercent: Fee when swapping token0 -> token1
// token1FeePercent: Fee when swapping token1 -> token0

Quick Start: Execute Swap

import {CamelotV2Service} from "@crane/contracts/protocols/dexes/camelot/v2/services/CamelotV2Service.sol";
import {ICamelotV2Router} from "@crane/contracts/interfaces/protocols/dexes/camelot/v2/ICamelotV2Router.sol";
import {ICamelotPair} from "@crane/contracts/interfaces/protocols/dexes/camelot/v2/ICamelotPair.sol";

contract CamelotSwapper {
    ICamelotV2Router public router;

    function swap(
        ICamelotPair pool,
        IERC20 tokenIn,
        IERC20 tokenOut,
        uint256 amountIn
    ) external returns (uint256 amountOut) {
        tokenIn.transferFrom(msg.sender, address(this), amountIn);

        amountOut = CamelotV2Service._swap(
            router,
            pool,
            amountIn,
            tokenIn,
            tokenOut,
            address(0)  // referrer (optional)
        );
    }
}

Service Operations

Deposit (Add Liquidity)

function _deposit(
    ICamelotV2Router router,
    IERC20 tokenA,
    IERC20 tokenB,
    uint256 amountADesired,
    uint256 amountBDesired
) internal returns (uint256 liquidity);

Withdraw (Remove Liquidity)

// Direct withdrawal (no router)
function _withdrawDirect(
    ICamelotPair pool,
    uint256 amt
) internal returns (uint256 amount0, uint256 amount1);

Swap

// Swap with pool auto-detection
function _swap(
    ICamelotV2Router router,
    ICamelotPair pool,
    uint256 amountIn,
    IERC20 tokenIn,
    IERC20 tokenOut,
    address referrer
) internal returns (uint256 amountOut);

// Swap with explicit reserves and fees
function _swap(
    ICamelotV2Router router,
    uint256 amountIn,
    IERC20 tokenIn,
    uint256 reserveIn,
    uint256 feePercent,
    IERC20 tokenOut,
    uint256 reserveOut,
    address referrer
) internal returns (uint256 amountOut);

Swap and Deposit (Zap In)

function _swapDeposit(
    ICamelotV2Router router,
    ICamelotPair pool,
    IERC20 tokenIn,
    uint256 saleAmt,
    IERC20 opToken,
    address referrer
) internal returns (uint256 lpAmount);

Withdraw and Swap (Zap Out)

function _withdrawSwapDirect(
    ICamelotPair pool,
    ICamelotV2Router router,
    uint256 amt,
    IERC20 tokenOut,
    IERC20 opToken,
    address referrer
) internal returns (uint256 amountOut);

Reserve Sorting

Get reserves sorted by known token:

(
    uint256 knownReserve,
    uint256 opposingReserve,
    uint256 knownFeePercent,
    uint256 opposingFeePercent
) = CamelotV2Service._sortReserves(pool, knownToken);

Testing

import {TestBase_CamelotV2} from "@crane/contracts/protocols/dexes/camelot/v2/test/bases/TestBase_CamelotV2.sol";

contract MyTest is TestBase_CamelotV2 {
    function setUp() public override {
        super.setUp();
        // camelotV2Factory and camelotV2Router available
    }

    function test_swap() public {
        // Create pair
        address pair = camelotV2Factory.createPair(
            address(tokenA),
            address(tokenB)
        );

        // Add liquidity
        CamelotV2Service._deposit(
            camelotV2Router,
            tokenA,
            tokenB,
            1000e18,
            1000e18
        );

        // Execute swap
        uint256 amountOut = CamelotV2Service._swap(
            camelotV2Router,
            ICamelotPair(pair),
            100e18,
            tokenA,
            tokenB,
            address(0)
        );
    }
}

Fee-on-Transfer Token Support

Camelot uses swapExactTokensForTokensSupportingFeeOnTransferTokens to support deflationary tokens:

router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
    amountIn,
    amountOutMin,
    path,
    to,
    referrer,
    deadline
);

File Organization

contracts/protocols/dexes/camelot/v2/
├── services/
│   └── CamelotV2Service.sol
├── CamelotV2RouterAwareRepo.sol
├── CamelotV2FactoryAwareRepo.sol
├── stubs/
│   ├── CamelotFactory.sol
│   ├── CamelotRouter.sol
│   ├── CamelotPair.sol
│   └── libraries/
│       ├── Math.sol
│       ├── SafeMath.sol
│       └── UniswapV2Library.sol
└── test/bases/
    └── TestBase_CamelotV2.sol

Additional Resources

Reference Files

• references/camelot-services.md - Detailed patterns and examples