W3Ship MCP Server

Instructions

Implementation Reference

• src/index.ts:742-836 (handler)

  The handler logic for 'get_swap_quote' tool, which fetches a quote from the Uniswap API.

  case 'get_swap_quote': {
      if (!UNISWAP_API_KEY) {
          return {
              content: [{ type: 'text', text: 'Error: UNISWAP_API_KEY environment variable is not set. Get your API key at https://developers.uniswap.org' }],
              isError: true,
          };
      }
  
      const { tokenIn: tokenInArg, tokenOut: tokenOutArg, amount: amountArg, walletAddress: swapWallet, chainId: swapChain } = args as any;
      const chainId = swapChain || 8453; // Default to Base
      const wallet = swapWallet || CONFIGURED_KEY;
  
      if (!wallet) {
          return {
              content: [{ type: 'text', text: 'Error: Wallet address required. Set W3SHIP_PUBLIC_KEY or provide walletAddress.' }],
              isError: true,
          };
      }
  
      // Resolve token symbols to addresses
      const resolveToken = (t: string) => {
          const upper = t.toUpperCase();
          return TOKENS[upper]?.address || t;
      };
      const resolveDecimals = (t: string) => {
          const upper = t.toUpperCase();
          return TOKENS[upper]?.decimals || 18;
      };
  
      const tokenInAddr = resolveToken(tokenInArg);
      const tokenOutAddr = resolveToken(tokenOutArg);
      const decimals = resolveDecimals(tokenInArg);
  
      // Convert human-readable amount to wei/smallest unit
      const amountRaw = BigInt(Math.floor(parseFloat(amountArg) * (10 ** decimals))).toString();
  
      try {
          const quoteRes = await fetch(`${UNISWAP_API}/quote`, {
              method: 'POST',
              headers: {
                  'Content-Type': 'application/json',
                  'x-api-key': UNISWAP_API_KEY,
              },
              body: JSON.stringify({
                  tokenIn: tokenInAddr,
                  tokenOut: tokenOutAddr,
                  amount: amountRaw,
                  type: 'EXACT_INPUT',
                  swapper: wallet,
                  tokenInChainId: chainId,
                  tokenOutChainId: chainId,
                  protocols: ['V2', 'V3', 'V4', 'UNISWAPX'],
              }),
          });
  
          const quoteData = await quoteRes.json() as any;
  
          if (!quoteRes.ok) {
              return {
                  content: [{ type: 'text', text: `Uniswap API error: ${quoteData.errorCode || quoteData.detail || JSON.stringify(quoteData)}` }],
                  isError: true,
              };
          }
  
          // Format output amount
          const outDecimals = resolveDecimals(tokenOutArg);
          const outputRaw = BigInt(quoteData.quote?.amountOut || quoteData.amountOut || '0');
          const outputFormatted = (Number(outputRaw) / (10 ** outDecimals)).toFixed(6);
  
          return {
              content: [{
                  type: 'text',
                  text: JSON.stringify({
                      quote: {
                          tokenIn: tokenInArg.toUpperCase(),
                          tokenOut: tokenOutArg.toUpperCase(),
                          amountIn: amountArg,
                          amountOut: outputFormatted,
                          chainId,
                          gasEstimate: quoteData.quote?.gasEstimate || quoteData.gasEstimate || 'N/A',
                          priceImpact: quoteData.quote?.priceImpact || quoteData.priceImpact || 'N/A',
                          routingPath: quoteData.quote?.route || quoteData.route || [],
                      },
                      message: `Swap ${amountArg} ${tokenInArg.toUpperCase()} → ${outputFormatted} ${tokenOutArg.toUpperCase()} on chain ${chainId}`,
                      needsApproval: quoteData.permit2 ? true : false,
                  }, null, 2)
              }]
          };
      } catch (e: any) {
          return {
              content: [{ type: 'text', text: `Error getting swap quote: ${e.message}` }],
              isError: true,
          };
      }
  }