mcp-server

Instructions

Implementation Reference

• src/tools/write/wallet/approve.ts:12-104 (registration)

  The tool "write.wallet.approve" is registered and handled within this function.

  export function registerApproveTool(server: McpServer, _chains: Record<ChainId, ChainConfig>) {
    server.registerTool(
      "write.wallet.approve",
      {
        annotations: {
          title: "Build Approve Transaction",
          readOnlyHint: false,
          destructiveHint: false,
          idempotentHint: true,
          openWorldHint: false,
        },
        outputSchema: SimpleTransactionOutput,
        description:
          "Build an unsigned approval transaction. For ERC20 tokens: generates approve(spender, amount). For ERC721/ERC1155 NFTs (e.g. LP positions): generates setApprovalForAll(operator, true). Required before write.account.deposit or write.account.add_liquidity (when depositing from wallet). Tip: call read.wallet.allowances first to check if approval already exists — skip this if the current allowance is sufficient.",
        inputSchema: {
          token_address: z.string().describe("Token contract address to approve"),
          spender_address: z
            .string()
            .describe("Address being approved — use the Arcadia account address for deposits"),
          asset_type: z
            .enum(["erc20", "erc721", "erc1155"])
            .default("erc20")
            .describe(
              "Token type: 'erc20' (default) for fungible tokens, 'erc721' or 'erc1155' for NFTs (LP positions)",
            ),
          amount: z
            .string()
            .default("max_uint256")
            .describe(
              "ERC20 only: amount in raw units, or 'max_uint256' for unlimited. Ignored for NFTs.",
            ),
          chain_id: z.number().default(8453).describe("Chain ID: 8453 (Base) or 130 (Unichain)"),
        },
      },
      async (params) => {
        try {
          const validToken = validateAddress(params.token_address, "token_address");
          const validSpender = validateAddress(params.spender_address, "spender_address");
  
          let data: `0x${string}`;
          let description: string;
  
          if (params.asset_type === "erc721" || params.asset_type === "erc1155") {
            data = encodeFunctionData({
              abi: nftmanagerAbi,
              functionName: "setApprovalForAll",
              args: [validSpender, true],
            });
            description = `Approve ${params.spender_address} to transfer all ${params.asset_type.toUpperCase()} tokens from ${params.token_address}`;
          } else {
            const amount =
              !params.amount || params.amount === "max_uint256" ? MAX_UINT256 : BigInt(params.amount);
            data = encodeFunctionData({
              abi: erc20Abi,
              functionName: "approve",
              args: [validSpender, amount],
            });
            description = `Approve ${params.spender_address} to spend ${params.token_address}`;
          }
          data = appendDataSuffix(data) as `0x${string}`;
  
          const result = {
            description,
            transaction: {
              to: validToken,
              data,
              value: "0",
              chainId: params.chain_id,
            },
          };
          return {
            content: [
              {
                type: "text" as const,
                text: JSON.stringify(result, null, 2),
              },
            ],
            structuredContent: result,
          };
        } catch (err) {
          return {
            content: [
              {
                type: "text" as const,
                text: `Error: ${err instanceof Error ? err.message : String(err)}`,
              },
            ],
            isError: true,
          };
        }
      },
    );
  }

• src/tools/write/wallet/approve.ts:46-102 (handler)

  The tool handler implementation for "write.wallet.approve", which generates an approval transaction for ERC20, ERC721, or ERC1155 tokens.

  async (params) => {
    try {
      const validToken = validateAddress(params.token_address, "token_address");
      const validSpender = validateAddress(params.spender_address, "spender_address");
  
      let data: `0x${string}`;
      let description: string;
  
      if (params.asset_type === "erc721" || params.asset_type === "erc1155") {
        data = encodeFunctionData({
          abi: nftmanagerAbi,
          functionName: "setApprovalForAll",
          args: [validSpender, true],
        });
        description = `Approve ${params.spender_address} to transfer all ${params.asset_type.toUpperCase()} tokens from ${params.token_address}`;
      } else {
        const amount =
          !params.amount || params.amount === "max_uint256" ? MAX_UINT256 : BigInt(params.amount);
        data = encodeFunctionData({
          abi: erc20Abi,
          functionName: "approve",
          args: [validSpender, amount],
        });
        description = `Approve ${params.spender_address} to spend ${params.token_address}`;
      }
      data = appendDataSuffix(data) as `0x${string}`;
  
      const result = {
        description,
        transaction: {
          to: validToken,
          data,
          value: "0",
          chainId: params.chain_id,
        },
      };
      return {
        content: [
          {
            type: "text" as const,
            text: JSON.stringify(result, null, 2),
          },
        ],
        structuredContent: result,
      };
    } catch (err) {
      return {
        content: [
          {
            type: "text" as const,
            text: `Error: ${err instanceof Error ? err.message : String(err)}`,
          },
        ],
        isError: true,
      };
    }
  },