MCPilot

Instructions

Implementation Reference

• packages/metamask-mcp/src/tools/call.ts:17-57 (handler)

  Handler function that executes the low-level 'call' action using wagmi/core's call, casting arguments, handling TransactionExecutionError and generic errors, returning JSON-stringified result or error message.

  execute: async (args) => {
    try {
      const to = args.to as Address
      const value = args.value ? BigInt(args.value) : undefined
      const data = args.data as Address
      const result = await call(wagmiConfig, {
        to,
        value,
        data,
      })
      return {
        content: [
          {
            type: "text",
            text: JSONStringify({
              hash: result
            }),
          },
        ],
      }
    } catch (error) {
      if (error instanceof TransactionExecutionError) {
        return {
          content: [
            {
              type: "text",
              text: error.cause.message,
            }
          ]
        }
      }
      return {
        content: [
          {
            type: "text",
            text: (error as Error).message,
          }
        ]
      }
    }
  },

• packages/metamask-mcp/src/tools/call.ts:12-16 (schema)

  Zod input schema for the 'call' tool defining parameters: to (string address), optional value (number coerced to bigint), data (string calldata).

  parameters: z.object({
    to: z.string(),
    value: z.coerce.number().optional(),
    data: z.string(),
  }),

• packages/metamask-mcp/src/tools/call.ts:9-58 (registration)

  Core registration of the 'call' tool on the FastMCP server within registerCallTools, including name, description, schema, and handler.

  server.addTool({
    name: "call",
    description: "Executing a new message call immediately without submitting a transaction to the network",
    parameters: z.object({
      to: z.string(),
      value: z.coerce.number().optional(),
      data: z.string(),
    }),
    execute: async (args) => {
      try {
        const to = args.to as Address
        const value = args.value ? BigInt(args.value) : undefined
        const data = args.data as Address
        const result = await call(wagmiConfig, {
          to,
          value,
          data,
        })
        return {
          content: [
            {
              type: "text",
              text: JSONStringify({
                hash: result
              }),
            },
          ],
        }
      } catch (error) {
        if (error instanceof TransactionExecutionError) {
          return {
            content: [
              {
                type: "text",
                text: error.cause.message,
              }
            ]
          }
        }
        return {
          content: [
            {
              type: "text",
              text: (error as Error).message,
            }
          ]
        }
      }
    },
  });

• packages/metamask-mcp/src/index.ts:39-39 (registration)

  Invocation of the registerCallTools function on the main FastMCP server instance to register the 'call' tool.

  registerCallTools(server);