NWC MCP Server

Instructions

Implementation Reference

• src/tools/pay_invoice.ts:24-39 (handler)

  The asynchronous handler function that executes the pay_invoice tool logic: calls client.payInvoice with the input parameters and returns the result as a text content block with JSON stringified response.

    async (params) => {
      const result = await client.payInvoice({
        invoice: params.invoice,
        amount: params.amount || undefined,
        metadata: params.metadata || undefined,
      });
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(result, null, 2),
          },
        ],
      };
    }
  );

• src/tools/pay_invoice.ts:12-23 (schema)

  Zod schema for input parameters of the pay_invoice tool: required 'invoice' string, optional 'amount' number in millisats, optional 'metadata' passthrough object.

  {
    invoice: z.string().describe("The lightning invoice to pay"),
    amount: z
      .number()
      .describe("Optional amount in millisats to pay a zero-amount invoice")
      .nullish(),
    metadata: z
      .object({})
      .passthrough()
      .describe("Optional metadata to include with the payment")
      .nullish(),
  },

• src/tools/pay_invoice.ts:5-40 (registration)

  The registerPayInvoiceTool function exports the registration logic, calling server.tool to register the 'pay_invoice' tool with its schema and handler.

  export function registerPayInvoiceTool(
    server: McpServer,
    client: nwc.NWCClient
  ) {
    server.tool(
      "pay_invoice",
      "Pay a lightning invoice",
      {
        invoice: z.string().describe("The lightning invoice to pay"),
        amount: z
          .number()
          .describe("Optional amount in millisats to pay a zero-amount invoice")
          .nullish(),
        metadata: z
          .object({})
          .passthrough()
          .describe("Optional metadata to include with the payment")
          .nullish(),
      },
      async (params) => {
        const result = await client.payInvoice({
          invoice: params.invoice,
          amount: params.amount || undefined,
          metadata: params.metadata || undefined,
        });
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(result, null, 2),
            },
          ],
        };
      }
    );
  }

• src/mcp_server.ts:22-22 (registration)

  Invocation of registerPayInvoiceTool within createMCPServer to register the pay_invoice tool on the MCP server instance.

  registerPayInvoiceTool(server, client);

• src/mcp_server.ts:7-7 (registration)

  Import of the registerPayInvoiceTool function from the pay_invoice module.

  import { registerPayInvoiceTool } from "./tools/pay_invoice.js";