NWC MCP Server

Instructions

Implementation Reference

• src/tools/make_invoice.ts:31-47 (handler)

  The handler function that creates a Lightning invoice using the NWC client and returns the result as formatted text content.

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

• src/tools/make_invoice.ts:12-30 (schema)

  Zod schema defining the input parameters for the make_invoice tool, including amount, expiry, description, etc.

  {
    amount: z.number().describe("amount in millisats"),
    expiry: z.number().describe("expiry in seconds").nullish(),
    description: z
      .string()
      .describe("note, memo or description describing the invoice")
      .nullish(),
    description_hash: z
      .string()
      .describe(
        "hash of a note, memo or description that is too long to fit within the invoice"
      )
      .nullish(),
    metadata: z
      .object({})
      .passthrough()
      .describe("Optional metadata to include with the payment")
      .nullish(),
  },

• src/tools/make_invoice.ts:5-49 (registration)

  The registerMakeInvoiceTool function that registers the make_invoice tool with the MCP server, including name, description, schema, and handler.

  export function registerMakeInvoiceTool(
    server: McpServer,
    client: nwc.NWCClient
  ) {
    server.tool(
      "make_invoice",
      "Create a lightning invoice",
      {
        amount: z.number().describe("amount in millisats"),
        expiry: z.number().describe("expiry in seconds").nullish(),
        description: z
          .string()
          .describe("note, memo or description describing the invoice")
          .nullish(),
        description_hash: z
          .string()
          .describe(
            "hash of a note, memo or description that is too long to fit within the invoice"
          )
          .nullish(),
        metadata: z
          .object({})
          .passthrough()
          .describe("Optional metadata to include with the payment")
          .nullish(),
      },
      async (params) => {
        const result = await client.makeInvoice({
          amount: params.amount,
          description: params.description || undefined,
          description_hash: params.description_hash || undefined,
          expiry: params.expiry || undefined,
          metadata: params.metadata || undefined,
        });
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(result, null, 2),
            },
          ],
        };
      }
    );
  }

• src/mcp_server.ts:21-21 (registration)

  Call to registerMakeInvoiceTool during MCP server creation, integrating the make_invoice tool.

  registerMakeInvoiceTool(server, client);