YNAB MCP Server

Instructions

Implementation Reference

• src/index.ts:98-100 (handler)

  The core handler function in the YNABClient class that fetches the list of payees for a given budget ID from the YNAB API.

  async listPayees(budgetId: string) {
    return this.request<{ payees: any[] }>(`/budgets/${budgetId}/payees`);
  }

• src/index.ts:116-118 (schema)

  Zod schema for validating the budget_id input parameter used in the list_payees tool.

  const BudgetIdSchema = z.object({
    budget_id: z.string().describe("The budget ID (use 'last-used' for most recent)"),
  });

• src/index.ts:245-255 (registration)

  The tool registration object defining the name, description, and JSON input schema for the 'list_payees' tool in the list of available tools.

  {
    name: "list_payees",
    description: "Get all payees for a budget.",
    inputSchema: {
      type: "object" as const,
      properties: {
        budget_id: { type: "string", description: "The budget ID" },
      },
      required: ["budget_id"],
    },
  },

• src/index.ts:367-371 (handler)

  The switch case in the MCP CallToolRequest handler that parses arguments using BudgetIdSchema and calls the listPayees method.

  case "list_payees": {
    const { budget_id } = BudgetIdSchema.parse(args);
    result = await client.listPayees(budget_id);
    break;
  }