YNAB MCP Server

Instructions

Implementation Reference

• src/index.ts:102-104 (handler)

  The core function that executes the tool logic by fetching scheduled transactions from the YNAB API.

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

• src/index.ts:373-377 (handler)

  The server-side handler case that validates input and calls the client method to execute the tool.

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

• src/index.ts:256-266 (registration)

  Registers the tool in the tools array provided to the MCP server.

  {
    name: "list_scheduled_transactions",
    description: "Get all scheduled/recurring transactions for a budget.",
    inputSchema: {
      type: "object" as const,
      properties: {
        budget_id: { type: "string", description: "The budget ID" },
      },
      required: ["budget_id"],
    },
  },

• src/index.ts:116-118 (schema)

  Zod schema for input validation used in the tool handler.

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