YNAB MCP Server

Instructions

Implementation Reference

• src/index.ts:41-43 (handler)

  The core handler function in the YNABClient class that fetches detailed budget information from the YNAB API using an HTTP request.

  async getBudget(budgetId: string) {
    return this.request<{ budget: any }>(`/budgets/${budgetId}`);
  }

• src/index.ts:319-323 (handler)

  The dispatch handler in the MCP CallToolRequestSchema that validates the input arguments and invokes the getBudget method.

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

• src/index.ts:116-118 (schema)

  Zod schema defining the input validation for the budget_id parameter used in the get_budget tool.

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

• src/index.ts:160-170 (registration)

  The tool definition object registered in the tools array, providing the name, description, and input schema for list_tools.

  {
    name: "get_budget",
    description: "Get detailed information about a specific budget including accounts, categories, and settings.",
    inputSchema: {
      type: "object" as const,
      properties: {
        budget_id: { type: "string", description: "The budget ID (use 'last-used' for most recent)" },
      },
      required: ["budget_id"],
    },
  },