YNAB MCP Server

Instructions

Implementation Reference

• src/tools/DeleteTransactionTool.ts:25-60 (handler)

  The main handler function that executes the deletion of a YNAB transaction using the API. Handles budget ID resolution, API call, success/error responses.

  export async function execute(input: DeleteTransactionInput, api: ynab.API) {
    try {
      const budgetId = getBudgetId(input.budgetId);
  
      const response = await api.transactions.deleteTransaction(
        budgetId,
        input.transactionId
      );
  
      if (!response.data.transaction) {
        throw new Error("Failed to delete transaction - no transaction data returned");
      }
  
      return {
        content: [{
          type: "text" as const,
          text: JSON.stringify({
            success: true,
            transactionId: response.data.transaction.id,
            message: "Transaction deleted successfully",
          }, null, 2),
        }],
      };
    } catch (error) {
      console.error("Error deleting transaction:", error);
      return {
        content: [{
          type: "text" as const,
          text: JSON.stringify({
            success: false,
            error: getErrorMessage(error),
          }, null, 2),
        }],
      };
    }
  }

• src/tools/DeleteTransactionTool.ts:5-10 (schema)

  Exports the tool name, description, and Zod input schema defining budgetId (optional) and transactionId parameters.

  export const name = "ynab_delete_transaction";
  export const description = "Deletes a transaction from the budget. This action cannot be undone.";
  export const inputSchema = {
    budgetId: z.string().optional().describe("The ID of the budget (optional, defaults to YNAB_BUDGET_ID environment variable)"),
    transactionId: z.string().describe("The ID of the transaction to delete"),
  };

• src/index.ts:93-97 (registration)

  Registers the tool with the MCP server using name, custom title, description, inputSchema from the tool module, and async executor calling the tool's execute function with API.

  server.registerTool(DeleteTransactionTool.name, {
    title: "Delete Transaction",
    description: DeleteTransactionTool.description,
    inputSchema: DeleteTransactionTool.inputSchema,
  }, async (input) => DeleteTransactionTool.execute(input, api));