Function: get_credit_card_balance
This tool belongs to the travel system, which allows users to book flights, manage credit cards, and view budget information. Tool description: Get the balance of a credit card
Parameters: access_token: type: string
description: The access token obtained from the authenticate
card_id: type: string
description: The ID of the credit card
Required parameters: access_token, card_id
Response: card_balance: type: float
description: The balance of the credit card