get_connections_status reports those platforms. list_connected_accounts groups the accounts. Platform tools then take the account id you name. Pass it as a string.
The agent must not pick an account you did not name when several are connected. Ask it to list them and wait.
What the billing page shows
Usage & Billing lists one active ad account per platform on Free, Plus, and Pro, and up to five active accounts per platform on Max. Those are the allowances printed on the plan cards. Tool-call quotas are separate and are enforced. See Pricing. Google manager accounts still appear throughget_google_ads_accounts. Amazon profiles appear through get_amazon_profiles. Choosing a client account under a manager, or a profile under a seller, is that id argument. It is not a second ADSMCP login.