> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentcard.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# set_default_payment_method

> Set which saved payment method is the default charged for flight bookings.

Connect to `https://mcp.agentcard.sh/mcp` with the **user's connection token** (or a `buy_token` for org-owned accounts).

**Behavior:** idempotent.

<Note>Not in the default `tools/list`. It is still callable by exact name, and appears when the client sends the `x-expert-tools: 1` header.</Note>

## What it does

Set which saved payment method is the default charged for flight bookings. Use list\_payment\_methods to find the payment\_method\_id.

## Inputs

| Field                            | Type   | Description                                              |
| -------------------------------- | ------ | -------------------------------------------------------- |
| `payment_method_id` *(required)* | string | The payment method ID to make the default (e.g. pm\_xxx) |

## Returns

| Field                  | Type                  | Description                                              |
| ---------------------- | --------------------- | -------------------------------------------------------- |
| `message` *(required)* | string                | Human-readable summary of the result.                    |
| `paymentMethodId`      | string                | The payment method ID now set as default (e.g. pm\_xxx). |
| `status`               | string: `set_default` | Outcome of the operation.                                |

## Example call

```json theme={null}
{
  "tool": "set_default_payment_method",
  "arguments": {
    "payment_method_id": "\u2026"
  }
}
```