> ## 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.

# buy_set_default_address

> Set the default delivery address at a linked merchant

Sets the default delivery address on a linked merchant account, using an id from `buy_addresses`. New orders default to it.

<Note>Not advertised in `tools/list` by default — the [buy](/companies/mcp/tools/buy) tool covers this conversationally. Expert integrations can still call it by name.</Note>

## Parameters

| Parameter    | Type   | Required | Description                            |
| ------------ | ------ | -------- | -------------------------------------- |
| `merchant`   | string | Yes      | Merchant slug (for example `doordash`) |
| `address_id` | string | Yes      | The address id from `buy_addresses`    |

## Returns

A confirmation that the default delivery address is set, including the address id. Failures return a short error message.

## Example

```json theme={null}
{ "name": "buy_set_default_address", "arguments": { "merchant": "doordash", "address_id": "addr_77h2" } }
```