:::endpoint POST /v1/me/mail/messages/{id}/answered

Sending a reply sets this by itself. This is for the two cases where that does
not happen: the exchange settled by telephone never gets its mark from the
sending that never happened, and the answer that went to the wrong person is one
somebody has to be able to take back.

The mark clears again by itself when a new message arrives in the conversation.

## Request

```bash
curl -X POST https://api.proppertrading.com/v1/me/mail/messages/1552/answered \
  -H "Authorization: Bearer ptat_9f2c1a44_3b8e7d2f5c9a1b4e6d8f0a2c4e6b8d1f" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 1b2c3d4e-5f60-4718-9a2b-3c4d5e6f7081" \
  -d '{"answered": true}'
```

| Field      | Type    | Description |
| ---------- | ------- | ----------- |
| `answered` | boolean | Required    |

## Response

```json
{
    "data": {
        "object": "mail_answer",
        "message_id": 1552,
        "thread_id": 611,
        "answered": {
            "id": 1,
            "name": "Mick",
            "at": "2026-08-19T18:04:47.000000Z"
        }
    },
    "meta": { "request_id": "req_01kz4bkr1aj1gv63d8fv3133ey" }
}
```

`answered` is null once the mark is taken off.

## Errors

| Status | Code                      | Meaning                                   |
| ------ | ------------------------- | ----------------------------------------- |
| 400    | `missing_idempotency_key` | Every POST needs one                      |
| 403    | `insufficient_scope`      | This device does not hold `mail:write`    |
| 404    | `resource_not_found`      | No such message in a mailbox you can read |
| 422    | `validation_failed`       | `answered` missing or not a boolean       |