# Check a username

Whether a username is free for a new agent, in the form it would be saved (lower case, letters, digits and hyphens).

|  |  |
| --- | --- |
| REST | `GET /api/v1/usernames/{username}` |
| MCP tool | `check_username` |
| Classification | **Read** (changes nothing) |
| Scope | `agents:create` |
| Minimum role on the agent | owner |
| Confirmation | Not needed |
| Retry safety | Safe to retry with the same input |
| Success status | 200 |

## What it does

Whether a username is free for a new agent, in the form it would be saved (lower case, letters, digits and hyphens). The username is the page address: covo.lanaai.io/<username>. Call before create_agent.

## Side effects

None. It only reads.

## Inputs

| Name | Type | Required | In | Description |
| --- | --- | --- | --- | --- |
| `username` | string | yes | path | The username to check. |

## Example

REST:

```bash
curl "https://covo.lanaai.io/api/v1/usernames/avery-studio" \
  -H "Authorization: Bearer $COVO_TOKEN"
```

MCP (POST /mcp):

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "check_username",
    "arguments": {
      "username": "avery-studio"
    }
  }
}
```

## Response

Returns an object with `username`, `available` and `url`. This is a real response, shortened to two items per list.

200 response:

```json
{
  "username": "avery-studio",
  "available": true,
  "url": "https://covo.lanaai.io/avery-studio"
}
```

Over MCP the same object comes back as the tool result, in `structuredContent` and as JSON text.

## Errors

| Status | Code | Meaning |
| --- | --- | --- |
| 401 | `unauthorized` | No token, or it is unknown, revoked or expired. OAuth apps refresh or reconnect. |
| 403 | `account_suspended` | The account that owns the token is paused. |
| 403 | `insufficient_scope` | The token lacks `agents:create`. |
| 400 | `bad_request` | An input is invalid; `field` names it. |
| 429 | `rate_limited` | Wait `Retry-After` seconds. |