Summary
Public username check. Query name. Returns name, normalized, available, optional reason (invalid_username, reserved_username, or taken), and suggestions (up to 5 names that are valid, not reserved, and not already an inbox). No API key. 30 requests per minute per IP, then HTTP 429 rate_limited with Retry-After, retry_after_seconds, and resets_at. Responses include RateLimit-Limit, RateLimit-Remaining, and RateLimit-Reset (seconds until the window ends; on HTTP 429 it matches Retry-After). A lookup that cannot be completed returns HTTP 503 username_check_unavailable with those retry fields. If the limit cannot be checked, the response is HTTP 503 rate_limit_unavailable with those retry fields. The body does not say who holds a name. MCP: check_username true on cooper_onboard or cooper_create_inbox.
Request
This call has no JSON body.
Response
HTTP 200. Sample values illustrate the schema.
{
"name": "string",
"normalized": "string",
"available": true,
"suggestions": [
"string"
]
}Errors
- HTTP 429 rate_limited
- HTTP 503 username_check_unavailable
- HTTP 503 rate_limit_unavailable
Idempotency
This route does not document Idempotency-Key or client_id.