# See the account’s usage

What the key’s account has used against its plan, and its most recent calls with their outcome or refusal code.

- REST: `GET https://montaye.com/v1/usage` with `Authorization: Bearer <key>`
- MCP tool: `usage_list` at https://montaye.com/mcp
- Answer: `{ "result": …, "usage": … }`; refusals are `application/problem+json`

## Refusals

- [`input_invalid`](https://montaye.com/refusals/input_invalid) (400): The request does not match the action’s input schema.
- [`key_missing`](https://montaye.com/refusals/key_missing) (401): This action needs an API key (Authorization: Bearer <key>).
- [`key_invalid`](https://montaye.com/refusals/key_invalid) (401): The API key is unknown, revoked or expired.
- [`rate_limited`](https://montaye.com/refusals/rate_limited) (429): Too many requests from this client; slow down.
- [`database_unavailable`](https://montaye.com/refusals/database_unavailable) (503): The ledger database cannot be reached right now.