| API key | caller credential for gateway, capability, and MCP execution |
| scope | permission such as invoke_provider, read_usage, or manage_keys |
| billing account | owner of API keys, membership, admission, and product usage |
| request credit | dashboard presentation of the currently allocated request_count allowance |
| admission | current account state and meter-specific raw-unit allocations used to authorize execution |
| usage fact | immutable raw-unit observation about a gateway or capability execution attempt |
| idempotency key | stable key that prevents double debit for the same accepted request |