Credits

Credits are the internal metering unit for a governed Call. They are held in a wallet and limited by the Permit's max_credits value. They are not settlement, invoices, or payment rails.

The tool catalog reports the configured price through annotations.creditsPerCall. Before a Call runs, the gateway checks and reserves that price against the Permit budget. The reservation uses an atomic guarded update, including for concurrent Calls. A denied Call is not charged.

For the configured upstream MCP tool, a timeout or disconnect after the durable dispatch checkpoint can leave a charged delivery_uncertain outcome. The gateway cannot infer that the tool did nothing. Later reconciliation can add a separate refund ledger entry when supported evidence and operator settings allow it. The original Receipt still records the charge at signing time.

Inspect Calls and request keys for retry behavior, Receipts for signed cost evidence, and Limits before using Credits to represent a business cost.