Known prepaid-credits tier keys the backend exposes today. 10_USDC is
the canonical agent top-up: 10 USDC → 1,000,000 additional credits,
matching the agent plan's signup pricing and overageCost. The backend
also exposes 4_USDC and 5_USDC tiers but only 10_USDC is
advertised by the CLI/MCP. The string & {} opening keeps the type
future-proof for tiers added later without an SDK patch.
Known prepaid-credits tier keys the backend exposes today.
10_USDCis the canonical agent top-up: 10 USDC → 1,000,000 additional credits, matching the agent plan's signup pricing andoverageCost. The backend also exposes4_USDCand5_USDCtiers but only10_USDCis advertised by the CLI/MCP. Thestring & {}opening keeps the type future-proof for tiers added later without an SDK patch.