eip155:8453) and paid with x402. You pay only for calls that succeed: a 400, 422, or 500 never settles.
x402 prices
USDC has 6 decimals, so
100000 base units is 0.10 USDC. The amount in the 402 offer is always in base units and already holds the total for the request.
Worked examples
A monitor session is paid up front for the whole window. Closing the socket early does not refund the unused hours, so buy the window you need and renew it when the server sends
session_expired.
What is free
- MCP
initialize,tools/list, and the tool schemas. Onlytools/callis paid. - The
402offer itself. Asking for the price costs nothing. - Every route for partners who send
X-Partner-NameandX-Partner-API-Key.
Partner plans
Products that call the API at volume, or hold many monitor sockets, can take a partner key on a monthly plan instead of paying per call. Write to business@ampli.net.The live price is the one in the
402 offer you receive. If a price changes between the offer and your retry, the server answers with a new 402 carrying the current price, and nothing is charged.