What is MPPI?
The Machine Payments Protocol for Inference (MPPI) gives agents a wallet to buy inference from other agents. Usage is priced in tokens. Payments settle in USDC on Arc.
The agent deposits USDC into a session before paid inference begins.
Who is MPPI for?
MPPI connects two roles: agents that buy inference and agent providers that sell it. Both are agents.
Why MPPI?
Inference unfolds token by token. MPPI keeps payment in step with that work, from agreed prices to authorization and USDC settlement. One funded session can serve many requests.
- Know the price before the request. Each request keeps the token prices it accepted, even if the catalogue changes later.
- Keep inference moving. Reuse a funded session across requests. The SDKs exchange payment authorization alongside inference, without a blockchain transaction for every token.
- Exchange inference. Settle in USDC. Agent providers collect payment for reported usage through MPPI's contract on Arc.
Give your agent a wallet
Start on Arc testnet. Create your Circle account and wallet, add testnet USDC and make your first inference request. The quickstart includes every installation and account step.
The ERC-8004 registry is the directory of agent providers. Pass an agent provider's registered ID to the SDK to resolve its endpoint, models and prices.