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BuildAgents

Budgets for software that spends.

Every agent gets an isolated balance, a scoped API key and MCP endpoint, and a USDC vault its session key can draw from only within the limits you sign on-chain.

Balance
isolated from yours
API key
scoped to the agent
MCP endpoint
8 tools
USDC vault
limits set on-chain

How an agent pays its own way

You decide the ceiling once. The agent works inside it without asking again.

  1. Set its budget.

    A daily spend limit caps the agent's key per UTC day. A threshold, a top-up amount and a maximum number of top-ups a day decide when and how much it can refill.

    every limit can be changed later

  2. Hand it the key.

    The agent's API key is shown once, at creation. Use it with any SDK or MCP client; it reaches only the agent's own balance.

    lost keys are replaced, never recovered

  3. Fund its vault.

    One transaction creates the vault, registers the agent's session key with your limits and, if you like, deposits USDC.

    limits enforced on-chain

  4. It tops itself up.

    When the balance drops below the threshold, the session key moves USDC from the vault into credits, within the limits you signed.

    automatic, or on request through MCP

What the session key can do

It is the only key the agent's top-ups use, and the program limits it on every call.

It can

  • Move USDC from its own vault into the agent's credit balance.
  • Top up by no more than the per-top-up amount, and no more than the daily cap.

It cannot

  • Send USDC to any other address.
  • Outlast you: pause or revoke the agent, withdraw from the vault or close it at any time.

MCP tools every agent can call

  • get_balance
  • get_usage
  • list_models
  • estimate_cost
  • get_topup_policy
  • set_low_balance_threshold
  • request_topup
  • get_gateway_status

Connect it in one command

The MCP guide has the endpoint, the client configuration and what each tool does.