Foundry: prepaid AI compute in USDF

Measured conclusion: Deep-tested. L2 outcome: tools_ok.

Prepaid AI compute in USDF: models, quotes and chat with a receipt; pay per call (x402) or by key

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Copy this into your MCP client config:

{
  "mcpServers": {
    "Foundry: prepaid AI compute in USDF": {
      "url": "https://api.usdf.fi/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (10)

• list_models read-only

  Models the gateway serves with their prices (USD per 1M tokens, the same figure in USDF), context window, output limits and whether a route is available right now. No key needed.

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

• quote read-only

  The hold the chat tool places before running a request, in USDF and USD (output capped at 4096 tokens). It is an estimate, not a ceiling: a completed request is billed the provider's reported usage, normally less. Pass prompt or messages. No key needed; a request for attested hardware (a :private model id or provider.private), and any request from a Private-tier key, is quoted on its attested routes, at the model's price.

  Parameters:

  • model (required) — string — Model id from list_models
  • prompt — string — Prompt text, sent as one user message
  • messages — array — Chat messages in the OpenAI format: objects with a role (system, user, assistant or tool) and content (text, or an array of content parts)
  • provider — object — Routing asks as on the REST API, for example {"private": true} for attested hardware this gateway verified, at the model's price
  • max_tokens — number — Output token budget, a positive integer; defaults to the model's default_max_output, capped at max_output

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

• list_tools read-only

  Tools you can call through POST /v1/tools/{id}, paid from the same balance and key as chat, each with its price in USDF (what it costs plus 5% at most) and the input it takes, ordered by title. Every tool listed can be called now. q keeps the tools whose id, title or description has those words; a page holds up to 200, and page.next names the next one. No key needed.

  Parameters:

  • q — string — Words a tool's id, title or description has
  • cursor — string — page.next of the page before

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

• quote_tool read-only

  What a call to a tool would hold for this input before it runs (its most it can cost), in USDF and USD, with the tool's price. It checks the input as the call would, and runs and holds nothing. No key needed.

  Parameters:

  • tool (required) — string — Tool id from list_tools
  • input — object — The input the call would send, as in the tool's input schema

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

• x402_pay

  Calls a URL that asks for an x402 payment and pays it for you: the gateway pays the seller in USDC from its own float and charges this key in USDF cost plus 5% at most, no minimum (the seller's amount and a fee of at most 5% of it; never free credit), within the key's and its agent's limits. Needs an API key. Returns the seller's answer with the payment and its receipt; a payment is charged only once the chain shows it, and one that never settles costs nothing. quote: true answers what it would cost and pays nothing. Third-party tools to call this way are listed under marketplace in list_tools (GET /v1/tools?source=marketplace).

  Parameters:

  • url (required) — string — The seller's URL (https)
  • body — The request body: text, or JSON sent as application/json
  • quote — boolean — Answer the price and pay nothing
  • method — string — Default GET, or POST when a body is given
  • headers — object — Headers for the seller (the payment headers are the gateway's)
  • network — string — Pay on this network only: its CAIP-2 id, one GET /v1/x402/payer lists
  • max_price — string — The most to pay in USDF, the fee included ("0.05")

  Hints: read-only no · destructive no · idempotent no · open-world yes

• agents_market_search read-only

  Agents, APIs and tools priced per call, in one market, every listing in the same shape: its id (svc_...), name, description, tags, site and logo, how it is called (GET or POST), what one call costs in USDF from this key's balance, input and output examples, and the data policy. Ordered by popularity (default), price or newest. No key needed to search; agents_market_call calls one.

  Parameters:

  • q — string — Words to find in the name, description, tags or host
  • tag — string — Only listings with this tag
  • sort — string — popular (default), price (cheapest first) or new
  • limit — integer
  • offset — integer
  • max_price — string — The most a call may cost in USDF ("0.01")

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world yes

• agents_market_call

  Calls a listing of the agents market by its id (svc_..., from agents_market_search), paid from this key's USDF balance (never free credit) within the key's and its agent's limits and at most max_price: what one call costs and nothing on top; a call its seller does not answer 2xx costs nothing, or no more than what its seller kept of it. Every listing is called the same way, and answers 503 market_calls_unarmed while calls to the market are not switched on. Needs an API key. Returns the seller's answer and the receipt. The input goes to the seller, whose own policy governs what it keeps.

  Parameters:

  • id (required) — string — The listing's id (svc_...), from agents_market_search
  • max_price (required) — string — The most this call may cost in USDF ("0.05"): required, as a seller may change its price; the listing's price is in agents_market_search
  • input — What the call sends: JSON for a POST listing, an object of plain values (its query) for a GET one

  Hints: read-only no · destructive no · idempotent no · open-world yes

• chat

  Runs a chat completion and returns the text with its receipt (tokens, price, cost, balance, settlement). With an API key it spends from that key's balance, holding the most the request can cost first. Not streamed. Output is capped at 4096 tokens. A call without a progress token answers within 55 s of arriving. With a progress token, progress is sent every 15 s and the call may run 10 minutes, so the client must reset its timeout on progress (resetTimeoutOnProgress: true in the TypeScript SDK) or wait that long. At its deadline, or when the client's connection closes, a call is cut: the text produced so far is returned with finish_reason "length" and billed on the provider's usage report where the provider gives one, otherwise on an estimate never above max_tokens; for a model whose reasoning is not streamed, at the held output budget. Cancellation messages are not supported: a call the client stops waiting for without disconnecting runs to completion or its deadline and is billed. With no key, the call is paid with x402 in USDF (signature transfer) or USDG (signed transfer), as POST /x402/v1/chat/completions: without a payment it returns isError with the payment requirements (x402Version, resource, accepts) as structuredContent; sign one accept and call again with the payment in _meta["x402/payment"], the payment argument or the PAYMENT-SIGNATURE header. The quote is the call's maximum cost at the published price (prompt at one token per byte, output at max_tokens, capped as above, no minimum), paid up front; the call is charged what it uses at that price and the rest is refunded in the asset paid, the gateway paying the gas. A paid call runs to its end or its deadline whether or not the client waits and returns the receipt and _meta["x402/payment-response"]; at the deadline the text so far is returned with finish_reason "length" and a note, charged what it used and the rest refunded. A call no provider accepted before its deadline, or whose provider failed or ended with nothing, is refunded in full in the asset paid; so is one cut by the deadline after the provider accepted it, with nothing produced. A call with less than 20 s left before its deadline is refused before the payment is settled (deadline_too_close), nothing charged. MPP clients pay the same quote: the payment-required result also carries _meta["org.paymentauth/payment-required"] with evm charge challenges (USDG by signed transfer authorization, USDF by signature transfer); call again with the credential in _meta["org.paymentauth/credential"], and the paid result carries _meta["org.paymentauth/receipt"].

  Parameters:

  • model (required) — string — Model id from list_models
  • messages (required) — array — Chat messages in the OpenAI format: objects with a role (system, user, assistant or tool) and content (text, or an array of content parts)
  • payment — With no key: the x402 payment for this call's quote, as the PAYMENT-SIGNATURE value (base64 JSON) or the payload object; _meta["x402/payment"] and the PAYMENT-SIGNATURE header are read too
  • max_tokens — number — Output token budget, a positive integer; defaults to the model's default_max_output, capped at max_output
  • temperature — number — Sampling temperature, 0 to 2

  Hints: read-only no · destructive no · idempotent no · open-world yes

• balance read-only

  With an API key: what the key can spend now, the account's balance and the amount held for requests running, and what is left of the key's budget, in USDF. With address instead, and no key: that wallet's USDF and USDG on the chain now, and how much USDF it lets the signature-transfer contract spend, which x402 payments come from.

  Parameters:

  • address — string — A wallet address (0x...): its USDF and USDG on the chain, with no key

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

• receipt read-only

  With the API key that made the request: its receipt, with the usage, the price sheet version, the cost and, once settled, the settlement, its transaction and the rows behind the onchain digest. With no key: the public receipt of any request id, x402 ones included, with its line in the usage log, the payment, the settlement and where its proof is (GET /x402/v1/receipts/{id}).

  Parameters:

  • request_id (required) — string — The id returned with the completion (also the x-request-id header)

  Hints: read-only yes · destructive not declared · idempotent not declared · open-world no

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Measured by MCPYP probing. Untested fields are omitted, never estimated. Listing is always free; MCPYP never proxies calls or stores user tokens.