ASPERN: counterparty checks for agents

Connect it to your AI

Claude Code

claude mcp add --transport http aspern https://aspern.org/mcp

Claude, ChatGPT, Cursor and other apps

Add it as a custom connector with this URL (Streamable HTTP):

https://aspern.org/mcp

Cursor, VS Code and other apps (mcp.json)

{
  "mcpServers": {
    "aspern": {
      "url": "https://aspern.org/mcp"
    }
  }
}

Tools it offers

39 tools, as the server itself reported during our check on Oct 31, 2026.

• identifyCall this FIRST whenever you hold something other than a wallet address. Give it a transaction hash, an http(s) URL, a hostname or an ERC-8004 registration number and it says which party that is, with the evidence for th
• check_service_endpointCall this before connecting to a service. Give it the http(s) URL of an MCP or A2A endpoint and it says who declares it, whether our daily probe reached it, what it answered with, and how many of the last readings answer
• preflight_paymentCall this immediately before sending a payment, every time — not once per counterparty. It weighs THIS payment (the amount, the chain, the endpoint) against what the address has actually done: the price the seller themse
• vault_assessmentTHE HASH-COMMITTED ASSESSMENT OF A VAULT, in the shape ERC-8004’s Reputation Registry points at, and the only thing here a third party can publish on chain under their own name. Until 2026-10-21 this document was reachab
• vault_exitsSEND `exitAmountUsd` WITH THE POSITION YOU ARE WEIGHING and this answers whether that size has ever cleared here: the schema has carried it since 2026-10-08, and an auditor still had to find it by guessing because this s
• vault_risk_dimensionsSIX RISKS, NOT ONE WORD, across every vault we score. A risk band is a weighted whole and a reader takes it as a summary of everything, which it is not: ours weighs drawdown, crowding, exit, concentration and consistency
• portfolio_screenREAD THE VAULTS YOU HOLD TOGETHER. This one is about a SET rather than a single subject; an allocator does not hold one subject. This answers the three questions that only exist across holdings and that no vault page can
• capital_coverageBEFORE YOU TRUST ANY COVERAGE FIGURE FROM US, ask this. It says how much of the market each vault reading actually covers, counted TWO WAYS: by number of open vaults and by the capital in them. They differ by a lot, and
• exit_lifecycle_coverageHOW MUCH OF THE WAY OUT WE CAN SEE, phase by phase, across every open vault. Getting out has four phases — a request filed, something set aside to claim, money that actually left, and an attempt that failed — and we read
• endpoint_coverageBEFORE YOU TREAT ANY ENDPOINT AS RELIABLE, ask how well we know. There is no uptime number here and there will not be one, because the states mean different things and summing them produces a figure about nothing: a 402
• payment_evidenceBEFORE YOU QUOTE ANY FIGURE FOR AGENT COMMERCE, ask which of three it is. Every payment shown to be one, x402 and ACP, is split into three figures that NEST and are never added up (x402 counts only the `protocol`, `route
• evidence_forEverything we hold about one subject, as edges, each carrying where it came from. Use it when you need to explain a decision rather than just make one, or to see what is MISSING before you act. Every edge has `source`, `
• evaluate_actionCall this when you are about to DO something and need one answer you can act on: pay an address, connect to an MCP server, call a tool, or put capital into a vault. The answer depends on the AMOUNT, the ACTION, the POLIC
• evaluate_vault_decisionCall this before an agent moves capital into or out of a vault, with the decision it is about to make: the vault, the amount, the MANDATE it must stay inside and the CLAIMS the decision rests on. It is judged against our
• test_purchaseWALK THE WHOLE PURCHASE OF AN x402 ENDPOINT WITHOUT PAYING, in the order a buyer actually asks the questions, stopping at the first one that objects. All five are asked in one pass and in that order, so the walk stops wh
• knock_on_endpointKNOCK ON AN x402 ENDPOINT AND GET WHAT IT SERVED. `test_purchase` beside this walks a buy WITHOUT paying and stops at the quote; its own caveat has always said that only paying and reading the answer establishes what arr
• endpoint_disagreementsWHICH ENDPOINTS CONTRADICT THEIR OWN LISTING: they ask to be paid at an address the catalogue entry they published does not name. The contradiction appears only when the live handshake and the published listing are held
• list_x402_endpointsWHICH ENDPOINTS A PAYEE SELLS, or which ones match some text. The sharpest check a payment can get is the endpoint being bought, and until this a caller had to know its URL by heart. Nearly every catalogued resource name
• list_policiesThe policies evaluate_action can be run under, in full: every rule, its id and the sentence it checks. Published deliberately, including to the agents being evaluated — a rule nobody can read is a rule nobody can correct
• counterparty_checkBefore paying or hiring an agent: what the chain records about that address. Independent payers (counterparties that paid it and were never paid back), the ones it does pay back, how concentrated its custom is, WHETHER T
• vault_checkBefore putting capital into a vault: what the record shows about it. The headline is what a holder ACTUALLY EARNED set against the advertised rate, with the risk band, the components that apply, who runs it, and `keys`:
• find_vaultsFind a vault by what it has DONE rather than what it is called. Free. The filter worth knowing is `earned`: `short` returns the vaults where a holder earned LESS than the venue advertises — how many there are is in the a
• operator_checkThe question that follows vault_check: who runs the money, and how much of it is their own. Free. Read `ownShare` with its limits, which travel inside it: the leader’s holding is readable on Hyperliquid and Drift ONLY, s
• list_vaultsThe vaults we read, so a caller holding a name rather than a slug can find the one it means. Free. Absence from this list means we do not read that vault, never that it does not exist.
• find_agentsFind agents to hire by what the chain records rather than what they claim: filter every address ever paid on x402, Virtuals ACP, the Olas mech marketplace or Masumi by independent payers, dealings, ACP completion, whethe
• counterparty_historyHow one agent’s record has moved: dealings, independent payers, concentration and delivery, day by day. PAID, one cent a call over x402 — the median price of this rail. Without payment the tool answers with the price and
• vaults_earnedWhat depositors actually KEPT, against what their vault advertised. READ `population` BEFORE QUOTING ANY SHARE FROM THIS. The comparison covers only the vaults where we hold BOTH an advertised rate and a realised one, wh
• agent_changesWhat moved in the agent record, across every agent, since a date. The counterparty check answers what is true about one address NOW; this answers what changed, for all of them, which is the question anybody holding a lis
• counterparty_bulkCheck up to fifty addresses in one call, each with its observations, AND what the set shares underneath: the parties that two or more of them pay. That second part is the one answer no per-address row can contain, becaus
• agent_dependenciesIf your firm relies on several external agents, what do they rest on AT ONCE? Give it two to twenty-five addresses and it finds the parties more than one of them pays. THE PRODUCT IS THE DISTINCTION, NOT THE JOIN: findin
• agent_businessDoes this agent have a BUSINESS, and can any of it be demonstrated? Six questions an investor, a marketplace or an operator actually asks, each answered separately: are the addresses paying it really independent customer
• agent_economic_profileOne agent, four readings, in the order a buyer actually asks them: what it EARNS and from whom, whether its contracted work FINISHED and who signed it off, who it RESTS ON as a supplier, and whether it is still TRADING a
• exit_screenYOU HAVE A SIZE AND YOU WANT TO KNOW WHERE IT HAS ACTUALLY CLEARED. Every other exit reading here is about one vault; this asks the same question across every vault whose withdrawal history we have read, which is the que
• vault_exit_confidenceBefore you put capital in, ask what evidence there is that you could get a PARTICULAR amount back out. Every other reading about a vault is about return or about risk of loss; this is about the practical question a holde
• check_actionCALL THIS BEFORE YOUR AGENT SIGNS ANYTHING THAT MOVES MONEY. One request instead of five: it reads the counterparty record, decodes the calldata you are about to sign, looks up the seller’s own catalogue listing, runs an
• inspect_paymentCall this with the CALLDATA you are about to sign, before you sign it. Every other check here asks whether an address is worth dealing with; this asks whether the transaction is the one you think it is, and the two catch
• record_receiptCall this AFTER you have paid an address or called a tool, to put what you did on the record. Until now this platform answered "should I" and never heard what happened, which is the difference between a lookup and a cont
• receipt_statusWhat became of a receipt you recorded with `record_receipt`. We do not take a receipt on your word: each one is read against the payments WE read from the chain and judged `verified` (it paid the subject and the amount a
• monitor_subjectAsk to be told when the answer about an address CHANGES. The dimensions are the ones the counterparty check already answers, so this is that same reading on a schedule rather than a second opinion; what it adds is the co

Questions