ProofCheck MCP Server

by something-agent Your server? Claim it

answering

ProofCheck is answering right now. Last checked 6 min ago. It exposes 5 tools. Last commit 28 Oct 2026.

Free x402 offer/receipt checker: verifies signatures and whether the signer fits the host.

Uptime history 5 days of history · worst day 99%

5 days agonow

100.0%

Uptime 24h

92 of 92 checks

Tools

read from the server

99 ms

Response time

average over 24h

Stars

last commit 28 Oct 2026

What changed 1

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 28 October 2026. No other catalogue keeps this.

28 Oct a tool changed version

ProofCheck missed one check this week

Everything else answered, so this is steady rather than shaky. We check every 15 minutes, which is how a one-off gets told apart from the start of a pattern, and how you hear about the next one within the hour instead of from your users.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 6 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add proofcheck --transport http https://proofcheck.something-agent.workers.dev/mcp

Settings → Connectors → Add custom connector, then paste this address

https://proofcheck.something-agent.workers.dev/mcp

~/.codex/config.toml

[mcp_servers.proofcheck]
url = "https://proofcheck.something-agent.workers.dev/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "proofcheck": {
      "url": "https://proofcheck.something-agent.workers.dev/mcp"
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "proofcheck": {
      "type": "http",
      "url": "https://proofcheck.something-agent.workers.dev/mcp"
    }
  }
}

Available tools 5

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

verify

verify_offer

Verify an x402 signed offer (EIP-712 or JWS): signature, expiry, match to accepts[], and signer-authorization evidence (payTo, did:web, DNS _controllers, ERC-8004). Free.

verify_payment_required

Verify every signed offer inside a PaymentRequired object (pass the decoded JSON, or the raw base64 PAYMENT-REQUIRED header). Free.

verify_receipt

Verify an x402 signed receipt (EIP-712 or JWS) returned in the settlement response: signature, freshness, payer/resource/transaction match, signer-authorization evidence. Free.

lookup

lookup_erc8004_agent

Read-only ERC-8004 identity lookup (owner, agentWallet, registration file, endpoint-domain verification) on Ethereum, Base, Optimism, Arbitrum, Polygon, BNB, Avalanche, Gnosis, Celo, Linea or Scroll.

preflight

preflight_x402_endpoint

Unpaid preflight of an x402 URL: fetch its 402, summarise accepts[]/extensions, verify any signed offers and report who can vouch for the signer. Never pays. Free.

Endpoints

URL	Transport	State	Latency	Checked
https://proofcheck.something-agent.workers.dev/mcp	streamable-http	answering	98 ms	6 min ago

Alternatives to ProofCheck

same job, measured the same way

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MCP server for verifying receipts: POPCORN-WITNESS/2.0 signature, digest, and time. Free, read only.

1 tools answering

Wayreceipt

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Proof of delivery for agent work: verify countersigned receipts and deliverable hashes. Free.

4 tools answering

ScreenVerity

by williamblakecunningham-max

Free U.S. exclusion, debarment and licence screening with a signed receipt of the lists checked.

38 installs/wk local only

Baton

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Hand off AI work with a signed Verification Receipt — an independent verifier proves it runs.

43 installs/wk 45 tools answering

Blackwall X402 Guardrail

by blackwalltier

Keyless hosted MCP: pre-signature x402 payment verdict (GO/HOLD/STOP) with a signed receipt.

1 tools answering

AstraNL local proof NL

by astranl

Verify a place in the Netherlands: a verified local hand checks it, you get a sealed receipt.

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Pactlyst.ai — PactCheck document review for agents

by fikpeze123

Score documents and check agent work — signed PactCheck Receipts: proof-of-review for agents.

answering

Agent Receipt Verify

by holistis

Checks x402 endpoint conformance before an agent pays, and links the receipt to its settlement.

local only

ProofCheck — questions

Answers built from our own checks of this server.

What can ProofCheck do?

It exposes 5 tools, read directly from the server on our last check. Among them: lookup_erc8004_agent, preflight_x402_endpoint, verify_offer, verify_payment_required, verify_receipt. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is ProofCheck working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 99 ms. The bar chart above shows every period we have measured.

How do I connect ProofCheck?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does ProofCheck need an API key?

No. ProofCheck completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 5 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is ProofCheck?

It answers our handshake in 99 ms on average, which is faster than 92% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.

Is ProofCheck open source?

The code is open source: it is published under the MIT licence, written in TypeScript and 0 stars on GitHub. The licence covers the code in the repository, not the hosted service at proofcheck.something-agent.workers.dev, which runs on its operator's own terms.