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SignCheck

by youraitools.co · remote · local (npm) · no sign-in to list tools · v0.2.0 · published by co.youraitools

Pre-sign safety check for agent wallets: tx, EIP-712, EIP-7702, x402. By Crypto Money Maker

Changes · 1
CompareRegistry entry

1 tool: 1 change things.

Scanned Oct 22, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http signcheck https://api.youraitools.co/signcheck/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warncheck_signature

    The server marks "check_signature" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

1 tool

Changes things 1Claude Code: ask
  • check_signatureCall BEFORE your agent signs or sends anything from a wallet.Reads text others write1 finding

    Why it is in this group

    • The description's first verb is "call": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.

    Findings

    • Warn

      The server marks "check_signature" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Call BEFORE your agent signs or sends anything from a wallet. Decodes a transaction, an EIP-712 typed-data request (Permit, Permit2, EIP-3009 USDC authorizations, Seaport orders), an EIP-7702 delegation or an x402 payment (402 terms + payload) into plain English and returns SAFE / CAUTION / DANGER with risk flags (unlimited approvals, setApprovalForAll, fake USDC domains, x402 overpay or wrong payTo, OFAC SDN counterparties). Free preview tier (offline). The paid x402 endpoint /v1/check adds reasons, on-chain facts (spender is a wallet or contract, token metadata) and an eth_call simulation.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: true
    • idempotentHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or outbound.

Reads private data0
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write1
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out0
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Install

Pinned to version 0.2.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http signcheck https://api.youraitools.co/signcheck/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [],
    "ask": [
      "mcp__signcheck__check_signature"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as signcheck. Review it before you use it.

Capability tags behind 1 rule
  • mcp__signcheck__check_signature untrusted-input