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crosscheck

by crosscheckapi.com · remote · local (npm) · no sign-in to list tools · v0.5.5 · published by com.crosscheckapi

Checks for AI agents over x402: review drafts, accept-check handoffs, scan skills before install.

Changes · 5
CompareRegistry entry

6 tools: 5 change things and 1 only read.

Scanned Oct 21, 2026

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

claude mcp add --transport http crosscheck https://crosscheckapi.com/mcp

Tools

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

6 tools

Changes things 5Claude Code: ask
  • acceptChecks work another agent handed back against the task it was given, before you pay, release escrow, or pass it on.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Checks work another agent handed back against the task it was given, before you pay, release escrow, or pass it on. Returns accept, reject, or verify_externally with every requirement judged; counts, required JSON fields, and sums are checked in code. Optional payment_tx is verified on chain. $0.03 base. Paid per call in USDC over x402 (Base, or free test USDC on Base Sepolia). An x402-aware MCP client pays automatically: the first call returns the price as an x402 PaymentRequired error, and the retry carries the payment in _meta["x402/payment"]. Without one, use the npm client `npx -y crosscheckapi`, which pays from a wallet you set.
  • checkIndependent review of a draft (email, report, summary, PR description) before its human sees it.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Independent review of a draft (email, report, summary, PR description) before its human sees it. Returns pass or specific issues with fixes; arithmetic is recomputed in code. With request (what the human asked), it also checks the draft answers that. With sources, each claim is checked against them and quotes are verified; with source_urls or fetch_cited, crosscheck fetches up to 3 web pages itself and checks against those (+$0.01 a page, and a dead link the draft gives fails it). $0.02. Paid per call in USDC over x402 (Base, or free test USDC on Base Sepolia). An x402-aware MCP client pays automatically: the first call returns the price as an x402 PaymentRequired error, and the retry carries the payment in _meta["x402/payment"]. Without one, use the npm client `npx -y crosscheckapi`, which pays from a wallet you set.
  • resultFree.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Free. Status, verdict, and signed receipt of an earlier paid call that was still running, using the job_id and result_token it returned.
  • skillcheckSecurity review of a skill or MCP server's files before you install or connect it: read, never run.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Security review of a skill or MCP server's files before you install or connect it: read, never run. Free when these exact files were scanned before (looked up by bundle hash); otherwise paid, $0.03 base. Never says safe. Paid per call in USDC over x402 (Base, or free test USDC on Base Sepolia). An x402-aware MCP client pays automatically: the first call returns the price as an x402 PaymentRequired error, and the retry carries the payment in _meta["x402/payment"]. Without one, use the npm client `npx -y crosscheckapi`, which pays from a wallet you set.
  • verify_receiptFree.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Free. Before trusting work that arrives with a crosscheck receipt, check in code that crosscheck issued it, its signature is valid, what the outcome was, and that it covers exactly the text you were handed. Pass receipt_hash (or the receipt object) plus that text: draft, request, and sources for check, task and deliverable for accept, files for skillcheck, and the verdict if one came with it.
Only reads 1Claude Code: allow
  • skillcheck_lookupFree.No findings

    Why it is in this group

    • The name "skillcheck_lookup" says "lookup": a word for reading.
    Description, as the server wrote it
    Free. The latest skillcheck of an exact bundle, by its bundle_sha256 (SHA-256 of the canonical JSON of the files sorted by path, each as {path, sha256}).

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.

Install

Pinned to version 0.5.5. Values in angle brackets are yours to fill in.

claude mcp add --transport http crosscheck https://crosscheckapi.com/mcp

Run in a terminal.

Claude Code permissions

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

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__crosscheck__skillcheck_lookup"
    ],
    "ask": [
      "mcp__crosscheck__check",
      "mcp__crosscheck__accept",
      "mcp__crosscheck__skillcheck",
      "mcp__crosscheck__verify_receipt",
      "mcp__crosscheck__result"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as crosscheck. Review it before you use it.