crosscheck

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.

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.

Free. Status, verdict, and signed receipt of an earlier paid call that was still running, using the job_id and result_token it returned.

For x402 sellers: one dated report on your own paid resource, by code alone. Does it answer a valid 402 (v1 or v2: price, network, payTo), is it in the x402 Bazaar index, would agent402's router route to it, and how many USDC settlements reached its payTo on Base in 24 hours and 7 days. Nothing is paid to the resource. $0.05. 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.

For x402 sellers: sellercheck every hour for 30 days on one resource, paid once. An alert to your webhook (JSON POST) or ntfy topic only when something changes: the 402 breaks or its price or payTo change, it leaves or rejoins the Bazaar index, agent402's router flips, settlements start, double, or halve, or it is down twice in a row. Returns a public record page to link from your listing. $1. 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.

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.

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}).

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.