Chain Evidence Check File
by Chain Evidence Check in Onchain & crypto
Chain Evidence Check — Judges whether an on-chain observation really proves a claim about a payment, a wallet or an RPC endpoint on an EVM chain, and answers as JSON with a binary verdict, the reason and the one check that would decide. Knows the readings that answer for the wrong thing - a null transaction receipt seconds after settlement, a block explorer that indexes a minute late and a balance view that lags its own transfer list, a public RPC endpoint that refuses receipts with an error or…
https://api.aiskills402.com/v1/skills/chain-evidence-check/file- Price
- $0.05
- per call in USDC
- Uptime
- 100%
- last 30 days
- Response time
- 563 ms
- 1.1 s slowest 5%
- Last check
- Passed
- 4 h ago, next any minute now
Reliability
Status and outage history · Atom feed · Watch with other listings
How to call it
GET https://api.aiskills402.com/v1/skills/chain-evidence-check/file
Each call costs $0.05 in USDC on Base, paid with the request over x402.
Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.
Example request
The listing has no example input.
GET https://api.aiskills402.com/v1/skills/chain-evidence-check/fileExample response
The provider's example. We can't check it without paying.
{
"file": {
"content": "<the SKILL.md file>",
"encoding": "utf-8",
"name": "SKILL.md"
},
"name": "Chain Evidence Check",
"ok": true,
"receipt": {
"settled": true,
"tx": "0x<settlement transaction>"
},
"redownload": {
"token": "<64 hex chars>",
"url": "<api>/v1/purchases/<token>"
},
"sha256": "<sha256 of SKILL.md>",
"skill": "chain-evidence-check",
"version": "1.0.0"
}Call it from code
The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.05.
curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://api.aiskills402.com/v1/skills/chain-evidence-check/file'
# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://api.aiskills402.com/v1/skills/chain-evidence-check/file' \
| grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decodeJavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
// Pays at most $0.05 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.05" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);
// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.05 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.aiskills402.com%2Fv1%2Fskills%2Fchain-evidence-check%2Ffile
const res = await pay("https://api.aiskills402.com/v1/skills/chain-evidence-check/file");
console.log(res.status, await res.text());Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client
# Pays at most $0.05 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.05"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))
with x402_requests(client) as session:
res = session.get("https://api.aiskills402.com/v1/skills/chain-evidence-check/file")
print(res.status_code, res.text)Security scan
No findings
We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.
Recent checks
| When | Result | HTTP | Time | Price |
|---|---|---|---|---|
| 4 h ago | Passed | 402 | 593 ms | $0.05 |
| 9 h ago | Passed | 402 | 804 ms | $0.05 |
| 14 h ago | Passed | 402 | 629 ms | $0.05 |
| 19 h ago | Passed | 402 | 451 ms | $0.05 |
| 24 h ago | Passed | 402 | 857 ms | $0.05 |
Show 10 older checks
| 28 h ago | Passed | 402 | 563 ms | $0.05 |
| 33 h ago | Passed | 402 | 735 ms | $0.05 |
| 38 h ago | Passed | 402 | 458 ms | $0.05 |
| 42 h ago | Passed | 402 | 157 ms | $0.05 |
| 46 h ago | Passed | 402 | 461 ms | $0.05 |
| 2 days ago | Passed | 402 | 1.1 s | $0.05 |
| 2 days ago | Passed | 402 | 686 ms | $0.05 |
| 2 days ago | Passed | 402 | 98 ms | $0.05 |
| 3 days ago | Passed | 402 | 843 ms | $0.05 |
| 3 days ago | Passed | 402 | 409 ms | $0.05 |