ToolVet
77trust / 100

Deps Check

by Preflight in Developer tools

x402 APIPassing, checked 2 h ago

Call before installing packages suggested by a language model. Returns, for each npm or PyPI package name, whether it actually exists in the registry, whether it is deprecated or yanked, and — when the name is not found — the closest real package names. Catches hallucinated dependencies (slopsquatting) before an agent installs them. Never inspects package contents and never returns a safety verdict.

POST https://preflight402.com/v1/deps/check

Last 30 days

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Status and outage history · Atom feed

Uptime
100%
Response time
776 ms typical, 1.1 s slowest 5%
Last check
2 h ago
Next check
any minute now

How to call it

POST https://preflight402.com/v1/deps/check

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

From the listing.

POST https://preflight402.com/v1/deps/check
content-type: application/json

{
  "ecosystem": "npm",
  "packages": [
    "left-pad"
  ]
}

Parameters

ParameterTypeRequiredDescription
ecosystemstringYes One of: npm, pypi, crates.
packagesarray of stringYes

Example response

The provider's example. We can't check it without paying.

{
  "checked_at": "2026-09-02T21:40:00Z",
  "ecosystem": "npm",
  "results": [
    {
      "exists": false,
      "name": "jscodeshift-react",
      "official_url": "https://www.npmjs.com/package/jscodeshift-react",
      "verdict": "not_found"
    }
  ]
}

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 -X POST 'https://preflight402.com/v1/deps/check' \
  -H 'content-type: application/json' \
  --data-raw '{"ecosystem":"npm","packages":["left-pad"]}'

# 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 - -X POST 'https://preflight402.com/v1/deps/check' \
  -H 'content-type: application/json' \
  --data-raw '{"ecosystem":"npm","packages":["left-pad"]}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: 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%2Fpreflight402.com%2Fv1%2Fdeps%2Fcheck&method=POST
const res = await pay("https://preflight402.com/v1/deps/check", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "ecosystem": "npm",
    "packages": [
      "left-pad"
    ]
  }),
});
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.post(
        "https://preflight402.com/v1/deps/check",
        json={
            "ecosystem": "npm",
            "packages": [
                "left-pad",
            ],
        },
    )
    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

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