Skill: Webhook secure intake

Bundled execution of the Webhook secure intake workflow — The production ingest path for every incoming webhook: verify the provider signature (GitHub / Stripe / Shopify / Slack, constant-time, replay-window enforced), schema-validate the now-trusted body against the provider envelope, fingerprint the raw bytes for redelivery dedup, normalize the event timestamp to UTC + epoch, and redact PII before anything hits a log. Five pure-CPU tools — the accept-or-reject gate, run on every event. One x402 payment runs 5 underlying tools (webhook-verify, json-validate, hash, time-convert, redact); partial-success per step.

Input

Field	Type	Description
rawBody *	string	the raw webhook body exactly as received on the wire (signatures are over the raw bytes)
provider *	string	which provider signed the webhook: github | stripe | shopify | slack
secret *	string	the webhook signing secret from the provider dashboard (never echoed back)
signature *	string	the signature header value, with or without its scheme prefix (sha256= / v0= / t=...,v1=...)
timestamp	string	the provider timestamp header — required for stripe/slack replay protection (stripe's may ride in the signature's t= element)

Example output

{
  "pack": "webhook-intake",
  "args": {
    "rawBody": "{\"ref\":\"refs/heads/main\",\"before\":\"6113728f27ae82c7b1a177c8d03f9e96e0adf246\",\"after\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"repository\":{\"full_name\":\"acme/checkout-service\"},\"pusher\":{\"name\":\"alice\",\"email\":\"alice@example.com\"},\"head_commit\":{\"id\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"message\":\"fix: retry payment capture on 5xx\",\"timestamp\":\"2026-07-01T15:04:05Z\"}}",
    "provider": "github",
    "secret": "gh_hook_secret_demo_only",
    "signature": "sha256=45f74caa8f537323fd4fa022357ebc620cbcfb28a6dcd65b0f1da3646edf5c4a"
  },
  "steps": [
    {
      "slug": "webhook-verify",
      "ok": true,
      "result": {}
    },
    {
      "slug": "json-validate",
      "ok": true,
      "result": {}
    },
    {
      "slug": "hash",
      "ok": true,
      "result": {}
    },
    {
      "slug": "time-convert",
      "ok": true,
      "result": {}
    },
    {
      "slug": "redact",
      "ok": true,
      "result": {}
    }
  ],
  "summary": "5/5 steps succeeded"
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/skill/webhook-intake \
  -H "Content-Type: application/json" \
  -d '{"rawBody":"{\"ref\":\"refs/heads/main\",\"before\":\"6113728f27ae82c7b1a177c8d03f9e96e0adf246\",\"after\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"repository\":{\"full_name\":\"acme/checkout-service\"},\"pusher\":{\"name\":\"alice\",\"email\":\"alice@example.com\"},\"head_commit\":{\"id\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"message\":\"fix: retry payment capture on 5xx\",\"timestamp\":\"2026-07-01T15:04:05Z\"}}","provider":"github","secret":"gh_hook_secret_demo_only","signature":"sha256=45f74caa8f537323fd4fa022357ebc620cbcfb28a6dcd65b0f1da3646edf5c4a"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/skill/webhook-intake", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "rawBody": "{\"ref\":\"refs/heads/main\",\"before\":\"6113728f27ae82c7b1a177c8d03f9e96e0adf246\",\"after\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"repository\":{\"full_name\":\"acme/checkout-service\"},\"pusher\":{\"name\":\"alice\",\"email\":\"alice@example.com\"},\"head_commit\":{\"id\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"message\":\"fix: retry payment capture on 5xx\",\"timestamp\":\"2026-07-01T15:04:05Z\"}}",
    "provider": "github",
    "secret": "gh_hook_secret_demo_only",
    "signature": "sha256=45f74caa8f537323fd4fa022357ebc620cbcfb28a6dcd65b0f1da3646edf5c4a"
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits — a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=skill-webhook-intake")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/skill/webhook-intake", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"rawBody":"{\"ref\":\"refs/heads/main\",\"before\":\"6113728f27ae82c7b1a177c8d03f9e96e0adf246\",\"after\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"repository\":{\"full_name\":\"acme/checkout-service\"},\"pusher\":{\"name\":\"alice\",\"email\":\"alice@example.com\"},\"head_commit\":{\"id\":\"d6fde92930d4715a2b49857d24b940956b26d2d3\",\"message\":\"fix: retry payment capture on 5xx\",\"timestamp\":\"2026-07-01T15:04:05Z\"}}","provider":"github","secret":"gh_hook_secret_demo_only","signature":"sha256=45f74caa8f537323fd4fa022357ebc620cbcfb28a6dcd65b0f1da3646edf5c4a"}) });

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