Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add hookdeck/webhook-skills --skill github-webhooksgit clone --depth 1 https://github.com/hookdeck/webhook-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/hookdeck/webhook-skills/github-webhooks)<a href="https://agentmods.dev/skills/hookdeck/webhook-skills/github-webhooks"><img src="https://agentmods.dev/badge/skills/hookdeck/webhook-skills/github-webhooks/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hookdeck/webhook-skills/github-webhooks"><img src="https://agentmods.dev/badge/skills/hookdeck/webhook-skills/github-webhooks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00040 | $0.01446 |
| Opus 5.5 | $0.00016 | $0.00578 |
| Sonnet 5.5 | $0.00008 | $0.00289 |
| Haiku 4.5 | $0.00004 | $0.00145 |
Grade A, and why
github-webhooks scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
81% identical to adyen-webhooks — 163 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GitHub Webhooks
When to Use This Skill
- Setting up GitHub webhook handlers
- Debugging signature verification failures
- Understanding GitHub event types and payloads
- Handling push, pull request, or issue events
Verification (core)
GitHub signs the raw body with HMAC-SHA256 keyed on your webhook secret and sends the digest in X-Hub-Signature-256 formatted as sha256=<hex>. Use X-Hub-Signature-256 (not the legacy SHA-1 X-Hub-Signature), pass the raw body, and compare timing-safe.
Node:
const crypto = require('crypto');
function verify(rawBody, signatureHeader, secret) {
const [algo, sig] = (signatureHeader || '').split('=');
if (algo !== 'sha256' || !sig) return false;
const expected = crypto.createHmac('sha256', secret).update(rawBody).digest('hex');
try {
return crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected));
} catch {
return false;
}
}
Python:
import hmac, hashlib
def verify(raw_body: bytes, signature_header: str, secret: str) -> bool:
algo, _, sig = (signature_header or "").partition("=")
if algo != "sha256" or not sig:
return False
expected = hmac.new(secret.encode(), raw_body, hashlib.sha256).hexdigest()
return hmac.compare_digest(sig, expected)
For complete handlers with route wiring, event dispatch, and tests, see:
Common Event Types
| Event | Description |
|---|---|
push |
Commits pushed to branch |
pull_request |
PR opened, closed, merged, etc. |
issues |
Issue opened, closed, labeled, etc. |
release |
Release published |
workflow_run |
GitHub Actions workflow completed |
ping |
Test event when webhook created |
For full event reference, see GitHub Webhook Events
Important Headers
| Header | Description |
|---|---|
X-Hub-Signature-256 |
HMAC SHA-256 signature (use this, not sha1) |
X-GitHub-Event |
Event type (push, pull_request, etc.) |
X-GitHub-Delivery |
Unique delivery ID |
What ships with it
19 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- examples/express/.env.example 110 B
- examples/express/package.json 369 B
- examples/express/README.md 912 B
- examples/express/src/index.js 3.9 KB runs code
- examples/express/test/webhook.test.js 4.9 KB runs code
- examples/fastapi/.env.example 110 B
- examples/fastapi/main.py 3.0 KB runs code
- examples/fastapi/README.md 869 B
- examples/fastapi/requirements.txt 82 B
- examples/fastapi/test_webhook.py 5.6 KB runs code
- examples/nextjs/.env.example 110 B
- examples/nextjs/app/webhooks/github/route.ts 2.8 KB runs code
- examples/nextjs/package.json 478 B
- examples/nextjs/README.md 708 B
- examples/nextjs/test/webhook.test.ts 3.7 KB runs code
- examples/nextjs/vitest.config.ts 140 B runs code
- references/overview.md 2.7 KB
- references/setup.md 2.8 KB
- references/verification.md 4.8 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 132 lines · 40 tokens per session scan A 3bd595dfb116
github-webhooks is a skill published in the GitHub repository hookdeck/webhook-skills (92 stars, last pushed today), licensed MIT. It adds 40 tokens to every session and 1,446 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 81% identical to adyen-webhooks, differing in 163 lines, and is treated as a copy.
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