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 ordinal-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/ordinal-webhooks)<a href="https://agentmods.dev/skills/hookdeck/webhook-skills/ordinal-webhooks"><img src="https://agentmods.dev/badge/skills/hookdeck/webhook-skills/ordinal-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/ordinal-webhooks"><img src="https://agentmods.dev/badge/skills/hookdeck/webhook-skills/ordinal-webhooks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00196 | $0.03762 |
| Opus 5.5 | $0.00078 | $0.01505 |
| Sonnet 5.5 | $0.00039 | $0.00752 |
| Haiku 4.5 | $0.00020 | $0.00376 |
Grade A, and why
ordinal-webhooks scanned grade A with 1 finding 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 18d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -X POST "https://app.tryordinal.com/api/v1/webhooks" \ How it starts
The opening of the file, as written. The whole thing — 272 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Ordinal Webhooks
Ordinal (tryordinal.com) is a social-media content
planning, approval and scheduling platform for marketing teams — LinkedIn and X posts,
campaigns, approval workflows and comment threads. App: https://app.tryordinal.com.
Docs: https://docs.tryordinal.com. REST API base: https://app.tryordinal.com/api/v1.
This is not Bitcoin Ordinals / inscriptions (
ord), not Ordinal Stats or Ordinal Labs, and not an "ordinal numbers" package. There is no official Ordinal npm or pip SDK — do not add one topackage.json/requirements.txt.
There Is No Signature — Do Not Write One
Ordinal does not sign webhook deliveries. Verified against the rendered docs
(introduction, event types, every per-event page, and the Create/Get/Update webhook API
reference): there is no signature header, no signing secret, no whsec_ key, no
timestamp header, no HMAC, and no Svix / Standard Webhooks headers. The Create webhook
response returns only id, name, url, topics, createdAt — no secret is ever
issued.
Do not invent X-Ordinal-Signature, Ordinal-Signature, webhook-signature, or any
crypto.createHmac / hmac.new path. A fabricated verifier rejects every real delivery.
The only authentication mechanism is a static custom header you configure yourself.
The webhook object has an optional headers field — documented verbatim as "Optional
custom headers to include in webhook requests" — a JSON object of header name → value
that Ordinal adds to every delivery. The recommended pattern:
- Generate a long random secret yourself (e.g.
openssl rand -hex 32). - Create or patch the webhook with that secret in
headers:"headers": { "X-Webhook-Secret": "<your secret>" }. The header name is your choice — it is not an Ordinal-defined header. These examples readx-webhook-secret, overridable viaORDINAL_WEBHOOK_SECRET_HEADER. - Compare the incoming header against
ORDINAL_WEBHOOK_SECRETin constant time and return401on mismatch or absence. - Fail closed: if
ORDINAL_WEBHOOK_SECRETis unset, reject (500) — never accept everything silently.
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 1.1 KB
- examples/express/package.json 457 B
- examples/express/README.md 2.9 KB
- examples/express/src/index.js 13 KB runs code
- examples/express/test/webhook.test.js 19 KB runs code
- examples/fastapi/.env.example 1.1 KB
- examples/fastapi/main.py 12 KB runs code
- examples/fastapi/README.md 3.0 KB
- examples/fastapi/requirements.txt 82 B
- examples/fastapi/test_webhook.py 21 KB runs code
- examples/nextjs/.env.example 1.1 KB
- examples/nextjs/app/webhooks/ordinal/route.ts 12 KB runs code
- examples/nextjs/package.json 578 B
- examples/nextjs/README.md 2.8 KB
- examples/nextjs/test/webhook.test.ts 19 KB runs code
- examples/nextjs/vitest.config.ts 162 B runs code
- references/overview.md 9.3 KB
- references/setup.md 7.7 KB
- references/verification.md 9.9 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.
- 18d ago First seen · 272 lines · 196 tokens per session scan A 9648e0439fda
ordinal-webhooks is a skill published in the GitHub repository hookdeck/webhook-skills (92 stars, last pushed yesterday), licensed MIT. It adds 196 tokens to every session and 3,762 once invoked, about $0.0008 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-29.
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