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 agentmods add skills/hookdeck/webhook-skills/frontapp-webhooksnpx skills add hookdeck/webhook-skills --skill frontapp-webhooksgit clone --depth 1 https://github.com/hookdeck/webhook-skillsWhat 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 | $0.00071 | $0.01404 |
| Opus 5 | $0.00036 | $0.00702 |
| Sonnet 5 | $0.00014 | $0.00281 |
| Haiku 4.5 | $0.00007 | $0.00140 |
Grade A, and why
frontapp-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 2d 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
80% identical to adyen-webhooks — 165 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 — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Front Webhooks
When to Use This Skill
- Setting up Front (Frontapp) application webhook handlers
- Debugging Front
X-Front-Signatureverification failures - Responding to the Front
X-Front-Challengesubscription validation request - Understanding Front event types (
inbound_received,outbound_sent,conversation_moved,assignee_changed,tag_added,new_comment_added) and payloads
Verification (core)
Front application webhooks have no official server SDK, so verify manually.
Front signs X-Front-Request-Timestamp + ":" + rawBody with HMAC-SHA256 (key = your
app's signing key), base64-encoded, delivered in the X-Front-Signature header. Use the
raw request body — never JSON.parse before verifying.
const crypto = require('crypto');
function verifyFrontSignature(rawBody, timestamp, signature, secret) {
const hmac = crypto.createHmac('sha256', secret);
hmac.update(timestamp + ':');
hmac.update(rawBody); // Buffer/string of the raw HTTP body
const expected = hmac.digest('base64');
try {
return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
} catch {
return false; // length mismatch = invalid
}
}
On subscription, Front first sends a validation request carrying an X-Front-Challenge
header. Reply within 10s with HTTP 200 echoing the value — {"challenge": "<value>"}
(JSON), challenge=<value> (form), or the raw value (text/plain).
For complete handlers with the challenge handshake, event dispatch, and tests, see:
Common Event Types
Front webhook payloads carry the event name in the top-level type field.
Event type |
Triggered When |
|---|---|
inbound_received |
Inbound message received |
outbound_sent |
Outbound message sent |
conversation_moved |
Conversation moved to another inbox |
message_delivery_failed |
Outbound message bounced / delivery failed |
conversation_archived |
Conversation archived |
conversation_reopened |
Conversation reopened |
conversation_deleted |
Conversation deleted |
conversation_restored |
Conversation restored |
conversation_snoozed |
Conversation snoozed |
conversation_snooze_expired |
Snooze expired |
new_comment_added |
Comment added to a conversation |
assignee_changed |
Assignee changed |
tag_added |
Tag added to a conversation |
tag_removed |
Tag removed from a conversation |
link_added |
Link added to a conversation |
link_removed |
Link removed from a conversation |
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 173 B
- examples/express/package.json 369 B
- examples/express/README.md 1.1 KB
- examples/express/src/index.js 4.1 KB runs code
- examples/express/test/webhook.test.js 4.6 KB runs code
- examples/fastapi/.env.example 104 B
- examples/fastapi/main.py 3.7 KB runs code
- examples/fastapi/README.md 1.3 KB
- examples/fastapi/requirements.txt 82 B
- examples/fastapi/test_webhook.py 5.1 KB runs code
- examples/nextjs/.env.example 104 B
- examples/nextjs/app/webhooks/frontapp/route.ts 3.6 KB runs code
- examples/nextjs/package.json 481 B
- examples/nextjs/README.md 1.2 KB
- examples/nextjs/test/webhook.test.ts 4.5 KB runs code
- examples/nextjs/vitest.config.ts 140 B runs code
- references/overview.md 4.1 KB
- references/setup.md 3.2 KB
- references/verification.md 4.3 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.
- 2d ago First seen · 126 lines · 71 tokens per session scan A a98554d8c157
frontapp-webhooks is a skill published in the GitHub repository hookdeck/webhook-skills (84 stars, last pushed 5d ago), licensed MIT. It adds 71 tokens to every session and 1,404 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 80% identical to adyen-webhooks, differing in 165 lines, and is treated as a copy.
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