agentmods.dev

webhook-setup

A guided setup process for webhooks in a Meta app. Webhooks are notifications that send your application information when something happens, such as an event involving a page, user, Instagram account, or WhatsApp Business account.

In plain words
What is it for?
Finding available webhook topics and fields, reviewing current subscriptions, adding subscriptions, and verifying them with a test notification.
Why use it?
Setting up webhooks requires finding the right event topics, checking existing subscriptions, and testing that notifications arrive. The process organizes those configuration steps.

Skill for Claude CodeCodex

5 11d ago A scan 46 tokens original MIT
View the source file facebook/agentic-tools
Install

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.

agentmods
npx agentmods add skills/facebook/agentic-tools/webhook-setup
Any agent
npx skills add facebook/agentic-tools --skill webhook-setup
Clone the repo
git clone --depth 1 https://github.com/facebook/agentic-tools

Made for: Claude Code, Codex.

Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 804 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00046 $0.00804
Opus 5 $0.00023 $0.00402
Sonnet 5 $0.00009 $0.00161
Haiku 4.5 $0.00005 $0.00080

Measured yesterday against content hash 7ca5bc9dcfa7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

webhook-setup 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 yesterday.

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.

plugins/devtools/skills/webhook-setup/SKILL.md · 57 lines

How it starts

The opening of the file, as written. The whole thing — 57 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Webhook Setup

Interactive wizard to configure webhooks on a Meta app from scratch.

Workflow

  1. Start tracking. Before any other work, call devtools_skill_invocation with action start and skill_name webhook-setup. Pass skill_name webhook-setup on every devtools_* tool call in the following steps.

  2. Identify the app. Ask the user for the app name or ID. If they give a name (or aren't sure of the ID), call devtools_app_list (action list) and resolve it to an app_id — match the name case-insensitively. If several apps match or it's ambiguous, show the candidates (name, ID, viewer role) and ask the user to pick. If they give a numeric ID, use it directly.

  3. Check existing state. Run in parallel:

    • devtools_webhook_list with action list_topics — show all available webhook topics
    • devtools_webhook_list with action list_subscriptions — show what's already subscribed

  4. Present the options. Show the user:

    • Available topics (e.g., page, user, instagram, whatsapp_business_account)
    • Which topics already have active subscriptions
    • For each topic, list the subscribable fields

  5. Collect subscription details. Ask the user for:

    • Topic — which webhook topic to subscribe to
    • Fields — which fields within that topic (e.g., feed, messages)
    • Callback URL — their HTTPS endpoint (must be live and pass Meta's verification challenge)
    • Verify token — the token their server expects for the verification handshake

  6. Subscribe. Call devtools_webhook_manage with action subscribe:

    • Pass topic, fields, callback_url, verify_token
    • If the subscription fails, explain the likely cause:
      • Callback URL not reachable → server must be running and publicly accessible
      • Verification failed → verify token mismatch or endpoint not responding to GET challenge
      • Invalid fields → check field names against the topic's available fields

  7. Verify with a test payload. After successful subscription:

    • Call devtools_webhook_test with action test_send for one of the subscribed fields
    • Confirm whether the test payload was delivered
    • If test fails, suggest checking server logs and endpoint configuration

Read the full file on GitHub · 57 lines

Changes

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.

  1. yesterday First seen · 57 lines · 46 tokens per session scan A 7ca5bc9dcfa7

Subscribe to this mod's changes

webhook-setup is a skill published in the GitHub repository facebook/agentic-tools (5 stars, last pushed 11d ago), licensed MIT. It adds 46 tokens to every session and 804 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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