agentmods.dev

debug-webhooks

A troubleshooting workflow for webhooks in a Meta app. Webhooks are notifications that an app sends when something happens, such as a new event or data change.

In plain words
What is it for?
Use it to inspect Meta app webhook subscriptions, compare them with available topics, identify missing or incorrect setup, and send test payloads.
Why use it?
It helps find why expected notifications are not arriving by checking subscriptions, available topics, and test deliveries.

Skill for Claude CodeCodex

5 11d ago A scan 40 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/debug-webhooks
Any agent
npx skills add facebook/agentic-tools --skill debug-webhooks
Clone the repo
git clone --depth 1 https://github.com/facebook/agentic-tools

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,027 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 $0.00040 $0.01027
Opus 5 $0.00020 $0.00513
Sonnet 5 $0.00008 $0.00205
Haiku 4.5 $0.00004 $0.00103

Measured yesterday against content hash fd36100093b0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debug-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 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/debug-webhooks/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debug Webhooks

Diagnose and fix webhook delivery issues for a Meta app.

Workflow

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

  2. Get context. Ask the user for:

    • The app name or ID — if they give a name (or aren't sure of the ID), resolve it to an app_id via devtools_app_list (action list); if several apps match or it's ambiguous, show the candidates (name, ID, viewer role) and ask the user to pick
    • What's going wrong (not receiving events? wrong data? specific topic?)

  3. Inspect current state. Run in parallel:

    • devtools_webhook_list with action list_subscriptions — all active subscriptions
    • devtools_webhook_list with action list_topics — all available topics (for comparison)

  4. Diagnose. Check for common issues:

    No subscriptions found

    • The topic the user expects events from has no active subscription
    • Suggest using /webhook-setup to create one

    Subscription exists but no events received

    • Send a test payload: devtools_webhook_test with action test_send for the relevant topic and field
    • If test fails: callback URL may be down, unreachable, or not returning 200
    • If test succeeds but real events don't arrive: the issue is likely on the app side (permissions, page subscriptions, etc.)

    Wrong fields subscribed

    • Compare subscribed fields against what the user expects to receive
    • If fields are missing: use devtools_webhook_manage with action update_fields, passing the missing fields via add_fields
    • If extra fields cause noise: use devtools_webhook_manage with action update_fields, passing unwanted fields via remove_fields

    Multiple subscriptions on same topic

    • Flag potential conflicts or duplicate delivery

  5. Test delivery. For each relevant subscription:

    • Call devtools_webhook_test with action test_send
    • Report whether the test payload was accepted by the callback endpoint

Read the full file on GitHub · 84 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 · 84 lines · 40 tokens per session scan A fd36100093b0

Subscribe to this mod's changes

debug-webhooks is a skill published in the GitHub repository facebook/agentic-tools (5 stars, last pushed 11d ago), licensed MIT. It adds 40 tokens to every session and 1,027 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.

DebuggingProductivityTesting
Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

babysit-pr

Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…

openai/codex · 114 tokens

imagegen

Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output…

openai/codex · 113 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

next-cache-components-optimizer

Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…

vercel/next.js · 170 tokens