YALC-the-GTM-operating-system: Skill for Claude Code

.claude/skills/fullenrich-plg-reverse-lookup/SKILL.md

fullenrich-plg-reverse-lookup is a skill for Claude Code from Othmane-Khadri/YALC-the-GTM-operating-system. It costs 0 tokens per session (1,270 once invoked), scanned A, original, MIT.

A process for identifying people and companies from free-trial signup email addresses using FullEnrich, a data-enrichment service. It supports a CSV batch workflow or a hosted webhook that receives an email and records the result.

In plain words
What is it for?
Use it to enrich a signup CSV, deploy a webhook for incoming emails, obtain a person’s LinkedIn profile and company, or forward the enriched record to another URL.
Why use it?
It removes the manual work of researching who a signup belongs to while the trial is still recent. It does not capture signup events itself; your product or another system must send the data.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is Othmane-Khadri/YALC-the-GTM-operating-system's own configuration. It tells Claude Code how to work on YALC-the-GTM-operating-system itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything YALC-the-GTM-operating-system configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Othmane-Khadri/YALC-the-GTM-operating-system. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Othmane-Khadri/YALC-the-GTM-operating-system/main/.claude/skills/fullenrich-plg-reverse-lookup/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Othmane-Khadri/YALC-the-GTM-operating-system

Made for: Claude Code.

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README.md
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Your own site · 80×15
<a href="https://agentmods.dev/skills/othmane-khadri/yalc-the-gtm-operating-system/fullenrich-plg-reverse-lookup"><img src="https://agentmods.dev/badge/skills/othmane-khadri/yalc-the-gtm-operating-system/fullenrich-plg-reverse-lookup.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,270 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00000 $0.01270
Opus 5 $0.00000 $0.00635
Sonnet 5 $0.00000 $0.00254
Haiku 4.5 $0.00000 $0.00127

Measured 12d ago against content hash bed57f33cfc5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

fullenrich-plg-reverse-lookup 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 12d ago.

The scan reads SKILL.md. This mod also ships 7 executable files (api/fullenrich-callback.mjs, api/signup.mjs, api/webhook.mjs, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/fullenrich-plg-reverse-lookup/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FullEnrich PLG Reverse Lookup

When a free trial signup hits your product, you have ~5 minutes before they cool off. This skill turns a signup email into an identified person + LinkedIn profile + company in real time, using FullEnrich's reverse email lookup.

Two install paths in one repo:

  • Path A (CLI batch): point it at a signups.csv, get an enriched JSON back. Cron-friendly.
  • Path B (hosted webhook): deploy the included api/ folder to any Vercel-compatible host. Receives POST { email }, runs reverse lookup, writes the enriched record to a JSONL log and optionally forwards it to any URL you specify. Pure FullEnrich output; wire downstream to whatever stack you run.

When This Skill Applies

  • "set up FullEnrich reverse lookup for trial signups"
  • "PLG enrichment webhook"
  • "who are these emails"
  • "identify free trial signups via FullEnrich"
  • "deploy a Vercel webhook for trial signups"

What This Skill Does NOT Do

  • Does not capture signup events itself. You wire your product's signup hook (your backend, your auth provider, your payment processor, whatever fires when a new user is created) to either path A's CSV or path B's webhook URL.
  • Does not write outreach copy.
  • Does not spend credits without explicit user approval (CLI mode). See "Credit safety contract" below.

Credit safety contract (MANDATORY)

This skill spends FullEnrich credits, which cost real money. Safeguards (CLI mode):

  1. Always shows current balance before doing anything.
  2. Always shows estimated cost of the run.
  3. --max-credits N ceiling (default 100) — auto-trims the email list to fit.
  4. Hard-approval prompt — blocks on stdin until the user types yes. Non-TTY without --yes aborts.
  5. --dry-run mode — parses + dedupes without spending a credit.

Webhook mode is different. It runs unattended in production. Built-in protections there:

  • MAX_CREDITS_PER_DAY env var (default 200) — webhook short-circuits with HTTP 429 once exceeded, written to a lookup-counter.json shadow file in /tmp for cold-start safety.
  • WEBHOOK_DRY_RUN=1 env var — webhook validates payload and logs intent but does NOT call FullEnrich. Use this for the first 24 hours after deploy.
  • Each webhook invocation logs the running daily total to stdout. Set up a Vercel log alert if you want stricter control.

Read the full file on GitHub · 96 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. 12d ago First seen · 96 lines · 0 tokens per session scan A bed57f33cfc5

Subscribe to this mod's changes

fullenrich-plg-reverse-lookup is a skill published in the GitHub repository Othmane-Khadri/YALC-the-GTM-operating-system (301 stars, last pushed 22d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,270 tokens. 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 2026-08-30.