extension-email-verification

extension-email-verification is a skill for Claude Code, Codex from caffeinelabs/skills. It costs 25 tokens per session (1,256 once invoked), scanned A, original, Apache-2.0.

An email-address verification tool that sends a link a recipient can click to prove they control the address. It records which addresses have been verified.

In plain words
What is it for?
Use it for sign-up confirmation and other flows that require a verified email address. Check the recorded verification state before allowing actions that depend on it.
Why use it?
It gives an application a consistent way to confirm email ownership and check verification status without maintaining a separate status field on user profiles.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for sign-up confirmation and other flows that require a verified email address. Check the recorded verification state before allowing actions that depend on it.

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Install with agentmods
npx agentmods add skills/caffeinelabs/skills/extension-email-verification
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.

Any agent
npx skills add caffeinelabs/skills --skill extension-email-verification
Clone the repo
git clone --depth 1 https://github.com/caffeinelabs/skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for extension-email-verification

README.md
[![agentmods](https://agentmods.dev/badge/skills/caffeinelabs/skills/extension-email-verification/github.svg)](https://agentmods.dev/skills/caffeinelabs/skills/extension-email-verification)
Your own site
<a href="https://agentmods.dev/skills/caffeinelabs/skills/extension-email-verification"><img src="https://agentmods.dev/badge/skills/caffeinelabs/skills/extension-email-verification/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.

agentmods 80×15 button for extension-email-verification

Your own site · 80×15
<a href="https://agentmods.dev/skills/caffeinelabs/skills/extension-email-verification"><img src="https://agentmods.dev/badge/skills/caffeinelabs/skills/extension-email-verification.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,256 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
  • Socket pass 17 Aug 2026
  • Snyk pass 17 Aug 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 $0.00025 $0.01256
Opus 5 $0.00013 $0.00628
Sonnet 5 $0.00005 $0.00251
Haiku 4.5 $0.00003 $0.00126

Measured yesterday against content hash c3c049bbad8c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

extension-email-verification 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.

skills/extension-email-verification/SKILL.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Email — Verification

Email verification extension for Caffeine AI.

Overview

This skill adds email address verification via a click-to-verify link. The MixinEmailVerification handles the verification callback; verifiedEmails tracks verified addresses.

Backend

This component is for sending an email to users with a verification link which the user can click to prove they own the email address.

To check if an email address has been verified

Use the prefabricated module mo:caffeineai-email-verification/verifiedEmails.mo which cannot be modified.

module {
  public type State = {
    var verifiedEmails : Set.Set<Text>;
  };

  public func new() : State {
    {
      var verifiedEmails = Set.empty<Text>();
    };
  };

  public func contains(state : State, email : Text) : Bool;

  public func iter(state : State) : Iter.Iter<Text>;

  public func size(state : State) : Nat;
};

To check whether an email is verified use the contains function. Do NOT try to track the email verification status independently by storing it against the user profile.

To handle the verification link

Use the prefabricated module mo:caffeineai-email-verification/verificationMixin.mo which cannot be modified.

The MixinEmailVerification handles calls to the verification link to verify an email address.

import MixinEmailVerification "mo:caffeineai-email-verification/verificationMixin";

For sending users a verification email

  • This extension depends on the extension-email for sending emails.
  • Use the sendVerificationEmail function.
  • It returns a SendResult which is #ok if the email is sent successfully otherwise #err(error) with the error text.
  • Each recipient receives an individual email with a specific verification link for them
  • The htmlBody MUST contain the placeholder text {{VERIFICATION_URL}}

Read the full file on GitHub · 179 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 Changed · +28 lines c3c049bbad8c
  2. 8d ago First seen · 151 lines · 25 tokens per session scan A cbafd3149b94

Subscribe to this mod's changes

extension-email-verification is a skill published in the GitHub repository caffeinelabs/skills (0 stars, last pushed today), licensed Apache-2.0. It adds 25 tokens to every session and 1,256 once invoked, about $0.0001 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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