HubSpot Contacts AEO Source: tagging every AI-referred lead

What this does

Every contact that arrives from ChatGPT, Perplexity, Claude, or Gemini gets tagged at the moment of creation with a clean, queryable ai_source value — not dumped into 'Direct' or 'Other Campaigns' where HubSpot defaults it. Lantern handles the three hard cases: (1) direct clicks with document.referrer intact, (2) mobile referrer stripped sessions, (3) sessions that hit a middle page before signing up (UTM on first hit is preserved across navigations).

How Lantern fits

Lantern's JS snippet runs before HubSpot's tracking code and does three things: detects AI hostname in document.referrer, rewrites the URL with utm_source=chatgpt&utm_medium=ai-referral via history.replaceState, stores the source in a first-party cookie with 30-day TTL. When HubSpot's tracking code fires, it sees the UTM and picks up ai_source correctly. The cookie handles the case where a user lands from ChatGPT, browses three pages, then converts on page 4 (referrer is lost but cookie persists).

Setup preview

The snippet Lantern installs is ~1.5KB minified and runs synchronously before HubSpot's _hsq queue initializes. It checks a whitelist of ~30 AI engine hostnames (chat.openai.com, chatgpt.com, perplexity.ai, claude.ai, gemini.google.com, and variations), matches them to engine names, writes the UTM, and sets the lantern_ai_src cookie. If the hostname isn't in the list, the snippet is a no-op — it won't alter normal referrer traffic.

// Lantern AI source detection — inline before HubSpot tracking
(function() {
  var AI_HOSTS = {
    'chat.openai.com': 'chatgpt',
    'chatgpt.com': 'chatgpt',
    'openai.com': 'chatgpt',
    'perplexity.ai': 'perplexity',
    'www.perplexity.ai': 'perplexity',
    'claude.ai': 'claude',
    'anthropic.com': 'claude',
    'gemini.google.com': 'gemini',
    'bard.google.com': 'gemini'
  };

  function getEngine() {
    // 1. Check first-party cookie (persists across pages)
    var c = document.cookie.match(/lantern_ai_src=([^;]+)/);
    if (c) return c[1];

    // 2. Check document.referrer
    try {
      var host = new URL(document.referrer).hostname;
      if (AI_HOSTS[host]) return AI_HOSTS[host];
    } catch (e) {}

    return null;
  }

  var engine = getEngine();
  if (!engine) return;

  // Set cookie (30 days)
  document.cookie = 'lantern_ai_src=' + engine + ';max-age=2592000;path=/;SameSite=Lax';

  // Rewrite URL with UTMs if not already present
  var url = new URL(window.location.href);
  if (!url.searchParams.has('utm_source')) {
    url.searchParams.set('utm_source', engine);
    url.searchParams.set('utm_medium', 'ai-referral');
    window.history.replaceState({}, '', url.toString());
  }
})();

Where this fits in the bigger picture

This page describes one specific surface inside HubSpot where Lantern's AEO pipeline attribution plugs in. The full integration stitches together across HubSpot Contacts, Deals, Workflows, Lists, Reports, Forms, CMS, and the Marketing/Sales/Service Hub stack. If you're evaluating where to start, the comparison hub has side-by-side comparisons of Lantern against Profound, Scrunch, Peec AI, AthenaHQ, and HubSpot's own AEO product — scored on the dimensions that matter for a CMO buyer (CRM integration depth, reporting quality, prompt-scaling economics).

If you're about to walk this work into a renewal review or budget conversation, the CFO's Guide to AEO Budget Defense has the memo template, the five-slide deck structure, the attribution-math cheat sheet, and the three most-common CFO objections with counter-arguments. It's the long-form companion that translates the technical HubSpot setup on this page into a defensible dollar number for finance.