Framer
Framer forms are React-controlled, which the tag handles via React's value setter. Framer also lets you set a field's Name, so the cleanest path is name-based: name a hidden field to match your field map. The [mtk:…] token works too, as a fallback.
Add the tag to your site
In the Framer editor, open Project Settings (top-left) → General → Custom Code. Paste the loader into End of <head> tag, then Publish.
<script src="https://attr.boggsmtk.com/v1/tag.js?k=YOUR_LICENSE_KEY"></script>
Swap YOUR_LICENSE_KEYfor the client's key from the dashboard.
Put it in the <head> directly, not in Google Tag Manager. When GTM is blocked — an ad blocker, a privacy browser, a consent banner the visitor never accepts — nothing inside the container fires, and a tag that lives in GTM never loads. That lead arrives with empty attribution fields. Loaded straight from the <head>, the tag runs whether or not GTM does. A GTM Custom HTML tag on all pages still works if the <head> is genuinely off-limits, but treat it as the fallback, and expect to lose the leads whose browser blocks the container.
Add a hidden field to the form
Select your form, then add an input for each value you want to capture. In the input's properties on the right, set the field's Name to exactly the HTML Name from your field map (e.g. mtk_first_source). To keep it out of view, hide the layer (or move it off-canvas) — it still submits.
Fallback: if you can't set a usable name, put the [mtk:…]token in the field's default/placeholder value instead — the tag fills it by value.
Publish
Publish the site. The tag populates the field on load and again at submit, so attribution rides along with the lead.