Trail

Multi-touch attribution tracker. Rebuilds the full visitor journey before a form submission — without a CRM, without a dashboard.

The interface is your AI agent.

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What it does

Trail drops a lightweight script (~3kb) on your site. It tracks every session a visitor has before converting, stores the channel for each one, and links them to a lead ID when a form is submitted.

Session 1 — google_ads        (clicked a Google Ad)
Session 2 — direct            (came back directly)
Session 3 — google_profile    (clicked the Google Business link)
               ↓
         form submitted → lead linked to all 3 touchpoints

Query the data through an MCP server — ask your AI agent "where are my leads coming from?" and get a real answer.

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Channel detection

Signal	Channel
gclid	google_ads
fbclid	facebook_ads
li_fat_id	linkedin_ads
ttclid	tiktok_ads
utm_source=X	exact value (e.g. google_profile, newsletter)
Referrer = search engine	organic_search
Referrer = social network	organic_social
Nothing	direct

UTM parameters are persisted in sessionStorage — if a visitor lands with UTMs then navigates to /contact, the channel is preserved when they submit the form.

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Installation

Option 1 — Self-hosted (Node.js + SQLite)

npm install -g @trail/server
trail

Starts on http://localhost:3000. SQLite database created automatically at ~/.trail/trail.db.

Add the tracker to your site:

<script src="http://localhost:3000/t.js"
  data-account-id="your-site"
  async defer></script>

Option 2 — Cloudflare Workers + D1

Deploy your own instance on Cloudflare Workers with a D1 database.

git clone https://github.com/SilverBackBase/Trail.git
cd trail
pnpm install

Create the D1 database:

npx wrangler d1 create trail
# copy the database_id into packages/api/wrangler.toml and packages/mcp/wrangler.toml

Apply migrations:

npx wrangler d1 execute trail --file=packages/api/migrations/001_init.sql --remote

Deploy:

cd packages/api && npx wrangler deploy
cd packages/mcp && npx wrangler deploy

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GTM installation

If you use Google Tag Manager, create a Custom HTML tag with:

<script>window.TRAIL_ACCOUNT_ID = "your-site";</script>
<script src="https://your-api.workers.dev/t.js" async defer></script>

Set trigger to All Pages.

GTM strips data-* attributes from injected scripts — use window.TRAIL_ACCOUNT_ID instead.

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MCP server

Trail exposes an MCP server so your AI agent can query attribution data directly.

Add to your ~/.claude.json:

"trail": {
  "type": "http",
  "url": "https://your-mcp.workers.dev/mcp"
}

Available tools:

Tool	Description
trail_create_account	Create a client account, get the tracker snippet
trail_list_accounts	List all accounts
trail_get_journey	Full touchpoint journey for a lead
trail_get_report	Attribution report by channel
trail_get_top_paths	Most common multi-touch paths
trail_get_channel_performance	Visitors / leads / conversions per channel

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Packages

packages/
  tracker/   Browser script — visitor ID, session detection, channel capture
  api/       HTTP API — receives touchpoints, stores to DB
  mcp/       MCP server — exposes attribution tools to AI agents

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Stack

• Tracker — vanilla TypeScript, compiled to ~3kb IIFE via esbuild
• API — Hono (runs on Cloudflare Workers or Node.js)
• Database — Cloudflare D1 (cloud) or SQLite via better-sqlite3 (self-hosted)
• MCP — @modelcontextprotocol/sdk with stateless Streamable HTTP transport

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License

MIT — part of the SilverBackBase ecosystem.