LetterCompany
NewMCP server, CLI and API, all free→Lettervisit · Analytics for your other audience

Track how often Claude, ChatGPT and Perplexity read your site—for free. And the best part? The data is accessible via API, MCP, or a CLI.

Get the free scriptSee how it works

Free forever · One script tag · MCP, CLI and API included

Watch it visit

What happens when an assistant reads your site

  1. 01

    A buyer asks Claude.

    They never open your site. Their assistant does, on their behalf.

  2. 02

    Claude opens your page.

    Claude-User fetches /pricing to answer them, right now.

  3. 03

    Lettervisit names it.

    Which agent, why it came, and a check against the vendor's published IP ranges.

  4. 04

    And your agent can ask.

    Every visit is one tool call away, over MCP, the CLI or the API.

Who's at the door

Every visit, named, verified, and sorted by why.

Lettervisit sorts user-agents of LLMs from scrapers so that you can only focus on the bot traffic that matters.

$0
Free, forever
2 min
To install
4 reasons
Every visit sorted by why
3 ways in
MCP, CLI and API
01

Answering a user

Someone asked Claude or ChatGPT a question and it opened your page to answer. The closest thing to a human visit, and the one to watch.

ChatGPT-UserClaude-UserPerplexity-User
02

Search index

Building the index an assistant searches before it answers. If these stop coming, you stop being cited.

OAI-SearchBotClaude-SearchBotPerplexityBot
03

Training crawl

Collecting pages for the next model. Slow, broad, and the one most robots.txt rules are written for.

GPTBotClaudeBot
04

Browser agent

An agent driving a real browser: clicking, filling forms, comparing plans. It runs your JavaScript, so the script sees it directly.

ChatGPT agentClaude for ChromeComet
The hidden layer

Already at your door.

Assistants read your site all day, answering questions you never see. Move the light to see who came, what they read, and why.

How it works

Two minutes to install. Then ask.

The script catches agents that drive a browser.

  1. 1

    Paste the script

    One tag in your <head>. It sees browser agents like ChatGPT agent and Comet.

    • ✓ Script found acme.com
    • ✓ Site verified 0.8s
    • → Watching the door
  2. 2

    Ask your agent

    Open the dashboard, or skip it: query every visit from Claude, ChatGPT or a terminal.

    $ npx letterstory/letterstory visits --agent claude --since 7d
Citations

See which answers send people to you.

When ChatGPT, Claude or Perplexity cites your page and someone clicks through, Lettervisit counts it, next to the agent visits that came before it.

De-anonymization

Then see who they are.

The agents read first. Then their answers send people. Turn on de-anonymization and Lettervisit names the companies and people behind those visits, and what they read.

  • 01

    The company and the person

    Which company visited, and who, when they can be identified.

  • 02

    What sent them

    Next to the answer that cited you, and the pages they read once they arrived.

  • 03

    The first 10 are free

    Your first 10 identified visitors cost nothing. Book a call for more.

Get the free scriptBook a call →
MCP · CLI · API

Your agents can read it too.

A dashboard is for looking. Everything in it is also a tool call, a command and an endpoint, so the agent you already work with can answer questions about the agents visiting you.

  • MCPA remote MCP server for Claude, ChatGPT and anything else that speaks it.
  • CLInpx letterstory/letterstory for scripts, cron jobs and CI. Every command takes --json.
  • APIA REST API with keys per site, cursors, and the same filters as the dashboard.
// claude_desktop_config.json, or any MCP client
{ "mcpServers": { "lettervisit": {
    "url": "https://lettervisit.com/mcp"
} } }

you ›Which of our docs did ChatGPT read this week that Claude didn't?
claude ›lettervisit.compare_agents(since: "7d", path: "/docs/*")
Three pages, all under /docs/sdks. ChatGPT-User opened them while answering users; Claude-User hasn't visited that section at all.
Pricing

Free. Not a trial.

Lettervisit will remain free, forever.

Also want de-anonymized visitors? First 10 identified visitors free. Book a call for more.

Lettervisit$0forever, for every site you runGet the free script
  • Every AI agent, verified against vendor IP ranges
  • See which ChatGPT and Claude answers send people to you
  • Script tag plus edge middleware
  • Live feed and dashboard
  • Remote MCP server
  • CLI with --json on every command
  • REST API and per-site keys
  • Unlimited sites and teammates
  • Your data exports any time
FAQ

Questions, answered.

Can a script tag really see AI agents?

Some of them. Agents that drive a real browser, like ChatGPT agent or Comet, run your JavaScript, so the script sees them. Crawlers and fetchers like ClaudeBot or ChatGPT-User only read the HTML, which is why Lettervisit also ships a one-line middleware for the edge. Install both and you see both.

How do you know a visit is really from Claude or ChatGPT?

A user-agent string is easy to fake. Lettervisit checks each crawler and fetcher against the IP ranges its vendor publishes, and labels a visit verified only when they match. Browser agents run on ordinary machines and can't be checked that way, so they are marked detected instead.

How do you know someone came from a ChatGPT or Claude answer?

When the answer engine marks the link as coming from it: ChatGPT adds utm_source=chatgpt.com to the sources it cites, and some engines pass themselves as the referrer. A link an assistant writes into its reply without that mark looks like a direct visit, to Lettervisit and to every other analytics tool, so it isn't counted as a citation.

Does it slow my site down?

No. The script loads deferred, after your page, and the middleware records the request without waiting on a response, so nothing sits between a visitor and your HTML.

Does it track my human visitors?

Only if you turn it on. By default Lettervisit counts agents, and the people an AI answer sends you, without keeping anything about any person: no profiles, no advertising cookies. To see which companies and people visit, turn on de-anonymization. The first 10 identified visitors are free; book a call for more.

What can I do with the MCP server?

Ask questions in plain language from Claude, ChatGPT or any MCP client: which pages an agent read, what changed this week, which vendor stopped visiting. The same answers are in the CLI and the API if you'd rather script it.

Why is it free?

Lettervisit is made by The Letter Company, which builds tools for being found and chosen by AI agents. Knowing which agents visit is the first step for everyone, so we don't charge for it.

Meet your other audience.

They're already reading your pricing page. Install Lettervisit in two minutes and find out who they are, what they read, and who sent them. Free.

Get the free script →