How to send a construction preliminary notice by certified mail, with AI

On a construction job, a missed preliminary notice can cost a subcontractor or supplier their lien rights, and with them their best way to get paid. The notice usually has to go to the owner, the general contractor and sometimes the lender, within a short deadline, and proof of mailing matters.

With Mailsnail connected to your AI assistant, you can prepare the notices and mail each one by certified mail without leaving your desk.

Connect once

Add this URL to Claude, ChatGPT, Cursor or any app that supports MCP connectors, then sign in:

https://api.mailsnail.dev/mcp

Step-by-step instructions for each app are on the setup page.

Prepare it with the assistant

Give it the job details. For example:

I'm a drywall subcontractor. I started work on October 28 at 455 Harbor Way, San Diego CA 92101. The owner is Bayview Holdings LLC, the general contractor is Coastline Builders, and the construction lender is Pacific Trust Bank; their addresses are below. My estimated total is $38,500. Here's a link to the California preliminary notice form I filled in. Mail a copy to each of the three by certified mail with an electronic return receipt. Show me each proof first.

If you don't have a filled-in form, ask the assistant to draft the notice text from your state's required wording, then check it against the statute or your lien service before sending.

What happens next

For each recipient:

1. verify_address checks the address is deliverable. Free.
2. preview_letter renders the notice and returns a proof PDF and the exact price. Nothing is charged.
3. You read the proof. Check the property address, the dates and the amount.
4. send_letter mails it by certified mail and gives you a receipt token.

Pick your proof

Service	What you get	From a balance	One letter by card
Certified	USPS tracking and proof of mailing	$8.61	$8.83
Certified + electronic return receipt	The recipient's signature as a PDF	$11.64	$11.83
Certified + green card	The signed card mailed back to you	$14.27	$14.42

One page, black and white. Extra pages are priced at our cost and the preview always shows the exact figure.

Keep the record

Save every receipt token with the job file. Ask the assistant for the status of each notice and get_letter returns the USPS tracking number, the mailing date and, with an electronic return receipt, the signature PDF. That's the proof a lien claim leans on.

For contractors sending notices on many jobs, the same tools work from Claude Code or Cursor in a script. See preliminary notices via MCP.

What Mailsnail doesn't do

We print and mail exactly what you approve. We don't track lien deadlines for you or give legal advice. Lien law is strict and varies by state, so confirm deadlines and recipients with your state's statute or a construction attorney.

Related guides

• How to send certified mail with a return receipt from an AI agent
• How to send a demand letter by certified mail
• How to send physical mail from an AI agent

claude mcp add -t http mailsnail https://api.mailsnail.dev/mcp

{
  "mcpServers": {
    "mailsnail": {
      "url": "https://api.mailsnail.dev/mcp"
    }
  }
}