3LT Letter Mail — Claude Code MCP server: real letters and faxes
Lets an AI assistant mail physical letters through USPS and send faxes. Useful when a document has to arrive on paper.
claude mcp add --transport http 3lt-letter-mail https://3lgrouptechnology.com/mcpWhat 3LT Letter Mail does
Seven tools come with the server. draft_letter verifies the recipient address, screens the content and returns a quote, mailing nothing. request_send files the send request, and send_status reports where it stands: PENDING, SENT, REJECTED or FAILED. Faxes take more steps — create_fax_draft validates the number, counts pages and quotes, approve_fax clears it, send_fax transmits through Phaxio, get_fax_status tracks delivery.
No tool mails or faxes on its own. Every send carries an approval record: a human tap, or a trusted on_command key auto-sending inside guardrails. Faxes are stricter — approve_fax is required every time, with no zero-prompt path even for trusted keys.
The hosted endpoint is https://3lgrouptechnology.com/mcp over streamable HTTP. Your lms_... key goes in as the api_key argument on each tool call, and the service shows it once. Keys begin at risk level L0 with a $50 monthly cap; reaching the cap stops sends rather than letting them overrun. A letter costs a $1.00 service fee plus postage, a fax the same $1.00 plus roughly $0.07 per page from Phaxio. Running the stack yourself? Without POSTGRID_API_KEY drafts fail at address verification, so nothing goes out.
What it helps with
- mail a USPS letter without leaving the chat
- see the price before anything is sent
- run a bulk mailing with a single standing approval
- deliver a fax to a real fax machine without owning one
- find out where a send request got stuck
Example prompts for the agent
- Draft a letter from
client.pdfand show me the quote - Send that draft and check it with
send_status - Create a fax draft from
invoice.pdfand count the pages
How to install 3LT Letter Mail
Platform CLI: remote server
claude mcp add --transport http 3lt-letter-mail https://3lgrouptechnology.com/mcpPlatform CLI: remote server
codex mcp add 3lt-letter-mail --url https://3lgrouptechnology.com/mcpConfig file
{
"mcpServers": {
"3lt-letter-mail": {
"url": "https://3lgrouptechnology.com/mcp"
}
}
}Config file
{
"servers": {
"3lt-letter-mail": {
"type": "http",
"url": "https://3lgrouptechnology.com/mcp"
}
}
}Platform CLI: remote server
gemini mcp add -t http 3lt-letter-mail https://3lgrouptechnology.com/mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about 3LT Letter Mail
How do I install 3LT Letter Mail in Claude Code?
Run claude mcp add --transport http 3lt-letter-mail https://3lgrouptechnology.com/mcp. Then pass your lms_... key as the api_key argument on every tool call.
What does 3LT Letter Mail do?
It gives an assistant tools to draft, send and track USPS letters and faxes. Nothing goes out directly — each send passes through an approval record.
Can faxes be sent without approval?
No. approve_fax is always required, even for trusted on_command keys.
