Send mail from Claude (MCP)
Claude can quote, send, and track real USPS letters through paperplane’s native MCP endpoint — add one URL to your MCP config and ask Claude to mail the letter; you approve a payment link and USPS does the rest.
Native MCP endpoint — the agent-first surface
Instead of a hand-rolled Lob call
A mail API wants an account, an API key, a funded balance and a PDF you rendered yourself before the first request. The MCP endpoint takes plain text, quotes it, and hands your human a payment link.
How to set it up
- 1Add the MCP server to your client config (Claude Desktop, Claude Code, or any MCP-compatible client) using the snippet below.
- 2Ask Claude to draft and send the letter — it calls quote_letter for the exact price, then send_letter.
- 3Approve the Stripe payment link Claude hands you (or give it a prepaid credit code — then no link is needed).
- 4Ask “what’s the status of my letter?” anytime — get_letter_status tracks screening → printing → mailed → delivered.
MCP config (Claude Desktop / Claude Code)
{
"mcpServers": {
"mail": { "url": "https://sendpaperplane.com/api/mcp" }
}
}Try it in the sandbox (free, nothing mailed)
“Send a test letter to 1 Main St, Richmond VA in sandbox mode and show me the quote.”
Under the hood
MCP isn’t a bridge to the product — it is the product. The endpoint at /api/mcp exposes three tools (quote_letter, send_letter, get_letter_status) over the same engine as the website, plus a free sandbox. Agent payment rails (x402-style) are next, so budgeted agents can skip the human payment-link step.
Supported action fields
Every integration maps into the same fixed set of fields, the ones the REST API and MCP tools take directly.
| Field | What it does |
|---|---|
| mail_class | first_class, certified, certified_return_receipt, or priority |
| text or pdf_url | the letter body as plain text, or a fetchable PDF to print as-is |
| to | recipient name + street/city/state/zip, verified against USPS data |
| from | return address, printed on the envelope and used for undeliverable mail |
| where the receipt and status updates go — no account required |
Or skip the automation tool: ask Claude or ChatGPT
Every integration here sits on the same MCP endpoint agents use directly. Instead of wiring a trigger to an action, ask Claude or ChatGPT to draft and mail the letter. Same three tools (quote_letter, send_letter, get_letter_status), same price, same free sandbox.
Related integrations
Zapier
Make
n8nSend your first letter from Claude & MCP.
Sandbox runs the whole pipeline for free and mails nothing. Live sends start at $1.99, one all-in price.
{
"mcpServers": {
"mail": { "url": "https://sendpaperplane.com/api/mcp" }
}
}Common questions
Can Claude pay for the letter by itself?
Not with a card — a human approves the Stripe payment link, which is the confirmation assistant platforms require. With a prepaid credit code, sending is hands-off.
Which Claude surfaces support this?
Anything that speaks MCP: Claude Desktop, Claude Code, and other MCP-compatible clients. The endpoint uses streamable HTTP, so no local process is needed.
Is it safe to let an assistant send mail?
A human approves every live payment, screening checks every letter before printing, and sandbox mode exists so agents can test end-to-end for free.