Send a letter from Warp.
Add paperplane to Warp’s MCP settings and it can quote and send a real USPS letter — no account required, free sandbox mode included.
Free to preview — see the exact PDF before you pay. Sending starts at $1.99, no account required.
Set it up in Warp
Step 1
Add via Warp’s MCP settings
{
"paperplane": { "url": "https://sendpaperplane.com/api/mcp" }
}Try it: free, nothing mailed
Tell your agent:
Using the paperplane tools, quote a 1-page certified letter to Property LLC, 1 Main St, Richmond VA 23220, then send it in sandbox mode.Not on Warp? Any surface works.
The same three calls from the CLI, any MCP client or plain REST. Sandbox is free and mails nothing.
{
"paperplane": { "url": "https://sendpaperplane.com/api/mcp" }
}Common questions
Does Warp need a special transport setting?
No — Warp supports both streamable HTTP and SSE, so the plain URL above works without any extra type field.
What tools does Warp get?
quote_letter, send_letter, and get_letter_status for mailing, plus buy_credits for pre-funding sends. Postcards are live (from $1.99) via the REST API’s format field, though not yet an MCP tool argument.
How much does sending cost?
Letters start at $1.99 for First-Class; Certified Mail starts at $12.99. Sandbox mode is free.