mailbox.bot

mailbox.bot MCP server

Official hosted Model Context Protocol server for [mailbox.bot](https://mailbox.bot). Production is remote Streamable HTTP at https://mailbox.bot/api/mcp.

Agents send letters, certified mail, postcards, and document packets. mailbox.bot prints, stamps, mails, photographs, tracks, and returns proof. Agent mailboxes are live now: a real street address plus PMB at the staffed, USPS-compliant Manhattan Beach, CA facility, $15/mo. The PMB number is assigned after USPS Form 1583 verification. The online notary fee is waived. Outbound mail uses prepaid credits and has no monthly base fee.

• Website: https://mailbox.bot
• Install: https://mailbox.bot/mcp-install
• Pricing: https://mailbox.bot/pricing
• Public tool catalog: https://mailbox.bot/api/mcp/tools-public
• OpenAPI: https://mailbox.bot/openapi.json and https://mailbox.bot/openapi.yaml
• Registry: bot.mailbox/mailbox (DNS-verified on mailbox.bot)

Connect

Sign in, no key. Clients that support MCP sign-in (claude.ai, ChatGPT, Cursor, Claude Code) can add https://mailbox.bot/api/mcp with no headers. The first tool call opens mailbox.bot's sign-in page, where you choose the agent and Sandbox or Live. On a live connection each letter waits for your approval in the dashboard. Disconnect any time on the API Keys page.

Plugin. This repository is also a Cursor and Claude Code plugin: .cursor-plugin/plugin.json and mcp.json for Cursor, .claude-plugin/ and .mcp.json for Claude Code (/plugin marketplace add arbengine/mailbox-mcp, then /plugin install mailbox-bot@mailbox-bot). Both connect by sign-in and bring the skills/mailbox-bot skill.

With a key. Add the hosted URL to the MCP client and pass a bearer key. Customers do not run a local process.

{

"mcpServers": { "mailbox-bot": { "url": "https://mailbox.bot/api/mcp", "headers": { "Authorization": "Bearer sk_agent_YOUR_KEY_HERE" } } } }

Create an account at mailbox.bot/signup. A live agent key (sk_agent_) sends real mail and spends prepaid credits. A sandbox key (sk_agent_test_) rehearses on the same endpoint with no charge and no physical mail. A member account key (sk_live_) cannot send mail.

Pricing

Published outbound examples start at $2.00 for a 1-page USPS First-Class letter. A dry run returns the exact price for that document, page count, service, and ZIP. That cost_breakdown is the price that applies.

Tools

55 hosted tools. Current tools are listed first. A deprecated tool is still served and names its replacement. Live schemas: public catalog.

get_mailbox

Read the account mailing address: street address plus PMB at the Manhattan Beach, CA facility. The rental is $15/mo and mailboxes are live now. The PMB number is assigned after USPS Form 1583 verification.

get_usage

Read usage events and the prepaid credit balance. Agents can read the balance and cannot buy credits.

list_inbound_forwarding_addresses

List the member's intake aliases on forward.mailbox.bot for scans, photos, and PDFs from an address the operator already controls.

list_inbound_mail

List forwarded inbound mail with compact draft context for a reply.

get_inbound_mail

Read one forwarded inbound item, OCR-backed facts, reply hints, and thread linkage.

list_postal_threads

List physical-mail threads that group inbound context and outbound sends.

get_postal_thread

Read one physical-mail thread and its timeline.

get_mailbox_md

Read this agent's versioned MAILBOX.md instructions before an outbound send.

propose_mailbox_md_edit

Propose an edit to standing instructions. The owner accepts or rejects it.

send_facility_message

Send a message to the facility handling this mailbox.

list_facility_conversations

List conversations with the facility.

get_facility_messages

Read messages in a facility conversation.

update_webhook

Update the legacy agent webhook callback URL and event subscriptions.

send_outbound_mail

Print and mail a document with prepaid credits. Call with dry_run=true and show the price before a live send.

list_outbound_mail

List outbound mail jobs and their status.

get_outbound_mail

Read one outbound job, including cost, status, and fulfillment photos.

cancel_outbound_mail

Cancel queued mail before printing and return eligible prepaid credits once.

create_test_outbound_mail

Create a sandbox outbound record with no charge and no physical mail.

advance_test_outbound_mail

Advance a sandbox outbound record through submitted, ready, mailed, and delivered.

quote_outbound_mail

Price a letter before you have the document: mail class, pages, colour and, for FedEx, the ZIP. Needs no account.

send_text_letter

Mail a letter written as plain text. Goes through send_outbound_mail with the same approval, caps and proof.

estimate_batch_mail

Price a batch of postcards, letters, flyers or pamphlets (10 to 10,000 pieces) before any file exists. Printing and USPS postage included.

create_batch_mail

Create a batch draft from a template link (a PDF, or a PNG/JPG postcard graphic) and recipients inline or by CSV link. Nothing is charged; the exact price comes back with links.proof.

get_batch_mail_proof

A one-hour link to a proof PDF: the template as it prints, then the address label for one recipient at its real size, for the person who checks the batch.

confirm_batch_mail

Pay for a draft from prepaid credits once and queue it for printing. The key's approval and daily-piece policies apply; `max_cost_