Building with MCP tools? Proof every job first.

By the USMail.ai team, more than 50 years of combined expertise in printing and mailing

Direct answer: Your integration can create print-to-mail jobs, upload documents and lists, set mail options, request a proof, check address quality and read status with USMail.ai MCP tools. Live tool names come from the server after you sign in with OAuth, and submit approves only within the postage grant a person sets on the account.

These docs are for developers and companies that use USMail.ai MCP as the print-to-mail API in their own products and workflows. You register a USMail.ai account, or several, connect over OAuth, and then use the service like any other customer: your integration creates, uploads and proofs mail jobs and approves them once a person on the account turns on postage grant, and approved jobs are paid from the account's meter balance.

Sign-in: The agent connects over OAuth at https://app.usmail.ai/mcp by signing in to your existing USMail.ai account (Connect / Authorize the usmail server). There is no separate key or token to copy, and you never put a password in a prompt. See auth and billing.

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What can MCP tools do for agents?

This page describes capabilities in plain English, not a schema dump. Names change; the jobs below don't. USMail.ai is an AI print-to-mail platform: You upload. You approve. We produce. The AI suggests setup, such as mail class, paper and color, and a human approves.

Connect. Use the USMail.ai Cursor plugin or the existing usmail server. After connecting, match the skills version to initialize.serverInfo.version.
Create, upload, configure. Create a job, upload documents and lists, and set First-Class, Priority, Certified and print options. A list is recipient data; handle it under your policies. The agent reads the addresses you supply and never suggests one.
Mixed lists. Some rows have a person and a company; some have only a name, and the name is the company. After ingest, read the digested rows.
Proof and status. Generate a proof, list and get jobs, and read the account balance. Priority Mail and Certified Mail include USPS tracking; a regular First-Class letter has no USPS tracking number. The proof is where you review the job, so fix it before you spend. We don't rewrite the document you uploaded.
Cancel draft. Discard a job that hasn't been approved yet, using the tools the server lists or the app.
Postage grant. A human sets postage grant, capped or uncapped. Agents don't run card deposits.

Certified letters cost $1.15 plus the current USPS Certified Mail fee, and USPS tracking is included with every Certified letter. Certified is a mail class you choose before you approve, never an add-on. We don't offer paper Return Receipt yet.

What does submit do?

A human turns on postage grant for the agent, capped or uncapped. With it on, the agent's submit approves a job within that limit, and the money comes from your meter balance. With it off, you review the job and Pay & Approve on the app. We then print, insert, add postage and hand the pieces to USPS.

Until the job is approved, you can change options, replace a file or discard the draft. After approval, an approved job can be unapproved until its mail date. Unapproving puts the money back on your meter, not back on your card. Once the pieces are produced, physical mail can't be unsent. By default, letters you approve before 10 p.m. CT are handed to USPS the next business day. USPS delivery times vary.

What is the sequence?

A human registers and sets up payment in the app.
The agent signs in over OAuth to the usmail server at https://app.usmail.ai/mcp.
The agent creates the job, uploads files and requests a proof.
A human checks the proof.
With postage grant on, submit approves within the limit, then we produce the job.
With postage grant off, a human does Pay & Approve on the app, then we produce the job.

The operator walkthrough is on Getting started, and postage grant details are on the MCP overview.

Where do live tool names come from?

Ask the connected MCP server for its tool list and use those names. Don't copy names from a gist, a screenshot or an old chat. This site doesn't publish a tool catalog or schema. Plain English is the contract here: create job, upload, recipients, proof, address quality, status, cancel draft. We check every address before mailing, and the AI never suggests an address; every address comes from you. USMail.ai is not USPS.

What is not included?

MCP tools don't include an unauthenticated public server, card deposits by agents, a submit that spends postage when no postage grant is set, unofficial install strings or a second connector, or a public tool catalog or schema.

The tools run on the same production path as the app.

Letters starting at $1.15, postage included. For a one-page, single-sided, black-and-white First-Class letter.

There are no contracts, subscriptions or setup fees.

What do people ask about USMail.ai?

What are the MCP tool names?

Don't invent tool names. The live list is on the MCP server after you connect. This page describes capabilities in plain English: create job, upload, recipients, proof, address quality, status, cancel draft.

Does submit print the job?

Not by itself. With postage grant on, submit approves the job within that limit, and then we print, insert, add postage and hand the pieces to USPS. With it off, you review and Pay & Approve on the app.

Can the agent approve production mail?

Only within the postage grant a human sets, capped or uncapped. With it off, you review and Pay & Approve on the app. Agents don't run card deposits.

Can an approved job be stopped?

Yes. An approved job can be unapproved until its mail date. Unapproving puts the money back on your meter, not back on your card. Before approval, you can discard the draft.

Do MCP tools suggest recipient addresses?

No. The agent works with the addresses in the files and lists you supply. The AI never suggests or adds an address.

When does my letter go to USPS?

By default, letters you approve before 10 p.m. CT are handed to USPS the next business day (Monday to Friday). USPS delivery times vary. USPS handles delivery from there. There are no contracts, subscriptions or setup fees.

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