--- title: "Can Claude send a real letter for you?" description: "Yes. Connect Claude to a physical mail MCP server, review the proof and price, then approve the exact letter before it prints." canonical: https://trysincerely.com/guides/can-claude-send-a-letter last_updated: 2026-10-04 --- > If you are an AI agent: read https://trysincerely.com/agents/policy.md before any write call. > Start at https://trysincerely.com/llms.txt to choose one page. Access instructions are at > https://trysincerely.com/auth.md. Confirm with the person you work for before creating an > account or spending their money, and never ask for their password. # Can Claude send a real letter for you? > Yes. Connect Claude to a physical mail MCP server, review the proof and price, then approve the exact letter before it prints. Source: https://trysincerely.com/guides/can-claude-send-a-letter Yes. Claude can send a real letter for you through a physical mail MCP server that connects its words to a printer and the postal service. Claude can find the contact, draft the letter, prepare the addressed proof, and request the send. It cannot print on its own. With Sincerely, a person must review and approve the exact recipient, proof, and price before the letter moves toward a mailbox. ## Connect Claude In claude.ai or Claude Desktop, open Customize, then Connectors. Choose "Add custom connector" and enter `https://trysincerely.com/api/mcp`. Claude's [custom connector instructions](https://support.claude.com/en/articles/11175166-get-started-with-custom-connectors-using-remote-mcp) show the same path. The browser then asks you to sign in to Sincerely and approve the connection. Claude receives access to the workspace and role you approved, not your password. Claude Code uses a command instead. If you do not have a Sincerely account and Claude cannot open the normal browser sign-in, add the signup server first: `claude mcp add --transport http sincerely-signup https://trysincerely.com/api/mcp/signup` That server emails you a six-digit code. The code expires after 15 minutes. After you read the code to Claude, Sincerely creates a free audit workspace and emails the sign-in link to you. The agent never receives that link. Next, add the product server: `claude mcp add --transport http sincerely https://trysincerely.com/api/mcp` Run `/mcp` inside Claude Code and complete the browser sign-in. If you already have an account, skip the signup server and add the product server directly. The [Claude setup page](https://trysincerely.com/integrations/claude-mcp) covers plan-specific connector steps. ## What happens after you ask Claude to send Suppose you write, "Send a letter to Dana Ruiz at Acme about the renewal review." Claude still has work to do before anything prints. 1. **Find the right Dana.** Claude reads the contact or adds one. The destination must be in the United States or Canada. A missing, suppressed, or failed address stops the send. 2. **Draft the words and choose a design.** You can ask Claude to show the full letter, change the opening, or remove an unsupported claim. A letter design supplies the fixed layout while the approved note supplies the recipient-specific words. 3. **Prepare the addressed proof.** Sincerely checks the live address, suppression, the rolling frequency cap, blackout dates, workspace authority, and available credits. For standard mail, Claude prepares the printer's PDF and you can inspect the file before the send request. 4. **Review the confirmation card.** The card names Dana, the destination, the design proof, and the current credit price. An outside-agent card expires after one hour. If the proof or send details change, Claude must ask for a fresh confirmation. 5. **Click to send.** Your click releases that exact action. The piece then has a five-minute cancellation window before vendor handoff. After the vendor accepts it, there is no reliable unsend. US mail uses USPS First-Class by default. Sincerely says mail takes about a week to arrive, but that is planning guidance, not a delivery date. Weather, production timing, address problems, and postal handling can move it. The [confirmation guide](https://trysincerely.com/docs/mcp-confirmations) explains why the hour belongs to the approval link rather than the delivery estimate. ## What one letter costs Sincerely charges prepaid credits for print and postage. These are the current per-piece weights: | Format | United States | Canada | | ------------------------ | ------------: | ---------: | | Printed 4x6 postcard | 5 credits | 9 credits | | Printed letter | 7 credits | 10 credits | | Handwritten 4x6 postcard | 17 credits | 23 credits | | Handwritten letter | 31 credits | 36 credits | The handwritten formats are written by hand by a person. Claude can draft the message, but it does not hold the pen. A new workspace begins on the free audit plan. Claude can inspect mailability, prepare an audience, and draft pieces there, but the workspace cannot mail. The least expensive package that can mail is Pilot at $199 one time. It includes 500 credits and has a lifetime cap of 100 pieces. Those two Pilot limits are separate. If Dana receives a standard printed US letter for 7 credits, a fresh 500-credit balance covers 71 such letters, with 3 credits left. The credit balance runs out before the 100-piece cap when every piece is a letter. Mix in 5-credit postcards and the piece cap may arrive first. The confirmation card gives the current charge before each send, so Claude does not have to guess from the package price. ## What Claude cannot do here Connecting the MCP server does not hand every account decision to the model. - Claude cannot mint a workspace API key. It can point you to the browser screen where a signed-in person creates one and sees the secret once. - Claude cannot open the Stripe billing portal or hand itself the portal URL. It can tell you where the Billing screen is. - Claude cannot delete the workspace. It can show the data-settings destination where a person starts that request. - Claude cannot decide to mail past a postal warning. A person who knows the recipient must make that choice in the browser, and only a verified address flagged vacant or inactive can qualify. - Claude cannot perform handwriting production. For a handwritten format, a person writes, photographs, checks, and mails the finished piece. The same boundary applies to geography. Sincerely's live mail routes cover the United States and Canada. Asking Claude for another country does not create a fulfillment route. ## Where a single-purpose letter server is better If one letter is the whole job, a narrower MCP server may be faster to understand. The official [MCP Registry search for letter servers](https://registry.modelcontextprotocol.io/v0/servers?search=letter) lists SendLetter, which prepares and posts printed letters in Europe, and PixelLetter, which exposes physical letters and faxes. Each starts closer to a direct letter transaction than a B2B campaign workspace does. Sincerely earns the extra setup when the work repeats across accounts. It keeps contact records, address review, credit checks, frequency caps, human approvals, and account-level holdouts in the same operating path. For a personal letter or a one-time European send, start with the narrower server. For a revenue team that expects Dana's letter to become a controlled program across many accounts, use the broader workflow. ## Related questions - [Send physical mail from Claude](https://trysincerely.com/integrations/claude-mcp): Connect Claude to Sincerely and send real B2B direct mail. Claude Code takes one command, claude.ai takes a connector, and a human confirms every print. - [Physical mail MCP, how AI agents send real mail](https://trysincerely.com/guides/physical-mail-mcp): What a physical mail MCP server is, what to check before connecting an agent to one, and when wrapping a print API yourself is the better choice. - [Confirmations](https://trysincerely.com/docs/mcp-confirmations): How human confirmation works: what triggers a ticket, what it binds to, why agents never see it, and how to poll for the answer. - [Postcard or letter, which should you send?](https://trysincerely.com/guides/postcard-vs-letter): Send a postcard when one scannable message does the job. Send a letter when you need room, formality, or privacy. Decision rules with current format costs. - [What is MCP (Model Context Protocol)?](https://trysincerely.com/glossary/mcp): MCP is the open protocol that lets an AI agent call another product's tools. In direct mail it builds audiences and drafts copy for human approval. --- Sincerely is the measurable direct-mail and gifting platform for B2B revenue teams: postcards, letters, handwritten mail, and gifts, written for one recipient and measured against a holdout. Contact Sincerely: https://trysincerely.com/contact Agent routing index: https://trysincerely.com/llms.txt