Claude can draft, price and post letters for you. The connection runs over MCP, so it works in the Claude app, in Claude Code and in any other client that speaks MCP.
Let your AI assistant help with the words, ask for a price and review the letter before you decide. Your account, return address and approval stay in your control.
ChatGPT
Officially listed in the ChatGPT catalogue
SendLetter is approved by OpenAI and publicly listed in ChatGPT. Click install, sign in with your SendLetter account and start writing.
Nothing is posted until you approve the exact letter, recipient, return address and final price. A ChatGPT or Claude subscription does not cover printing or postage; that comes from your SendLetter balance. Write on the website
Start with a question, not a dispatch
Show my SendLetter account, balance and return addresses. Do not change anything or send mail.
What does a two-page letter to the Netherlands cost? Quote the price without creating an order.
Draft my text for [recipient and complete postal address]. Show the preview. Do not send yet.
Connecting SendLetter
In ChatGPT: open SendLetter in the catalogue and choose Install. Sign in on the SendLetter screen that opens and confirm the permissions. No developer mode needed.
In Claude: go to Settings → Connectors, choose Add custom connector and paste the server address below. Sign in through OAuth. In Claude Code the same address works with claude mcp add.
3Select SendLetter in your conversation and start with an account check or price request. Always review the document, recipient, return address and final price yourself before approving.
MCP server address for Claude and other clients
https://mcp.sendletter.eu/mcp
Writing “test” in a prompt does not turn a live account into a sandbox. Never send a test letter from a live account.
•Ask for a cancellation letter, have it quote the price, and send it once you agree.
•Have an address checked before anything is printed.
•Ask what happened to a letter you sent last week, without opening the site.
Connecting it
1In Claude, open Settings → Connectors and choose Add custom connector. Once the Claude directory listing is live, SendLetter can be added there in one click.
2Enter https://mcp.sendletter.eu/mcp as the address. In Claude Code: claude mcp add --transport http sendletter https://mcp.sendletter.eu/mcp
3Sign in with your SendLetter account and approve the consent screen.
Sending is a separate step that always needs a quote first, so Claude cannot post a letter in one move. A letter cannot be taken back out of a postbox, and that risk should not sit with an assistant.
From account setup to a reviewed letter
Check your account and return address, start a letter with text or a supported PDF link, review the exact document, then approve sending.
Before connecting
Use your own SendLetter account. Google sign-in and email with password are supported. A ChatGPT or Claude subscription does not include printing or postage.
In ChatGPT, install SendLetter from the public catalogue; it is an approved app, so no developer mode is needed. A custom MCP connection remains possible for workspaces that allow it.
Prepare a complete recipient address and your return address. The account’s saved default sender can be used for new drafts; review it before sending.
A sandbox account simulates delivery without charging or posting. A regular account remains live, even if your prompt says “test”. Check the mode in the returned result.
What you approve
The connection requests six permissions: quote prices, read letters, create drafts, send approved letters, read your account and manage return addresses. Account-write access covers sender addresses and the default sender; it does not grant password changes or account deletion. Sending still needs approval of the exact letter and final price.
Example: prepare and send a letter
1. Check account and sender
Show my connected SendLetter account, balance and saved return addresses. Do not change anything or send mail.
2. Save your sender if needed
I approve saving this return address as Office: [name], [street and number], [postcode], [city], [country]. Make it my default sender.
3. Create a draft
Draft a letter to [recipient and complete postal address]: [your text]. Use my default sender. Show the exact PDF preview and total price. Do not send yet.
4. Review every page
Show the final recipient, return address, page count, postal method, payer, mode and total. I want to inspect the document before deciding.
5. Approve the send, or finish on the website
I have checked the preview. Prepare the final confirmation and show me the exact recipient, sender, payer and total. Only send after I say “I approve”.
6. Follow the same order
Show the status of the letter just sent. Do not create or send another letter.
Replace every bracketed value with your own details. Review the exact document and final price before approving; you can always finish on the website instead. Never assume a live account is safe for testing because a prompt says “test”.
Documents, prices and payment
The draft tool accepts letter text, a PDF attached in the ChatGPT conversation, or a directly accessible HTTPS URL to a finished A4 PDF. Files attached in the conversation can also be enclosed behind the letter: up to 10 PDF, JPEG or PNG files, 50 pages per envelope. The letter itself must be a PDF; a Word file has to be exported to PDF first. A link requiring login or a redirect to a private address cannot be imported. Do not make a confidential document public to work around this: attach it in the conversation or upload it through the website.
A page-count quote is an estimate for the requested configuration. The rendered draft and final preparation determine the actual page count and total. Always inspect the complete preview, recipient, sender and payer.
On a live account, sending normally uses existing balance. An eligible personal letter with insufficient balance may offer checkout for that specific letter on the website. Payment requires your separate action there; the tool does not buy credits or subscriptions.
An organisation balance shortfall must be resolved with its billing administrator. It is not silently charged to your personal account. After website payment, check the existing letter’s status instead of sending it again.
The live SendLetter sign-in screen on the MCP host offers Google and email/password login. This screenshot shows the Dutch interface.A real MCP test connection requests the six permissions, including account information and return-address management. The screenshot uses a dedicated demo account and the Dutch interface.
All 13 available tools
You can use ordinary language. These exact names help when checking a client’s tool scan or configuring your own integration.
Tool
Purpose
get_account_overview
Check account, balance and default sender
list_sender_addresses
List your saved return addresses
save_sender_address
Save an approved return address
set_default_sender
Choose your default sender
validate_address
Validate a postal address
calculate_letter_price
Quote a destination and page count
create_letter_draft
Create a draft from text or a supported PDF link
preview_letter
Review the exact document and price
prepare_letter_send
Recheck recipient, sender, payer and final price
send_letter
Place one order after explicit approval
get_letter_status
Check one letter’s status
list_letters
List your recent letters
cancel_letter
Cancel while production and delivery state still allow it
Connection help
Some functions are missing or account access is refused
Refresh the tool definitions in your custom MCP connection and start a new conversation. Reconnect if prompted and approve account-read and sender-management permissions. For workspace apps, your administrator may also need to enable the actions.
How do I add SendLetter to ChatGPT?
Open SendLetter in the ChatGPT catalogue and choose Install; it is an approved, publicly listed app. Only the custom MCP route needs developer mode in your workspace.
I connected the wrong account
Check the connected account before creating a draft. Revoke that connection from My integrations, reconnect, and choose the correct Google account or email login. Connecting SendLetter does not connect your Gmail mailbox.
The preview or confirmation expired
Ask for a fresh preview and final preparation. Recheck the recipient, document, payer and total, then approve the new confirmation. Do not reuse an expired confirmation.
A request timed out after I approved sending
Check the existing letter first. Your integration must reuse the same sending idempotency key for a retry of the same decision; creating a new draft can create another order.
Can I cancel or undo a letter?
Request cancellation for the existing letter. SendLetter checks whether the server and print provider still allow it. Cancellation after production hand-off is not guaranteed.
Manage or revoke access
Open My integrations in your SendLetter account. Under Connected applications, choose Revoke access for the application you want to disconnect. This removes future access; it does not cancel a letter already submitted. You can connect again and approve the required permissions.
