PieterPost MCP - Connect your AI agent to postal mail
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PieterPost MCP connects AI agents to postal mail. From ChatGPT, Claude, Codex, Claude Code, or any MCP client, agents can prepare letters and postcards, use Mailbook contacts, upload attachments or postcard images, create checkout links, and track orders. It brings PieterPost online mail, API, and payment-link workflows into agent tools.
Replies
Pieter Post
Physical mail as an MCP tool is a fun edge because it's one of the few agent actions that's genuinely irreversible once it's in the postbox. What's the confirm boundary here: does a human have to click through the checkout link, or can an agent with a saved payment method quote-and-send in one shot? For a tool that spends money on a physical artifact I'd want the resolved address read back and a hard human gate, since a hallucinated recipient isn't a retry, it's a stranger opening my letter.
Pieter Post
@dipankar_sarkar Exactly. That boundary is the core design. The normal flow is quote, review the final text and resolved address, create a checkout link, then mail after payment. No silent send unless someone has set up a trusted direct-send path with explicit limits. What would you want on the approval screen before it goes physical?
Connecting AI agents to physical mail is a genuinely underexplored
space. The irreversibility angle is the interesting design challenge
here — curious if you're adding a confirmation step before anything
actually ships, since a hallucinated address isn't a retry, it's a
stranger's mailbox.
Would love to see a "draft mode" where agents prepare everything but
a human approves before it goes physical.
Pieter Post
@l_build Yes, draft mode is the default shape we want people to use first. Let the agent prepare the recipient, message, assets, and quote, then a human approves before anything gets paid or mailed. Where would you use that kind of flow first?
Congrats on the launch. I never expected postal mail and AI agents to come together, but this actually makes a lot of sense for businesses that still rely on physical communication.
Pieter Post
@rahul_manjhi1 Thanks Rahul. That is the gap we kept running into: plenty of business workflows still end in physical mail, but the software side usually stops at a PDF or an email. What kind of business mail do you think this fits best?
The Mailbook integration seems really useful. Having contacts ready instead of entering addresses every time could save quite a bit of effort
Pieter Post
@nitesh_kumar98 Totally agree. Mailbook is one of those small things that makes repeat mail much less annoying. Save the address once, send again later without digging it up, and use reminders for things like birthdays or regular cards. What kind of contacts would you keep in there first?
That tiny detail of skipping the stamp-licking step is honestly such a nice touch, love how clean the whole flow feels from envelope to sent.
Pieter Post
@adilewib Thanks Adil. That no-stamp feeling is exactly what we wanted: write it like a normal message, then still get something physical sent properly. Would you use it more for personal notes or business mail?
ModuleX
Letting an agent create a checkout link before anything mails is a clever gate, but I'm curious what the agent actually sees back after it uploads a postcard image. Does it get any confirmation of how the final print looks, or is it flying blind on the physical artifact once payment clears?
Pieter Post
@sezerufukyavuz Great question. The agent can prepare the upload, message, recipient, and checkout. The person still reviews before payment and mailing, so it should not be flying blind. For postcards, we want the preview to show the image, recipient, price, and final send step clearly. What would you want confirmed before trusting it?
How does Pieter Post actually handle the physical delivery part, do you print and mail things on my behalf or is there some kind of kiosk pickup I need to visit nearby?
Pieter Post
@meryemvfjh We print, stamp, and mail it for you. No kiosk and no post office trip needed. You write it online or through the API/MCP flow, review it, pay, and PieterPost handles the physical part. What would you send first?
Tooling Studio
Love it! 😍 How are you thinking about pricing the MCP side? Is it just pay per letter/postcard sent, or will there also be something like a monthly/API plan if people start wiring this into their own tools? Mostly asking because this feels like something I’d try once manually, then immediately want to automate if it works.
Pieter Post
@nick_kramer Yep, MCP is free. You only pay for the letters or postcards you actually send. We wanted it to feel like normal PieterPost: try one, review it, send it, and if it fits your workflow you can keep using it without a separate MCP subscription. What would you automate first?
MCP for postal mail is a pretty novel idea! I can imagine a use-case where you'd want your agent to send out postal advertisements or have it send your friends and family holiday cards or even handle the shipping for small online businesses. I'm curious, is letter/package tracking also included w/ the PieterPost MCP tool? Because that could also be an interesting feature to have.
Pieter Post
@monolithdread Thanks Jordan. Holiday cards are exactly one of those use cases that make this feel useful fast. Tracking depends a bit on the mail type and destination, but when tracking is available we show it and the MCP can check order status too. What would you try first?
@pieterpostcom I'd probably use it for holiday or even automating birthday cards first! haha nice product!