MCP Server for AI Agents — Mail a Physical Letter with send_letter_cz

Postbot is an MCP server. Paste one URL into your AI app and your agent can mail a real letter with the send_letter_cz tool.

① Paste the server URL

Pick your app and copy:

claude mcp add --transport http postbot https://postbot.cz/mcp

Settings → Connectors → Add custom connector
URL: https://postbot.cz/mcp

Settings → MCP → Add new MCP server
URL: https://postbot.cz/mcp (Streamable HTTP)

Settings → Connectors → Advanced → Developer mode
Add connector: https://postbot.cz/mcp

npm i -g @postbotcz/cli
posta send letter.md --to-name "Jan Novák" --to-street "Dlouhá" --to-house "5" --to-city "Praha" --to-zip "110 00"

② Send the first letter

Tell your agent: “Send a registered letter to Jan Novák, Dlouhá 5, 110 00 Praha…” The agent composes the letter and hands you a payment link (registered from 103 CZK, ordinary from 50 CZK). You click, pay by card, the letter mails. No prepaid credit, no subscription.

③ (Optional) Credit for more letters

Sending often? Sign in with Google, top up credit (min 500 CZK), and the agent sends without a card each time. With auto-recharge it never stalls.

What it looks likeyou: send a registered letter to Jan Novák, Dlouhá 5, Praha
agent → send_letter_cz({...})
postbot → 402: rails.oneoff.payUrl (103 CZK)
agent: “Letter's ready — pay here: …”
you: [click, pay by card]
postbot → ✉ dispatched · tracking RR1234567CZ

What the agent can and can't do

Without your click or prepaid credit, the agent can't spend a single koruna.
Every letter has a firm price computed up front from the rendered PDF.
Everything sent is visible on /account — including the tracking number.

llms.txt · mcp.json · openapi.json · auth.md

What /mcp is

/mcp is a hosted MCP server over Streamable HTTP — nothing to install. Add the URL https://postbot.cz/mcp to your agent as a remote connector and it gets the send_letter_cz and get_letter_status tools.

To send from prepaid credit, the agent signs you in via OAuth right inside the conversation — clients like Claude or ChatGPT handle this themselves, using your existing Google account. No API key to copy around.

The first letter needs no sign-in at all: an unauthenticated call returns HTTP 402 with a payment link for that exact letter. You click, pay by card, and the letter mails.

Want to run the server yourself? `bunx @postbot/mcp` starts the stdio version with your own Česká pošta environment variables — same logic, no dependency on the hosted postbot.cz.