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Briefflink MCP server

Which MCP servers are Briefflink's own, from the official registry and from asking its own domain, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-21

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Whose server it is
  • Registry namede.briefflink/letterverified in the MCP registry

The registry name sits under briefflink.de. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-21
  • Stateanswerschecked 2026-10-21
  • Tools4
  • Server calls itselfbriefflink
  • Server version1.0.0
  • Protocol version2025-06-18

On 2026-10-21 the server answered initialize and tools/list without a sign-in. First answer in 177 ms.

Should an agent connect itSkip it
  • Its tools do none of the product's use cases we checked: send a PDF letter by post without printing it; schedule a letter to mail on a chosen future date.

Once connected

  • Keep approval on for send_letter: they delete, send or pay without saying so.
  • create_upload_link, send_letter change data without a sign-in: anyone with the address can call them.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 7, the first on 2026-10-21
  • INITE MCP score49 of 100answers 100 · does the job 0 · definitions 100 · context 100 · connects 100 · lowered by the warning signs below
  • What an agent can do with it0 of 2 use cases
  • Answered100% of days7 of 7 daily checks
  • Median first answer721 ms
  • Space in an agent's context≈ 682 tokensthe definitions of all its tools (4), which an agent carries on every turn
  • Tool definitionsA · 100 of 100
  • Typed results0 of 4 toolsdeclared outputSchema: results come typed, read once
  • Every tool passes all six checks.

What an agent can do with it

  • cannot · send a PDF letter by post without printing it
  • not sure · send letters from ChatGPT or Claude directly
  • cannot · schedule a letter to mail on a chosen future date

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

  • Tools that delete, send or pay, marked as not destructive: send_letter
  • Tools that change data, on a server that answers without a sign-in: create_upload_link, send_letter

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers4 tools · read 2026-10-21
  • get_letter_price

    Berechnet den Endpreis eines Briefes (Druck, Kuvert, Porto) aus Seitenzahl, Einschreiben-Wahl und Zielland. Kein Auftrag, keine Kosten.

  • create_upload_link

    Erstellt einen Link (24 h gültig), über den der Nutzer sein PDF selbst hochlädt. Die upload_id danach an send_letter übergeben.

  • send_letter

    Legt einen Briefauftrag an und gibt einen Stripe-Bezahllink zurück. Der Brief wird erst gedruckt und versendet, wenn der Nutzer bezahlt hat. Dokument per upload_id (aus create_upload_link) oder pdf_base64.

  • get_letter_status

    Zeigt, ob ein Auftrag noch auf Zahlung wartet, bezahlt, versendet oder fehlgeschlagen ist.

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "letter": {
      "type": "http",
      "url": "https://briefflink.de/api/mcp.php"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http briefflink https://briefflink.de/api/mcp.php

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://briefflink.de/api/mcp.php as a custom connector in the settings.

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.