FileSeal Secure Send

io.github.filesealPublished by GitHub account filesealv0.1.3Updated Oct 24, 2026

Send a file to a person as a one-time, encrypted, auto-deleting download link.

VerifiedSTDIODesktop onlyFiles & StorageSecurity & Monitoring

Overview

AI-generated overview

A local MCP server that lets an assistant encrypt files and send them as one-time, expiring FileSeal download links, then check or revoke those sends.

What you can do
Encrypt one or more files client-side and create a share link, either as a key-in-fragment link or as an emailed link to a recipient, with expiry, message and sender name options. Check a send's status, expiry, download count and audit events. Revoke a send so the link stops working and FileSeal attempts to delete the stored files.
When to use it
Useful when you want an assistant to hand a document or image to someone through a self-destructing, encrypted download link rather than an email attachment, and to manage or revoke those links afterwards.
Requirements
Runs locally over stdio, normally launched by an MCP client via npx from the npm package @fileseal/send (Node.js). Requires a FileSeal API key in FILESEAL_API_KEY, created in FileSeal settings; the server exits at startup if it is unset. Optional FILESEAL_API_BASE_URL defaults to the FileSeal service. Network access to FileSeal is needed.
Before you install
The API key is a bearer credential sent on every call; keep it out of shared settings files. Sends are tied to the key, so only sends made with the same key are visible. File names, sender name and message are stored unencrypted and readable by anyone with the link, so keep secrets out of the message. Email mode stores the decryption key server-side. Revoking deletes files and is irreversible. Uploads are capped at 10 files and 3 MB total.

Installation

In SourceWeft

  1. Open FileSeal Secure Send in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

fileseal-send (MCP server)

A standalone Model Context Protocol stdio server that wraps the FileSeal Secure Send API (/v1/sends). It encrypts files client-side (AES-GCM-256) before they ever reach FileSeal and exposes three tools to an MCP client (e.g. Claude).

This package is self-contained: it does not import from the FileSeal Next app. Its crypto (crypto.mjs) mirrors FileSeal's server-side attachment format byte-for-byte (a 12-byte IV followed by AES-GCM ciphertext, with the key base64url-encoded in the link fragment), so that ciphertext it produces decrypts on the FileSeal /receive/[id] page. That page fixes the format: a changed crypto.mjs produces links that will not open.

Tools

  • secure_send: encrypt one or more files and create a send.
    • Inputs: filePath, or filePaths (up to 10 files under one link), or (fileBase64 + filename + mimeType), recipientEmail?, deliveryMode ('link' default | 'email'), expiryHours? (1-168, default 48), message?, senderName?.
    • link mode (default, zero-knowledge for the file): the AES key is never sent to FileSeal; the tool returns the full share link with the key in its #k= fragment.
    • email mode: FileSeal emails the recipient a working link and stores the key server-side. Requires recipientEmail. Pass senderName too: without it the email says the files are from "Someone".
    • Not encrypted, in either mode: the file name, senderName and message. FileSeal stores them as plain text and anyone with the link can read them, so keep secrets out of message.
    • Several files: pass them together as filePaths to send them under one link. Calling once per file makes a separate link for each.
    • Limits: up to 10 files per call, 3 MB in total. The files travel inline as base64 in the request body, which is what caps it; FileSeal's own 10 MB per file is not reachable through this tool. Types: PDF, DOC, DOCX, TXT, JPG, PNG.
  • send_status: { id } → status, expiry, download count, audit events. Only sends created with the same API key are visible.
  • revoke_send: { id } → the link stops working immediately, and FileSeal attempts to delete the encrypted files from its servers.

Environment variables

VariableRequiredDefaultPurpose
FILESEAL_API_KEYyesnoneBearer token sent as Authorization: Bearer <key> on every call. The server exits at startup if unset.
FILESEAL_API_BASE_URLnohttps://fileseal.ukAPI origin. Change it only to point at another FileSeal instance, such as http://localhost:3000 when developing FileSeal itself. Routes are <base>/v1/sends. Versions before 0.1.3 defaulted to http://localhost:3000, so set it explicitly if you pin an older version.

Running

No install needed: npx fetches and runs the latest published version:

bash
FILESEAL_API_KEY=fsk_... \FILESEAL_API_BASE_URL=https://fileseal.uk \npx -y @fileseal/send

The server speaks MCP over stdio, so it's normally launched by an MCP client rather than run by hand.

Run from source
bash
# from this package's directorynpm installFILESEAL_API_KEY=fsk_... \FILESEAL_API_BASE_URL=https://fileseal.uk \node index.mjs

Wiring into Claude (.mcp.json)

json
{  "mcpServers": {    "fileseal-send": {      "command": "npx",      "args": ["-y", "@fileseal/send"],      "env": {        "FILESEAL_API_KEY": "fsk_your_api_key_here",        "FILESEAL_API_BASE_URL": "https://fileseal.uk"      }    }  }}

The "fileseal-send" key is just the local server label; the npm package is @fileseal/send. To run a local checkout instead, point command/args at your copy of index.mjs.

As a Claude Code plugin

The claude-plugin/ folder packages this server as a Claude Code plugin, with a skill that tells Claude how to use it. The plugin asks for your API key when you enable it and keeps it in secure storage rather than in your settings files. To install it from this repository:

text
/plugin marketplace add fileseal/mcp-send/plugin install fileseal@fileseal

It works in Claude Code only. The plugin's README explains why, and lists what it runs and sends.

Source: README.md at commit f5f1dab

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

2
  1. v0.1.3LatestSep 26, 2026
  2. v0.1.1Sep 24, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts