Justdrop

ai.justdropPublished by justdrop.aiv0.1.6Updated Oct 24, 2026

Live, end-to-end encrypted, ephemeral file transfer between your AI agent and any device.

VerifiedSTDIODesktop onlyFiles & StorageSecurity & Monitoring

Overview

AI-generated overview

Lets an assistant send and receive files between the local machine and any device through short-lived, end-to-end encrypted rooms.

What you can do
The server exposes four tools: drop sends files or folders and returns a room code, link and QR code; receive creates a room and saves anything dropped into it, decrypted, into a directory; status shows live peer presence and per-file progress; cancel destroys a room the session created or leaves a joined one. Transfers are encrypted before leaving the machine and rooms expire and self-destruct after delivery. No account is needed on either end, and the receiving device only needs a browser.
When to use it
Useful when an assistant needs to hand generated files such as reports or builds to a phone or another device, or pull a file from a phone into the working directory, without setting up shared storage or accounts.
Requirements
Runs locally over stdio via the npm package, requiring Node.js 20 or later. No account or API key is declared. JUSTDROP_ROOT sets the only directory the server may read from or save into; JUSTDROP_DEFAULT_EXPIRY_MINUTES sets default room lifetime. Network access to the JustDrop backend is needed.
Before you install
Anyone with the room code can join, so treat codes as secrets. Files are read from and written to the local disk within JUSTDROP_ROOT, and encrypted content is relayed through a third-party backend. Credential-like files are refused, but review the listed files before sending. Files are encrypted in memory, so large files need matching RAM; the cap is 2GB per file.

Installation

In SourceWeft

  1. Open Justdrop 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

justdrop-mcp

Give your AI agent a way to hand you files — live, end-to-end encrypted, nothing stored.

justdrop-mcp is an MCP (Model Context Protocol) server for JustDrop. Your agent creates a room, you scan a QR or open a link on any device, and the files move — encrypted before they leave the machine, decrypted only on yours, gone when the room closes. No account on either end. The receiving device needs nothing installed: just a browser.

You:    "drop dist/report.pdf to my phone"Agent:  Room code: brave-otter-4821        Link: https://justdrop.ai/app#join=brave-otter-4821        [QR code]You:    *scan, tap, done — the room self-destructs*

It works the other way too: "grab the screenshot from my phone" gives you a QR; whatever you drop from the phone lands decrypted in your working directory, and the agent keeps working with it.

Install

Requires Node.js 20+.

bash
claude mcp add justdrop -- npx -y justdrop-mcp

Or in .mcp.json / any MCP client config:

json
{  "mcpServers": {    "justdrop": {      "command": "npx",      "args": ["-y", "justdrop-mcp"],      "env": {        "JUSTDROP_ROOT": "C:/path/to/allowed/folder"      }    }  }}

Tools

ToolWhat it does
dropSend files/folders. Returns room code + link + QR immediately; the transfer runs automatically when the recipient opens the link. Pass room_code to send into an existing room instead.
receiveReceive files into a directory. Creates a room (code + link + QR) and saves anything dropped into it, decrypted, automatically. Pass room_code to join a room someone else created.
statusLive progress: peer presence, per-file state, saved paths.
cancelDestroys a room this session created (files + metadata deleted), or leaves a joined room.

Configuration

Env varDefaultMeaning
JUSTDROP_BASE_URLhttps://justdrop.aiBackend to talk to (point at http://localhost:3000 for local dev).
JUSTDROP_ROOTserver's working directoryThe only directory the server may read from / save into.
JUSTDROP_DEFAULT_EXPIRY_MINUTES60Room lifetime when a tool doesn't specify one (1–1440).

Safety model

An MCP server that reads local files is a prompt-injection target, so the guardrails are structural, not polite suggestions:

  • Root jail — every path (sent or saved) must resolve inside JUSTDROP_ROOT. Anything else is refused.
  • Credential refusal — dotfiles (.env, .npmrc, …), SSH/TLS keys, keystores, cloud credential files, and shell histories are never sent, even when named explicitly. There is no override flag.
  • Explicit manifests — every drop result lists exactly which files were queued, so the user sees what's leaving.
  • Server-side blocklist parity — extensions JustDrop rejects (.exe, .bat, …) are refused up front with a hint to zip instead.
  • Ephemeral by default — rooms carry an expiry (default 60 min) and self-destruct after delivery.

How the transfer works

  1. drop creates a room and registers an RSA-2048 public key; the tool returns the code/link/QR immediately.
  2. When the recipient opens the link, their browser registers its own key. Rooms are one-to-one by design — treat the room code like the secret it is.
  3. Each file gets a fresh AES-256-GCM key, encrypted for both parties' RSA keys. The encrypted blob is relayed through short-lived signed URLs — the relay never sees plaintext or keys.
  4. Delivery is observed live; the room (and everything in it) is destroyed afterwards.

Files are encrypted in one shot in memory (format parity with the web app), so very large files need commensurate RAM. The hard cap is 2GB per file.

Local development

bash
npm installnpm run verify   # builds, boots ../justdrop-simple dev server, runs both test suites
# or piecewise, against a server you started yourself:npm run buildnode test/e2e.mjs http://localhost:3000        # core roundtrip (both directions + SSE)node test/mcp-smoke.mjs http://localhost:3000  # full MCP stdio protocol exercise

License

MIT

Source: README.md at commit 68d87c3

Tools

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

Version history

1
  1. v0.1.6LatestSep 16, 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