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Open-source MCP tunnels

Let your AI use the tools on your computer. Safely.

Catflap gives Claude, ChatGPT, Cursor and other AI apps a private door to your files, your MCP servers or a sealed sandbox. You decide what is shared, and only you hold the key.

Create a free account Download the app
No open ports or router setup Stop sharing with one click Free and open source
thesis-sandboxSandbox · Python 3.13, R 4.5 · 2 folders Online
https://catflap.uni-obuda.hu/s/anna/thesis-sandbox/mcp
Claude used sandbox_exec 12 seconds ago
Claude ChatGPT Cursor VS Code any MCP client
Two ways in

Start where you are

I just want my AI to help with my files

Install the app, sign in, press Start sharing. The app explains every choice and tells you when your AI is connected. No terminal needed.

Get the desktop app

I run MCP servers and scripts

One command per server, API keys for unattended machines, OAuth (RFC 9728) or per-tunnel bearer tokens for clients.

Terminal 
$ catflap login
$ catflap enter --name weather -- npx -y @mcp/weather
Three steps

From zero to a connected AI in about five minutes

1

Create your account

Your username becomes part of your addresses, like …/s/anna/…. Verify your email and you are in.

2

Share from your computer

Pick what your AI may use: this computer, a sandbox, or any MCP server. Each gets its own address, called a tunnel.

3

Connect your AI

Paste the address into Claude, ChatGPT or Cursor as a custom connector and sign in. The app shows step-by-step help for each.

What you can share

Choose how much your AI can reach

Each option is labelled with what it can touch, before you start.

Contained · recommended

A sandbox

A sealed Podman container with only the tools and folders you pick. Ideal for running code from an AI; the app shows you how to set it up.

Command line: catflap enter --name NAME --sandbox

Depends on the server

An MCP server

Any server that speaks MCP, from npm, PyPI or your own code. It can do what that server can do.

Command line: catflap enter --name NAME -- CMD

Full access

This computer

Read and write files and run commands as you. Powerful, for AI you trust and work you watch.

Command line: catflap enter

Security

Built so the door only opens for you

Only the owner signs in. AI apps connect with your account (OAuth). Nobody else can, unless you give them a token.

No incoming connections. The app connects out; your router and firewall stay closed.

Revocable tokens. Replace a tunnel's token or revoke an API key and old copies stop working at once.

You see every call. The app and the dashboard list what your AI used and when.

Open source

Use this server, or run your own

Catflap is one open-source system: the app, the command line and the server. The app works with any Catflap server; you pick one when you sign in.

This server

catflap.uni-obuda.hu

Nothing to install on a server.

Create a free account
Your own server

Host it yourself

One container beside PostgreSQL and Keycloak. Your users, your data, your domain, under the MIT license.

Terminal 
$ git clone https://codeberg.org/hollorol/catflap.git
$ cd catflap/deploy && cp .env.example .env
# set your domain, passwords and SMTP account in .env, then
$ podman compose --profile tls up -d
Self-hosting guide Source code

Ready when you are.

Free to use. Setup takes about five minutes.

Create a free account Read the guide