Meowshell

A remote shell you can drop into any .NET app — Android included — in one line, with no server to run, no port to open, and no keys to manage by hand.

Meowshell packages tailscale/tailcat (netcat over Tailscale's data plane, without its control plane) together with meowshell, a companion launcher that fixes up the shell environment tailcat hands a session so it works on Android too, not just desktop. Add the Meowshell package, call one method, and you have a real interactive shell — PTY, tab completion, job control — reachable from anywhere, torn down on your own schedule.

var options = MeowshellOptions.Create(TimeSpan.FromMinutes(5)) with
{
    AuthorizedKeys = "alice@github", // fetches alice's SSH keys from GitHub
};
await using var server = await MeowshellServer.StartAsync(options);
Console.WriteLine(server.Address); // tailcat ssh <address>, from anywhere

AuthorizedKeys is the mode to reach for by default. InsecureNoAuth exists for when the address itself is the only credential you want — pair it with AllowClientKeys so a leaked address alone isn't enough to get a shell.

That one call is the common case, but the same package is a complete C# wrapper around tailcat: an SFTP file service and forced-command sessions alongside the shell, a SOCKS5 proxy, TCP port forwarding, native interactive sessions and file transfer as a client too (no system ssh/scp needed, so this also works from inside an Android app), and one-shot operations for key management, address inspection, and connectivity checks. A persistent MeowshellAgentConnection goes further still: one login multiplexing a shell, the full SFTP verb set, and port forwarding together, and the only one of these that also reaches a general (non-tailcat) SSH host, with real host-key verification and password/certificate/Keystore-backed auth. See dotnet/README.md for the full surface, every option, and the one thing (a console-attached ssh client, as opposed to a programmatic session) an Android app sandbox can't run.

What's in this repo

• Meowshell — the .NET library above (dotnet add package Meowshell): shell/SFTP/forced-command sessions, a SOCKS5 proxy, port forwarding, and one-shot key/address/file operations. See dotnet/README.md for the full API.
• Meowshell.Runtime.{linux,windows,android} — the native tailcat and meowshell binaries for each platform, pulled in automatically as a dependency of Meowshell.
• Meowshell.Demo — a real, installable Android app: one button generates a throwaway shell address.
• Meowshell.AndroidProbe — a minimal app that only proves the packaged binaries are found and run on a real device; what CI checks.
• meowshell, the CLI — a standalone launcher/shim around tailcat, for use outside .NET (Termux, adb shell, scripts).

Supported platforms

Platform	Architectures
Android	arm64-v8a, armeabi-v7a, x86_64, x86
Linux	amd64, arm64, armv7, 386
Windows	amd64, arm64

Building from source

./build.sh                     # every target the toolchain allows
PLATFORMS=linux ./build.sh     # just one

Clones tailscale/tailcat, builds it alongside this repo's meowshell, and writes binaries to dist/. Android needs the NDK (ANDROID_NDK_HOME, r19+) for cgo-based DNS resolution; Linux and Windows are pure Go. See ./verify-binaries.sh and e2e/ for how CI checks the result.

License

MIT for this repo's own code. The vendored/patched tailscale/tailcat source it builds against is upstream's own, BSD-3-Clause-licensed work.