What is Computerwelt?

Computerwelt is a C# library that gives a .NET application a shell and a Python interpreter it can hand to untrusted code, most often code written by a language model. Both are managed implementations of the language, running inside your process against a virtual filesystem you supply. Nothing is forked, nothing is executed, and no file on the host is reachable.

It is a ground-up port of two Rust projects, both MIT-licensed:

They fit together the way they do upstream: the shell exposes Python as its python command, so python script.py runs in the same sandbox, against the same virtual filesystem, under the same resource limits as everything around it.

Project on GitHub Bashkit (upstream) Monty (upstream)

A first taste

using Computerwelt.Emulation.Bash;

var bash = Bash.CreateBuilder()
    .WithWorkingDirectory("/home/agent")
    .WithLimits(ExecutionLimits.Strict)
    .Build();

var result = await bash.ExecAsync("echo hello | tr a-z A-Z");

Console.WriteLine(result.Stdout);   // HELLO

using Computerwelt.Emulation.Python;

var python = new PythonRunner().Run("print(sum(x * x for x in range(5)))");

Console.WriteLine(python.Stdout);   // 30

Or both at once, over one filesystem:

using Computerwelt;
using Computerwelt.Emulation.Bash;

var bash = Bash.CreateBuilder().WithPython().Build();

await bash.ExecAsync("""
    echo '17 4 42' > /data.txt
    python -c "print(max(int(x) for x in open('/data.txt').read().split()))"
    """);
// 42

Packages

Each project's root namespace is its package name, so a type's namespace says which package it ships in. Versions are CalVer (yy.M.<build>), computed by the release pipeline.

What "sandboxed" means here

See The sandbox model for what each of those buys you and where the boundary actually sits.

Where it is used

Computerwelt is the sandbox behind Sudo, the admin assistant in Curiosity Workspace. The workspace configuration is mounted as a virtual filesystem and Sudo edits it with ordinary shell and Python commands, with the workspace supplying the mounts, the extra commands and the limits. It is a worked example of every extension point this library has.

Conformance

Both upstreams ship golden corpora, and both transfer to the port unchanged. They are the definition of "correct" rather than a smoke test:

Both conformance suites are ratchet-based: a per-file baseline is recorded and a run fails if any file regresses.

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