[ethmarks]

This is very interesting. So it's an MCP server that connects to what is effectively a sandboxed MCP "hub". This is a clever middle ground between using dozens of context-munching MCP servers and just giving the agent access to your command line.

One question: why is Deno used? I thought that it was a JavaScript runtime. Can pctx only run sandboxed JavaScript code? If so, what do you do if you need the agent to run a Python script? If not, I don't understand how using a sandboxed JavaScript runtime allows you to sandbox other things.

[ttoinou]

Deno wraps around the V8 engine to brings lots of APIs, features and native TypeScript, here I'm guessing the sandbox feature is using the ability to control what the running code has access to https://docs.deno.com/runtime/fundamentals/security/

[pmkelly4444]

hey! the way it works is that the llm is first given snippets in typescript that tell it how to use the various MCP tools. it then can code, in typescript, and execute all of the tool calls in the deno sandbox. so yes, it can only execute javascript, but this isn't meant to be a full arbitrary code execution env like E2B.dev is, this sandbox is only meant to be a place for MCP calls to happen.

we chose typescript because it's the most token efficient way to pass types and signatures to an LLM, with Python and Pydantic there are extra characters passed around