We've taken a step back from the increasing complexity driven by our early experiments in Outpost Thinking. We set the client aside for a moment and ask if we can hack an existing deno server to run executable helpers as if they were CGI scripts. github 
We took deno's std/http/server.ts and added the simple logic: if a file to be served is executable, execute it and serve the result. Content type will be inferred from the suffix so we discard usual language conventions and rely on the #! interpreter convention to launch the right engine.