Isolated browser Python runs in a Web Worker using WebAssembly, not on your computer’s Python account or Gena’s server. Python sees only its temporary in-memory files; host files, browser credentials, and network APIs are unavailable. Each cell is stopped after 30 seconds; WebAssembly also enforces its memory ceiling. A timeout clears the runtime. Runtime files and variables stay in this tab and are discarded when it is restarted or closed. Notebook source and results may still be autosaved in this browser. Public TuluEng100 examples load into tulu_examples.