Each language in the repo gets one style sheet of rules, kept in docs/style/. The first is for JavaScript (docs/style/js-mjs.md); Python and C++ are deferred, their stubs untouched until needed.

A style guide earns its place only if it shortens review: one-sentence test per file, one input and one output per stage, dependencies justify themselves in package.json or they do not get added. Tier names are the other half of that: root, mid, slow, leaf (and fast, reserved) say what a module owns without reading it.