Reverse polygons (left-hand to right-hand rule)

I believe https://github.com/mapbox/geojson-rewind will remedy your issue.

The GeoJSON specification is picky about winding order, it helps you generate compliant Polygon and MultiPolygon geometries, and it lets you use Canvas and other drawing libraries's default behavior to color the interior rings of Polygon and MultiPolygon features.

Not a tool, but you can read it with shapely and use shapely.geometry.polygon.orient to orient polygons (the default is already correct). With a few more lines of code you can also orient MultiPolygon by iterating over the included polygons.