The Scale width parameter allows you to change the width of the pattern applied to the path.I have a tikz path that is generated by an external software (Inkscape, svg2tikz export).

You can also choose the pattern for the selected skeleton by pasting it from clipboard (that is, you select and copy to the clipboard the pattern, then select the skeleton, apply the Path along path effect, and paste the pattern). In the effect's control panel in the Path Effects dialog, you can select how many copies of the pattern are attached (either single or repeated) and whether the pattern is stretched to fill the skeleton path. This provides a direct equivalent of 'vector brushes' or 'skeletal strokes' features in other vector editors. With the node edit tool, path A can be changed on-canvas and the result is updated live. The result is that path B is bent along path A.

When this effect is applied to path A (called skeleton), another path B (called pattern) can then be passed as a parameter.

The Pattern along Path effect can curve a path along another path. Inkscape: PatternAlongPath Pattern along path

Inkscape gradient pattern along path