Singleton kerning class

Definition

A kerning class has exactly one member. Classes are meant to group glyphs that share kerning behavior — a singleton class is identical to a direct pair and just adds a layer to navigate. Either expand it (e.g. visually-similar glyphs to share the value) or replace it with a direct pair on the spacing tab.

How Patens surfaces this

The Patens audit module checks for kerning-class-singleton across five teaching surfaces: the edit-panel inline issue list, the project-wide audit page, the release pre-flight check, the family hub, and the home-page project tile. Every surface shows the same plain-English explanation and links back to this page. This rule is detection-only — there's no automatic fix because the correction is design-dependent (it requires a judgment call about the glyph's intended shape or the font's intended behaviour). The audit message links to the specific glyph or field that needs attention.

Run this check yourself

Patens runs every audit rule live as you draw — including this one. The editor (in private alpha) shows kerning-class-singleton firing on real glyphs, or check your own work from the CLI:

npx patens audit your-project.font.json

Related rules in Kerning classes

• class-empty Empty kerning class
• class-missing-member Class member missing from project
• class-name-format Kerning class name missing "@" prefix
• kerning-no-classes Many pairs but no classes
• pair-missing-glyph Kerning pair references missing glyph
• pair-orphan-class Kerning pair references undefined class
• sidebearings-no-classes No sidebearing classes