macos-font-defaults — set the system fixed-width font

Self-Evolving skill — if a macOS release changes these defaults keys or Stickies' storage, fix this SKILL.md and apply.sh; see the Post-Execution Reflection at the bottom.

macOS has no single system-wide monospaced-font setting. This skill sets the three levers that exist, in one idempotent command:

Resolve the script first — $CLAUDE_PLUGIN_ROOT is NOT a shell variable and expands to empty in a Bash call (it exists only inside plugin manifests and hook/MCP subprocesses):

APPLY="$(cc-plugin-root macos-font-defaults)/skills/macos-font-defaults/apply.sh"

Lever	What it controls
global `NSFixedPitchFont`	`+[NSFont userFixedPitchFontOfSize:]` — TextEdit plain text and other standard-text-system apps
`com.apple.TextEdit NSFixedPitchFont`	TextEdit's plain-text font explicitly (belt-and-suspenders)
Stickies `DefaultFont`	new Stickies notes (archived `NSFont` in the sandbox container plist)

Usage

"$APPLY" check                          # report current values, change nothing
"$APPLY" apply                          # set everything to JetBrains Mono NL (size = macOS default)
"$APPLY" apply --font "Menlo-Regular"   # a different font (PostScript name)
"$APPLY" apply --size 13                # also pin a size (omit to keep macOS default ~11pt)

Always run check first and show the operator the current values before apply.

What it does NOT cover (be honest)

Terminal / iTerm / VS Code / editors keep their own font settings — unchanged.
Apple Notes hardcodes its monospaced face and cannot be redirected to a custom font. Its only mono lever is the per-note Monostyled style (the draft-park skill uses it).
This is not a system-UI font override; menus/Finder are unaffected.

Notes

The default font is the JetBrains Mono NL Nerd Font regular PostScript name JetBrainsMonoNLNF-Regular. apply fails fast if the font isn't installed.
The Stickies step only runs when the stored default differs, and quits a running Stickies first (it would otherwise overwrite the plist on exit). Re-running is safe.
Relaunch target apps to pick up changes; already-running apps cache the font.
Reverse the global lever with defaults delete -g NSFixedPitchFont NSFixedPitchFontSize.

Post-Execution Reflection

After running apply, check before closing:

Did check confirm all three levers? — if a value didn't stick, the key or write path drifted; fix apply.sh.
Did an app fail to pick up the font? — note the relaunch requirement, or add that app's own font key.
Did a macOS update move/rename the Stickies plist or change NSFixedPitchFont semantics? — update the levers table here.

Only update if the issue is real and reproducible — not speculative.