Your own preset — one file

Adding a theme used to mean editing four places by hand — the builder's palette, the shape, a skin, a preset resource. One command now puts all of them in place.

python3 addons/gohud/tools/new_theme.py neon --from scifi_dark --title "Neon"
python3 addons/gohud/tools/make_theme.py neon      # theme .tres + control artwork
godot --headless --path . --import                  # import the new artwork once
GoUi.use_preset(&"neon")                             # done — it shows up in the picker too

The first line writes themes/palettes/neon.json and themes/presets/neon.tres. The JSON carries every value of the theme it inherits from, fully spelled out, so it doubles as the list of what you can change: delete a key to keep the parent's value, write one to override it. Presets are found by scanning themes/presets/, so no registry code changes — the project setting's dropdown picks it up as well.

What you can change — on one page

Where	What	How
`from`	the parent theme	`dark` · `light` · `scifi_dark` · `medieval_dark` · … or another JSON theme. Omitted keys inherit its values; an inheritance cycle fails
`palette`	background · three surfaces · border · three text tones · accent · four status colours · scrim · shadow · bar track	`"#RRGGBB"`, alpha as `"#RRGGBB@0.35"`
	fill-only vivid colours `*_vivid`	keep bars saturated even when the text colour has to darken — leave one out and the builder says so
	readability	not tuned by hand. Text, borders, the accent and the label on it are pushed by the builder until they clear the thresholds — change only the accent and the checks still pass
`shape`	`kind`	`flat` (rounded) · `cut` (chamfered corners) · `medieval` (forged frames)
	sizes	`radius` · `radius_small` · `radius_large` · `gap` · `gap_small` · `gap_large` · `padding` · `button_height` · `button_padding[4]` — the tokens follow, so panels and widget maths never disagree
	`cut` only	`cut_ratio` · `cut_max` · `corners` (`diagonal`\|`all`) · `glow` · `edge`
	`medieval` only	`material` (0 iron · 1 leather · 2 parchment) · `grain_alpha` · `ornament_scale` · `bevel_strength` · `fonts` — `title`, `subtitle`, `caption`, `body`, `button` mapped to addon-local `res://` font files
`skin`	`base` — the family for the places code draws itself (joystick, slots, badges, coach-mark ring, chips, dividers)	`default` · `scifi` · `medieval`
`skin`	`dials` — the numbers of those places: slot border width and tint, badge padding, chip and alert opacity, joystick ring width and opacity, sci-fi chamfer sizes, glow and bracket	Every parent value is spelled out in the JSON. The builder writes them into `themes/skins/gohud_skin_<id>.tres` — no skin code is touched. Only to change the drawings themselves do you run `--new-skin`, which scaffolds a `GoSkin` subclass
`icons`	the icon set	a `res://` path to a `GoIconSet` resource — kept from a JSON parent when omitted
`dark` · `title`	how the picker shows it	boolean · string

Every dial

The table below is filled by tools/make_site.py straight from the skin scripts' @export lines — add a dial or change a default and the table follows. Use these names under skin.dials in the JSON. A dial whose default reads 14 is an integer, one that reads 10.0 a float — write either form in the JSON and the builder casts to the script's type.

Default skin `GoSkin` — 17

Dial	Default	What it sets
`chip_fill_alpha`	0.16	Fill opacity of a chip's panel.
`chip_edge_alpha`	0.45	Edge opacity of a chip's panel.
`alert_tint`	0.1	How far an alert box's panel is tinted toward its status colour.
`slot_tint_lit`	0.24	Accent tint of a quick-slot panel while its cooldown runs.
`slot_tint_idle`	0.08	Accent tint of a quick-slot panel at rest.
`slot_border_lit`	2	Quick-slot border width (dp) while its cooldown runs.
`slot_border_idle`	1	Quick-slot border width (dp) at rest.
`badge_pad_x`	5	Horizontal inner padding (dp) of a badge (quantity, time left).
`badge_pad_y`	1	Vertical inner padding (dp) of a badge.
`badge_edge_alpha`	0.6	Edge opacity of a badge's panel.
`float_shadow_alpha`	0.45	Shadow opacity of floating cards (coach mark, prompt card).
`float_shadow_size`	14	Shadow blur (dp) of floating cards.
`float_shadow_lift`	4	Downward offset (dp) of a floating card's shadow.
`float_glow_size`	10.0	Glow distance (dp) of a floating panel that glows instead of casting a shadow, like the sci-fi chamfered panel.
`joystick_base_alpha`	0.42	Opacity of the joystick's base disc.
`joystick_ring_alpha`	0.45	Opacity of the joystick's ring.
`joystick_ring_width`	2.0	Width (dp) of the joystick's ring.

Sci-fi skin `GoSkinSciFi` — 10

Dial	Default	What it sets
`cut_chip`	7.0	Chamfer size (dp) of a chip's panel.
`cut_skeleton`	5.0	Chamfer size (dp) of a skeleton panel.
`cut_alert`	8.0	Chamfer size (dp) of an alert box.
`cut_segment`	8.0	Chamfer size (dp) of a segmented control.
`cut_slot`	6.0	Chamfer size (dp) of a quick-slot panel.
`cut_disc_ratio`	0.24	Chamfer of avatars and discs = diameter × this ratio.
`slot_glow_alpha`	0.45	Glow opacity of a slot whose cooldown is running.
`slot_glow_size`	6.0	Glow distance (dp) of a slot whose cooldown is running.
`bracket_arm`	12.0	Arm length (dp) of the coach mark's targeting bracket.
`bracket_thickness`	2.0	Line thickness (dp) of the coach mark's targeting bracket.

Medieval skin `GoSkinMedieval` — 5

Dial	Default	What it sets
`slot_radius`	4.0	Corner radius (dp) of the medieval quick-slot frame.
`leather_grain_alpha`	0.035	Opacity of the subtle leather marks inside quick slots.
`ornament_scale`	1.0	Scale of the metal decorations at quick-slot corners. Menu frames use shape.ornament_scale.
`bevel_strength`	0.18	Strength of the metal highlight along quick-slot edges.
`slot_rivets`	1	Show small metal rivets on quick slots: 0 hides them, 1 shows them.

Subclass the skin (optional)

Only what theme and shape cannot reach — the joystick's hexagon, slot badges, the coach mark's targeting bracket — lives in a skin. Subclass GoSkin, override just those methods, and point the JSON's skin at that resource. A colour-only theme skips this step.

A check keeps the promise. tools/check_scaffold.sh creates a throwaway theme every run — changes the accent, sets the radius to 4 — and verifies generation, token propagation and a clean contrast pass before removing it. The first run found a theme with only its accent changed failing 8 pairs: the builder pushed text colours but used the accent as written. It now pushes the accent and the label on it too.