How do I install the Cover Creator skill?

Run npx skillmds@latest add cdeistopened/cover-creator in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Cover Creator skill do?

Cover Creator It is listed under Coding & Dev Tools on SkillMD.

Is Cover Creator safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Cover Creator?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Cover Creator free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Cover Creator?

cdeistopened (@cdeistopened) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Cover Creator by cdeistopened — Agent Skill

Name: Cover Creator
Author: cdeistopened

Cover Creator

Generate print-ready KDP paperback covers programmatically. Input: cover art image + book metadata. Output: 300 DPI PDF wrap cover (front + spine + back) ready for KDP upload, plus a Kindle ebook cover.

The skill is the full workflow, not just the script. Art sourcing, design decisions, back cover content research, iterative refinement, and Kindle export are all part of the job.

When to Use

Publishing any book through Amazon KDP
User mentions book covers, KDP covers, cover design
Need to format cover art for Amazon publishing
Building a series with consistent visual branding
Turning public domain art into professional book covers

What It Produces

Print-ready PDF at 300 DPI — full wrap (front + spine + back) with correct KDP dimensions
PNG preview for quick review
Kindle ebook cover — 1600x2560px, cropped from the print front cover
Front cover: title with typographic hierarchy, author name, over gradient-overlaid artwork
Spine: title + author (auto-scaled to fit spine width)
Back cover: description, praise quotes, categories, barcode zone

Requirements

Python 3 with Pillow (pip3 install Pillow)
macOS system fonts: Bodoni 72 (regular, bold, smallcaps), Baskerville (regular, semibold, bold, italic) — all in /System/Library/Fonts/Supplemental/
Cover art image at minimum 300 DPI at cover dimensions

The Pipeline

Step 1: Calculate dimensions (word count → page count → spine width → canvas size)
Step 2: Source cover art (museum databases, public domain verification)
Step 3: Make design decisions (gravity, overlay, typography, colors)
Step 4: Write back cover content (description + real praise quotes)
Step 5: Generate and iterate (run script, study output, adjust, repeat 3-5x)
Step 6: Export Kindle cover (crop front cover to 1600x2560)

Step 1: Calculate Dimensions

Inputs

Word count of the manuscript
Trim size: 5x8, 5.5x8.5, or 6x9 (most common)
Paper color: cream or white

Word Count to Page Count

Trim Size	Words Per Page	Formula
5 x 8	250	`ceil(word_count / 250)`, round up to even
5.5 x 8.5	260	`ceil(word_count / 260)`, round up to even
6 x 9	280	`ceil(word_count / 280)`, round up to even

Always round up to even — KDP requires even page counts.

Spine Width

white paper:          page_count × 0.002252 inches/page
cream paper:          page_count × 0.0025   inches/page
standard color paper: page_count × 0.0032   inches/page
premium color paper:  page_count × 0.002252 inches/page

Full dimension reference with all 14 KDP trim sizes: reference/kdp-dimensions.md

Spine text only allowed if page count > 79.

Full Cover Canvas

canvas_width  = 0.125" bleed + back_trim_w + spine_width + front_trim_w + 0.125" bleed
canvas_height = 0.125" bleed + trim_h + 0.125" bleed

Safety Zones

Trim safety: 0.25" from trim edges on all sides — keep ALL text inside this
Spine safety: 0.0625" on each side of spine (Amazon requirement)

Key Insight: Free Kindle Cover

5x8 trim ratio = 1:1.6 = exact Kindle cover ratio (1600x2560px). The print front cover crops almost perfectly to a Kindle ebook cover. Minor upscale from 1537x2475 to 1600x2560.

Minimum Art Resolution by Trim Size

Trim Size	Front Cover at 300 DPI	Minimum Source
5 x 8	1537 x 2475	~1600 x 2500
5.5 x 8.5	1687 x 2625	~1700 x 2650
6 x 9	1837 x 2775	~1850 x 2800

If the source image is smaller, it will look soft. Find a higher-res version or choose different art.

Step 2: Source Cover Art

Best Sources for Public Domain Art (Ranked by Reliability)

Metropolitan Museum (metmuseum.org) — CC0, excellent quality, API for downloads
- URL pattern: https://images.metmuseum.org/CRDImages/ep/original/FILENAME.jpg
- Use Wikimedia API to find exact filenames: https://commons.wikimedia.org/w/api.php?action=query&titles=File:FILENAME&prop=imageinfo&iiprop=url&format=json
National Gallery of Art (nga.gov) — Open Access
Yale Center for British Art — IIIF, thousands of Turner works
Wikimedia Commons — check license tags (PD-old, PD-Art, CC0)
Google Art Project versions on Wikimedia often have highest resolution (6000+ px)
Rijksmuseum (rijksmuseum.nl) — CC0, Dutch masters
Art Institute of Chicago (artic.edu) — CC0

Public Domain Rules

Condition	Status
Artist died 70+ years ago	Public domain
Published before 1928 (US)	Public domain
Photo of 2D artwork (Bridgeman v. Corel)	No new copyright created
Museum photos from Met, Yale, NGA	Explicitly open access

Search Strategy

Extract 3-5 themes from the book
Match art era to text era when possible
Portraits crop better than landscapes for book covers
For landscape paintings: look for strong vertical energy (sky, clouds, architecture) that survives portrait cropping
Cross-reference Wikimedia for specific artists when museum search is limited
Always crop the frame off museum photos before using as cover art

Rights Checklist

Before using any image:

Artist died 70+ years ago (or work published pre-1928 US)
Not a modern photograph of a 3D sculpture
High-res available (minimum 300 DPI at cover dimensions)
No modern watermarks or overlays
If Wikimedia: license tag says PD-old, PD-Art, or CC0

Step 3: Design Decisions

Art Placement: The `art_gravity` Parameter

Controls which part of a landscape image to keep when cropping to portrait orientation.

0.0 = keep top (sky, clouds, architecture)
0.5 = center (split evenly)
1.0 = keep bottom (foreground, ground, water)

For paintings with dramatic skies, use 0.15-0.25. For paintings with interesting foreground detail, use 0.6-0.8.

Overlay Strategy — The #1 Thing That Separates Good From Bad

NEVER use a flat dark overlay. It kills the painting's tonal range and makes the cover look like a dark rectangle with text.

USE gradient overlays: dark at top (for title readability), dark at bottom (for author name), clear in the middle (let the painting breathe).

Parameter	Range	What It Controls
`overlay_top_alpha`	90-120	Darkness at top edge. Just enough to read white text on clouds.
`overlay_bottom_alpha`	140-170	Darkness at bottom edge. Darker — author name needs contrast against foreground.
`overlay_mid_clear`	0.35-0.50	Vertical position where overlay is most transparent.

The mid-clear zone should align with the painting's most interesting detail. If the painting has a gorgeous sunset at 40% from top, set overlay_mid_clear to 0.40.

The script uses ease-in/ease-out curves for smooth transitions — the gradient is not linear.

Title Typography: Per-Line Scaling

Multi-line titles with per-line scaling create typographic hierarchy. This is what makes a cover look designed rather than typed.

Parameter	What It Does	Example
`title_line_scale`	Scale factor per line (1.0 = base size)	`[0.55, 1.0, 0.45, 1.3]`
`title_leading`	Spacing between title lines	1.2-1.4
`title_size`	Base font size in points at 300 DPI	100-150

The anchor word — usually the distinctive noun — should be the biggest. Articles and prepositions should be smallest.

Example for "THE CRUISE OF THE NONA":

title: "THE CRUISE\nOF THE NONA"
title_line_scale: [0.55, 1.0, 0.45, 1.3]

Result: "THE CRUISE" is medium, "OF THE" is small, "NONA" is largest.

Text Alignment

Center-alignment: safer, works for most compositions
Right-alignment: works when the art has visual weight on the left
Left-alignment: unusual for covers, rarely the right call

Font Pairing

Element	Font	Notes
Title	Bodoni Bold (`bodoni-bold`)	Classic, high contrast serif
Author	Bodoni Small Caps (`bodoni-sc`)	Matches title family
Back cover body	Baskerville (`baskerville`)	Readable, warm
Back cover quotes	Baskerville Bold (`baskerville-bold`)	Stands out from body
Spine title	Baskerville SemiBold (`baskerville-semibold`)
Spine author	Baskerville (`baskerville`)

Max 2 font families total. Bodoni for front cover display, Baskerville for everything else.

Color Palette (Dark/Classical Covers)

These are the proven defaults. Adjust only with reason.

Element	RGB	Description
Title	`(255, 252, 240)`	Warm cream, not pure white
Author	`(255, 252, 240)`	Same warm cream
Spine title	`(220, 200, 160)`	Muted gold
Spine author	`(240, 230, 215)`	Light cream
Background	`(25, 22, 20)`	Near-black brown, not pure black
Spine	`(20, 18, 16)`	Slightly darker than background
Back cover body	`(230, 220, 205)`	Cream
Back cover quotes	`(220, 200, 160)`	Light gold
Praise header	`(210, 190, 145)`	Muted gold
Separator line	`(210, 190, 145)`	Muted gold
Categories	`(150, 145, 135)`	Light gray

Step 4: Back Cover Content

Structure (Top to Bottom)

Opening description — 1-2 paragraphs, what the book is
Highlights/themes paragraph — what the reader gets
"New edition" note — for public domain reprints
Separator line — thin gold rule, inset from margins
"PRAISE FOR [TITLE]" header — regular weight, centered
2-3 attributed quotes — bold, larger than body, research real ones
Categories — bottom left (e.g., "Sailing / Travel Writing / Essays")
Barcode zone — bottom right, white 2"x1.2" rectangle

Researching Real Praise Quotes

For public domain books: find actual praise. Do not fabricate quotes.

Where to look:

Goodreads reviews (sort by most popular)
Publisher pages (Loreto, Ignatius, TAN, Os Justi Press for Catholic books)
Introductions and forewords to modern editions
Contemporary reviews from the original publication era
Literary journals and Catholic publications
Other authors who referenced the work

Format:

quotes: [
    ("\u201cThe quote text here.\u201d", "\u2014 Attribution Name"),
    ("\u201cAnother quote.\u201d", "\u2014 Source, Publication"),
]

Use curly quotes (unicode \u201c and \u201d) and em dash (\u2014) for attribution.

Back Cover Text Sizing (at 300 DPI)

Element	Config Key	Default	Range
Body text	`back_body_size`	38	36-46
Key question	`back_question_size`	40	38-48
Quotes	`back_quote_size`	40	38-48
Attribution	`back_attrib_size`	30	28-36
Praise header	`praise_header_size`	26	24-32
Categories	`category_size`	26	24-32

Mirror Art Effect

The script can paste a faint, horizontally flipped version of the front art onto the back cover. Creates subtle visual continuity.

Parameter	Default	What It Does
`mirror_art_on_back`	`True`	Enable/disable mirrored art on back
`mirror_art_alpha`	`35`	Opacity (0-255). 25-45 range. Higher = more visible art, harder to read text.

Step 5: Generate and Iterate

Running the Script

# Option 1: Edit CONFIG dict in the script, then run
python3 scripts/generate_cover.py

# Option 2: Pass a JSON config file
python3 scripts/generate_cover.py config.json

# Option 3: Override just the art path
python3 scripts/generate_cover.py --art /path/to/painting.jpg
python3 scripts/generate_cover.py /path/to/painting.jpg

Output: cover.png + cover.pdf in the script's directory (or output_dir if set).

The Iteration Loop

This is where covers get good. Plan for 3-5 rounds minimum.

Generate — run the script
Open PNG — study at full resolution AND at thumbnail size
Check these things:
- Title readability at thumbnail (shrink browser to ~120px wide)
- Overlay transparency — is the painting breathing in the middle?
- Spacing balance — title not too close to top, author not too close to bottom
- Spine text legible (script auto-scales, but verify)
- Back cover text not cramped or floating
- Barcode zone clear of text
Adjust config values — see common fixes below
Regenerate — script runs in ~2 seconds

Common Fixes

Problem	Fix
Title hard to read	Increase `overlay_top_alpha` (try 110-130)
Title too small at thumbnail	Increase `title_size` (try 140-160)
Painting looks dead/dark	Reduce `overlay_top_alpha` and `overlay_bottom_alpha` by 20-30
Dead space above title	Decrease `title_zone_top` (try 0.04-0.06)
Dead space below author	Decrease `author_zone_bottom` (try 0.04-0.06)
Overlay hides best part of painting	Move `overlay_mid_clear` to align with that detail
Author name lost in foreground	Increase `overlay_bottom_alpha` (try 160-180)
Spine text invisible	Script auto-scales, but check `spine_title` and `spine_author` strings are set
Back cover text cramped	Reduce `back_body_size` by 2-4pt, or cut a paragraph
Back cover text floating	Increase sizes, or add another praise quote
Art crops badly	Adjust `art_gravity` (lower = more sky, higher = more ground)

Step 6: Export Kindle Cover

Crop the front cover area from the full wrap to 1600x2560px for Kindle.

For 5x8 trim, the front cover is 1537x2475px — nearly exact Kindle ratio. Slight upscale needed.

# Crop front cover from wrap
from PIL import Image
wrap = Image.open("cover.png")
# Front cover starts at: BLEED + BACK_TRIM_W + SPINE_W
# Calculate these from the config
front_left = bleed_px + trim_w_px + spine_px
front_right = front_left + trim_w_px + bleed_px  # include right bleed
kindle = wrap.crop((front_left, 0, front_right, wrap.height))
kindle = kindle.resize((1600, 2560), Image.LANCZOS)
kindle.save("kindle-cover.jpg", quality=95)

Full Config Reference

Every parameter the script accepts, with defaults and valid ranges.

Book Metadata

Key	Type	Default	Description
`title`	string	—	Front cover title. Use `\n` for line breaks.
`subtitle`	string	`""`	Optional subtitle below title.
`author_line_1`	string	—	Primary author line (usually full name).
`author_line_2`	string	`""`	Optional second author line (e.g., "With an Introduction by...").
`spine_title`	string	—	Title for spine (often abbreviated).
`spine_author`	string	—	Author surname for spine.

Dimensions

Key	Type	Default	Description
`trim_w`	float	—	Trim width in inches (5, 5.5, or 6).
`trim_h`	float	—	Trim height in inches (8, 8.5, or 9).
`page_count`	int	—	Total page count (must be even).
`paper`	string	`"cream"`	`"cream"` (0.0025"/page) or `"white"` (0.002252"/page).

Cover Art

Key	Type	Default	Range	Description
`art_path`	string	—	—	Path to cover art image file.
`art_gravity`	float	`0.3`	0.0-1.0	Crop anchor. 0.0=top (sky), 1.0=bottom (ground).
`overlay_top_alpha`	int	`160`	0-255	Darkness at top edge of gradient overlay.
`overlay_bottom_alpha`	int	`120`	0-255	Darkness at bottom edge of gradient overlay.
`overlay_mid_clear`	float	`0.45`	0.0-1.0	Vertical position where overlay is most transparent.
`mirror_art_on_back`	bool	`True`	—	Paste faint mirrored art on back cover.
`mirror_art_alpha`	int	`35`	0-255	Opacity of mirrored back art. 25-45 typical.

Front Cover Layout

Key	Type	Default	Range	Description
`front_align`	string	`"center"`	`"left"`, `"center"`, `"right"`	Text alignment on front cover.
`title_zone_top`	float	`0.08`	0.0-0.3	Fraction of safe area from top where title starts.
`author_zone_bottom`	float	`0.08`	0.0-0.3	Fraction of safe area from bottom where author sits.
`title_line_scale`	list[float]	`[1.0]` per line	—	Scale factor per title line. See typography section.
`title_leading`	float	`1.35`	1.1-1.6	Line spacing multiplier between title lines.

Font Sizes (at 300 DPI)

Key	Default	Range	Element
`title_size`	`130`	90-180	Front cover title (base size before line scaling).
`subtitle_size`	`50`	30-70	Subtitle.
`author_size_1`	`60`	40-80	Primary author name.
`author_size_2`	`40`	28-60	Secondary author line.
`back_body_size`	`38`	32-48	Back cover description paragraphs.
`back_question_size`	`40`	34-50	Back cover key question.
`back_quote_size`	`40`	34-50	Praise quotes.
`back_attrib_size`	`30`	24-38	Quote attributions.
`praise_header_size`	`26`	22-34	"PRAISE FOR..." header.
`category_size`	`26`	22-34	Category line at bottom.

Font Families

Key	Default	Options
`title_font`	`"bodoni-bold"`	`bodoni`, `bodoni-bold`, `bodoni-italic`, `bodoni-sc`, `baskerville`, `baskerville-semibold`, `baskerville-italic`, `baskerville-bold`
`subtitle_font`	`"baskerville-italic"`	Same as above.
`author_font`	`"bodoni-sc"`	Same as above.

Colors (RGB Tuples)

Key	Default	Description
`bg_color`	`(25, 22, 20)`	Canvas background (near-black brown).
`spine_color`	`(20, 18, 16)`	Spine strip color.
`title_color`	`(255, 250, 235)`	Front cover title.
`subtitle_color`	`(240, 230, 210)`	Front cover subtitle.
`author_color`	`(255, 250, 235)`	Front cover author name.
`spine_title_color`	`(220, 200, 160)`	Spine title text (muted gold).
`spine_author_color`	`(240, 230, 215)`	Spine author text.
`back_body_color`	`(230, 220, 205)`	Back cover body text (cream).
`back_question_color`	`(210, 190, 145)`	Back cover key question (gold).
`back_quote_color`	`(220, 200, 160)`	Praise quote text (light gold).
`back_attrib_color`	`(230, 220, 205)`	Quote attribution text.
`praise_header_color`	`(210, 190, 145)`	"PRAISE FOR..." header (gold).
`separator_color`	`(210, 190, 145)`	Separator rule (gold).
`category_color`	`(150, 145, 135)`	Category line (light gray).

Back Cover Content

Key	Type	Description
`back_paragraphs`	list[str]	Opening description paragraphs.
`back_question`	string	Optional bold centered question (empty to skip).
`back_body`	list[str]	Body paragraphs after the question.
`praise_header`	string	e.g., `"PRAISE FOR THE CRUISE OF THE NONA"` (empty to skip).
`quotes`	list[tuple]	`[("Quote text", "— Attribution"), ...]`
`categories`	string	e.g., `"Sailing / Travel Writing / Essays"`

Output

Key	Type	Default	Description
`output_dir`	string	`""`	Output directory. Empty = same as script.
`output_name`	string	`"cover"`	Base filename (produces `{name}.png` + `{name}.pdf`).

Spine Rules

Under 80 pages: No spine text. Script skips spine text automatically.
80-130 pages: Title only, auto-scaled small.
130+ pages: Title + author name.
US convention: Text reads top-to-bottom (script rotates -90 degrees).
Spine safety: 0.0625" padding on each side. The script enforces this.
Spine color: Match the painting's dominant dark tone. Never use light colors — spine shows shelf wear.

Series Branding

When publishing multiple books in a series:

Same script/config template for all covers
Shared color palette (same RGB values)
Consistent layout (title position, font, alignment)
Same spine treatment
Vary only: artwork, title text, subtitle, accent color

The reader should recognize the series from across the room.

Common Mistakes

Flat overlay instead of gradient — the single most common mistake. Kills the painting. Always use gradient.
Pure white text on pure black background — looks harsh. Use warm cream on near-black brown.
Fabricated praise quotes — for public domain books, real quotes exist. Research them.
Ignoring thumbnail readability — the cover must work at 120px wide on Amazon search results.
Too many font families — max 2. Bodoni + Baskerville is the proven pairing.
Skipping iteration — first generation is never the final. Budget 3-5 rounds minimum.
Not cropping museum frames — museum photos often include gilt frames. Crop to the painting.
Wrong genre signal — the art should match the book's era and subject matter.

Integration

Input from: niche-scout (category data), listing-optimizer (title/subtitle), Vellum or word processor (page count)
Output to: KDP upload (PDF for print cover), Kindle upload (JPG for ebook cover)
Art sourcing reference: reference/art-sources.md for museum collections + artist guide
Template verification: Download KDP template from kdp.amazon.com/cover-calculator, overlay on PDF to confirm alignment

Files

cover-creator/
├── SKILL.md                    ← This file
├── scripts/
│   └── generate_cover.py       ← Cover generation script (Pillow)
└── reference/
    ├── art-sources.md          ← Museum collections + artist guide
    └── kdp-dimensions.md       ← Complete KDP dimension formulas, all trim sizes, paper multipliers

Cover Creator

File contents

Cover Creator

When to Use

What It Produces

Requirements

The Pipeline

Step 1: Calculate Dimensions

Inputs

Word Count to Page Count

Spine Width

Full Cover Canvas

Safety Zones

Key Insight: Free Kindle Cover

Minimum Art Resolution by Trim Size

Step 2: Source Cover Art

Best Sources for Public Domain Art (Ranked by Reliability)

Public Domain Rules

Search Strategy

Rights Checklist

Step 3: Design Decisions

Art Placement: The art_gravity Parameter

Overlay Strategy — The #1 Thing That Separates Good From Bad

Title Typography: Per-Line Scaling

Text Alignment

Font Pairing

Color Palette (Dark/Classical Covers)

Step 4: Back Cover Content

Structure (Top to Bottom)

Researching Real Praise Quotes

Back Cover Text Sizing (at 300 DPI)

Mirror Art Effect

Step 5: Generate and Iterate

Running the Script

The Iteration Loop

Common Fixes

Step 6: Export Kindle Cover

Full Config Reference

Book Metadata

Dimensions

Cover Art

Front Cover Layout

Font Sizes (at 300 DPI)

Font Families

Colors (RGB Tuples)

Back Cover Content

Output

Spine Rules

Series Branding

Common Mistakes

Integration

Files

Related skills

Frequently asked questions

How do I install the Cover Creator skill?

What does the Cover Creator skill do?

Is Cover Creator safe to use?

Which AI agents work with Cover Creator?

Is Cover Creator free to use?

Who published Cover Creator?

Art Placement: The `art_gravity` Parameter