Kindlepub

KindlePub — Amazon KDP publishing pipeline

Take a finished manuscript all the way onto Amazon. Each format (Kindle ebook, paperback, hardcover) is a SEPARATE KDP title that KDP links on one product page. The Kindle ebook is the fast win; the paperback is the value-priced print edition; the hardcover is the premium edition. You can do one, two, or all three.

Build everything to the edge, then hand the user the irreversible clicks. The user enters credentials, operates native file pickers, sets anything permanent, and presses Publish. You never type passwords or drive an OS file-open dialog.

Cover approach (important): generate the cover ART with Gemini Nano Banana, then assemble the actual cover in KDP Cover Creator — it lays in the title/author typography and auto-sizes the spine to the page count. Do not build a custom print-cover PDF or a custom 6×9 interior PDF; let KDP's tools size and paginate. (This is the path that shipped.)

What you need from the user (gather first)

• The FINAL manuscript source. A Google Doc is ideal; a .docx also works. Confirm it is truly

final — filenames lag content, so open it and read the version stamp (a "v15.7 FINAL" doc beats a "v16 draft" with a higher number).

• Title, subtitle, author name, and the imprint/publisher line.
• Cover art or a cover concept. If they have brand art, great; if not, you will generate it

with Nano Banana (see Phase 3).

• Which formats they want, and their KDP account email.

Flag early: the KDP account needs Two-Step Verification + tax/banking complete before the final Publish and before any royalty payment. That is the user's to finish.

Phase 1 — Lock the source, export a clean DOCX

If the source is a Google Doc, export a clean DOCX through the logged-in browser by navigating to: https://docs.google.com/document/d//export?format=docx. This downloads the .docx with no copy/paste loss. Stage it for the EPUB build and (for print) for upload to KDP.

Phase 2 — Build the Kindle EPUB

Use scripts/build_epub.py. Edit the CONFIG block at the top (input DOCX, title, subtitle, author, contributors, cover JPG path, publisher) and run it. It uses mammoth (DOCX->HTML) + ebooklib, segments chapters, and adds the front matter most manuscripts lack: a copyright page, a medical/crisis disclaimer (the 988 block — keep it for anything touching health or safety), and a navigable table of contents. It preserves in-text diagrams.

Then validate with scripts/validate_epub.py (wraps epubcheck, which needs Java). Ship only on a clean pass. The script already encodes the three ebooklib traps that cost real time the first time:

• Set EpubHtml.content to HTML with NO `` declaration. ebooklib's lxml

path silently returns an EMPTY body on an encoding-declared Unicode string, so your pages come out 0 bytes and "valid."

• Attach CSS with add_link(...), not a `` in your own head — ebooklib rebuilds the

head from the title + links you register.

• After set_cover(create_page=True), set the cover page is_linear=True and pass

write_epub(..., {'epub3_pages': False}), or epubcheck throws OPF-096 / the page-list generator crashes on the empty cover body.

Phase 3 — The cover: Nano Banana art → KDP Cover Creator

Generate the cover art with Nano Banana (Gemini's image model), then assemble the cover in KDP Cover Creator. Cover Creator adds the title/author typography and auto-sizes the spine to the page count, so there is no custom PDF and no manual spine math.

Read references/nanobanana-cover-prompts.md for the prompt recipes and the one rule that matters: AI models always sneak garbled text onto pennants, clothing, book spines, and screens, so the prompt must forbid text on those surfaces — Cover Creator adds the real title later. The flow:

1. Give the user the prompt (and tell them which reference image to attach). They generate the

art in Nano Banana / Gemini and send back the file (no text in the art).

1. In KDP, open Cover Creator, upload that art, and let it lay in the title, subtitle, and

author and size the spine + back automatically. Uncheck "my cover has a barcode" so KDP leaves room for its own. Iterate on the layout with the user.

1. For the Kindle ebook front cover, use Cover Creator's front-cover image (download it) as

the ~1600x2560 JPG you upload in the ebook Content step — same art, one cover everywhere.

(Do NOT build a custom wraparound print-cover PDF — Cover Creator is the path.)

Phase 4 — Print interior (paperback / hardcover) — no custom PDF

Do not build a 6×9 interior PDF. Upload the manuscript DOCX to KDP for the print title; KDP paginates it, and Cover Creator sizes the spine to the resulting page count. Pick Black & white interior for a text book (see the print-cost trap in the walkthrough) and the common 6×9 trim. Let KDP's tools handle pagination and the spine.

Phase 5 — Draft the KDP metadata

Fill in references/metadata-template.md: title, subtitle, author, the back-cover-style description (KDP allows light HTML — paste clean paragraphs via the Description box's "Source" mode), 3 BISAC categories, 7 keywords, the AI-content answers, price, and the release plan. Reuse the description as the online blurb and a trimmed version on the back cover.

Phase 6 — Walk the user through KDP

Drive the browser through Details -> Content -> Pricing -> Publish. Read references/kdp-walkthrough.md for the field-by-field script and every decision (AI-content disclosure, DRM, KDP Select, pre-order dates, the Cover Creator steps, and the print-cost trap that quietly forces a ~$49.99 hardcover). Hand the user every native file picker and the final Publish click.

Phase 7 — Document it

When the book is set up, save a publication record to the user's knowledge base (every KDP book id, the locked blurb + back-cover copy, asset locations, pricing, the AI disclosures, release dates) so the next format and the next book go faster. If the user keeps a notes repo, write it there and commit.

The scripts are templates, not black boxes

The two EPUB scripts each have a CONFIG block at the top — edit it for the book at hand. They are the exact tools that shipped a real title; read them before running so you can adapt rather than fight them. The cover and print spine are done in KDP's own tools (Cover Creator), not in code.

Tools & adapters

| Capability | Claude Code / Cowork | Codex / Cursor / other | |------------|----------------------|------------------------| | Build EPUB | bash + python3 scripts/build_epub.py (pip deps) | same | | Validate EPUB | python3 scripts/validate_epub.py (epubcheck + Java) | same | | Generate cover art | hand user the Nano Banana / Gemini prompt | same | | Assemble cover + spine | KDP Cover Creator in the browser | same | | Drive KDP / native pickers | hand the user the irreversible clicks | same |

Deps: mammoth ebooklib beautifulsoup4 lxml epubcheck (+ Java on PATH for epubcheck).

Portability

Class: portable. A self-contained pipeline with no external coupling and no secrets — the only dependencies are pip packages plus Java for epubcheck, and there is no env config (requires_config: []). The cover and spine are assembled in KDP Cover Creator (no custom PDF), and the worked example in references/nanobanana-cover-prompts.md is fully generic (no real book or author names). The installed original remains the untouched fallback until this copy is validated at parity.

Acceptance check

• Trigger: "put my book on Amazon" / "make this a Kindle book" / "I finished my manuscript, now what".
• Expect: builds an epubcheck-clean EPUB; generates cover art with Nano Banana (no garbled

text); assembles the cover in KDP Cover Creator (auto-spine) and reuses its front for the ebook; uploads the manuscript DOCX for print; drafts KDP metadata; walks Details→Content→Pricing→Publish, handing the user every irreversible click.

• Must NOT: type the user's passwords or drive native OS file pickers; ship an EPUB that fails

epubcheck; build a custom print-cover or 6×9 interior PDF (use Cover Creator

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: jessl2juice
• Source: jessl2juice/kindlepub
• License: MIT
• Homepage: https://jessl2juice.github.io/kindlepub/

Install and usage instructions live in the source repository linked above.