A KDP ebook format is not complete merely because every source file made it into an EPUB. A reader must be able to enter through the cover, use the table of contents, read the chapters in order, and reach the colophon at the end. The practical check therefore has two layers: confirm that each resource exists, then confirm that it has the intended role, link target, and reading-order position.
This guide uses a retained synthetic EPUB produced with Rune Studio. It explains what can be checked locally before handoff. It does not claim that the file has passed KDP ingestion or that every reading system will render it identically.
Draw the Book Map Before Export
Create one row for every planned component before opening the export wizard. At minimum, separate the cover, title page, five manuscript chapters, and colophon. For each row, record the source file, whether it belongs in reader navigation, its intended spine position, and the package file that should be generated.
Navigation order and spine order are related, but they are not interchangeable. Navigation is a set of destinations that readers can select. The spine defines the default sequence through the publication. A cover or colophon can belong in the spine without appearing in the chapter list. A compact map can use these fields:
| Component | Source | In chapter navigation | Reading position | Reopen target |
|---|---|---|---|---|
| Cover | cover image | no | first | OPF and cover.xhtml |
| Chapters | five Markdown files | yes | chapter order | nav, NCX, and spine |
| Colophon | approved metadata | no | last | colophon.xhtml |
This map becomes the acceptance reference. Do not infer the intended order from filenames after export; write the intended sequence first.
What the Retained EPUB Actually Proves
The controlled source contains five chapters, one image in each chapter, and a separate cover image. Reopening the retained EPUB produced six packaged image resources and six XHTML image references. Every referenced path resolved inside the package, so the missing-resource count was zero.
The OPF contained nine spine items. The EPUB navigation document and NCX each contained five chapter links. Nine spine items are not an error simply because the manuscript has five chapters: the reading sequence also includes generated components such as the cover, title page, and colophon. A reviewer must resolve each spine ID through the manifest and identify the role of the target file.
Rune’s local inspection returned valid=true. That is evidence about this retained package and this local inspection rule. It is not evidence of KDP acceptance, image-rights clearance, or identical presentation in third-party readers.
Build the Cover, Chapter List, and Colophon in Order
Start from copies of the five chapter files and freeze the mapping between filename and chapter heading. Enter the approved bibliographic values, choose the cover image, and place the five chapters in the order recorded on the book map. Include the chapters in navigation. Keep the colophon after the manuscript and populate it only with information approved for publication.
Export to a new filename. Record the output digest, close the result, and reopen that exact file. Then inspect in this order:
- In the OPF, identify the cover-image property and every packaged image resource.
- In
nav.xhtmlandtoc.ncx, compare all five labels and href targets with the chapter map. - Read the OPF spine from top to bottom and resolve every item reference through the manifest.
- Resolve each XHTML image
srcagainst the packaged resource path. - Open the generated colophon and confirm both its position and its published text.
Keeping the sequence stable matters. If a problem appears at step three, the evidence from steps one and two tells you which layers can remain frozen during repair.
Inspect Destinations, Not Just Totals
A navigation count of five can still conceal a swapped second and third chapter. For every link, record the displayed label, href value, and first heading in the destination XHTML. These three values should describe the same chapter. Apply the same principle to the spine: a list of nine IDs is useful only after each ID is mapped to a real package document.
Image totals require the same discipline. Six files under an image directory do not prove that the XHTML points to them. Begin with each src in the generated XHTML, resolve the relative path, and confirm that the named resource exists. An unreferenced image is not a missing asset, but it should either be removed or documented as intentionally packaged.
This content-level read is what distinguishes a format check from a file inventory. Totals catch omissions; target inspection catches misrouting.
Repair the Sequence Without Rebuilding Valid Assets
A common production mistake is to regenerate every input when only the colophon position is wrong. That creates a large diff and makes the repair difficult to attribute. If all six image resources and all six references already pass, freeze those files and their digests. Change only the chapter-order or colophon control that caused the rejected spine.
Save the corrected EPUB under a new name and retain the rejected package. Compare the two OPF files and verify that only the intended sequence changed. Then rerun navigation, NCX, image-reference, and missing-resource checks. Even a narrow configuration change can alter generated links, so previously valid layers still need regression checks after export.
Do not patch the generated OPF as the normal fix. Return the correction to the authoritative source or export configuration so the next build reproduces it.
Keep Local Structure Separate From Retailer Acceptance
The retained evidence supports these exact observations: nine spine items, five navigation links, five NCX points, six packaged images, six image references, zero missing resources, and a successful local inspection. It does not measure current KDP ingestion, final image dimensions on devices, visual parity across readers, or copyright clearance.
The W3C EPUB 3.3 specification defines standard publication components independently of Rune Studio. Keep standards claims separate from product-operation claims. For Rune Studio, describe only the current Mac workflow and the output that was actually reopened. If KDP validation is required, preserve that platform result with the exact uploaded file as a separate acceptance record.
Complete a Front-to-Back Handoff
Add four result columns to the original map: generated path, observed value, status, and evidence location. The cover row points to its OPF role and cover document. Every chapter row points to its nav, NCX, and spine entries. Every image row connects an XHTML reference to a packaged name. The colophon row records both its final position and the approved public text.
Do not copy the fixed sample’s numeric targets into a different book. A production title with twelve chapters needs a twelve-chapter navigation expectation defined before export. The method remains the same even when the totals change.
Finally, close and reopen the exact handoff EPUB. Move from the cover to chapter one, use the table of contents to open each chapter, continue through the default reading order, and reach the colophon at the end. A reliable KDP ebook format handoff combines that human route check with the package-level evidence; neither one replaces the other.