| E-RSC005 | Invalid HTML/CSS construct (RSC-005 family) | error | Yes |
| E-NCX | Missing or mismatched NCX / nav document | error | Yes |
| E-TOC | Table of contents points to missing content | error | Yes |
| E-OPF | Missing required metadata (title, language, identifier) | error | Yes |
| E-SPINE | Reading order (spine) is empty or broken | error | Yes |
| E-MIME | Incorrect or missing mimetype / manifest entries | error | Yes |
| E-ENC | Non-UTF-8 encoded content file | error | Yes |
| E-NEST | Severe HTML nesting errors | error | Yes |
| E-LINK | Broken or malformed ebook link | warning | Yes |
| E-CSS | Risky CSS for Kindle layout | warning | Yes |
| E-IMG | Referenced image file is missing | error | No |
| E-FONT | Font file not declared in manifest | warning | Yes |
| C-TRIM | Full wrap size does not match trim + spine + bleed | error | Yes |
| C-SPINE | Spine width differs from page count / paper calculation | error | No |
| C-BLEED | Missing bleed or artwork does not reach bleed edge | error | No |
| C-SAFE | Text or critical art outside the safe zone | warning | No |
| C-BARCODE | Content collides with KDP barcode clear zone | warning | No |
| C-DPI | Raster cover below print-quality DPI | warning | No |
| C-RATIO | Front-only cover uploaded where full wrap is required | error | No |