> ## Documentation Index
> Fetch the complete documentation index at: https://mehen.ophi.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Markdown metrics overview

> What mehen reports for Markdown documentation: structural metrics, prose layer, and the AI-era 'filler/lazy structure' family.

mehen treats Markdown as a first-class artifact. Instead of stripping code fences, diagrams, tables,
images, links, and math before counting words, every construct contributes to a dedicated metric suite.

The suite is split into two layers:

* **[Structural layer](#structural-layer)** — language-opaque, AST-driven: LOC family, section tree,
  reading-path complexity, link/table/visual scaffolds, repository grounding, filler/lazy risk, review
  criticality.
* **[Prose layer](/metrics/markdown/prose/overview)** — language-aware (English and Japanese): readability
  ensemble, lexical diversity, wording quality, JTF rules, textlint subset.

<Note>
  Code-style metrics like cyclomatic complexity, NOM, NPA, NPM, and WMC do **not** apply to Markdown —
  prose has no functions, classes, or interfaces to score. mehen emits a Markdown-specific suite tailored
  to prose, code blocks, and references.
</Note>

## Structural layer

| Page                                                                   | Purpose                                                                              |
| ---------------------------------------------------------------------- | ------------------------------------------------------------------------------------ |
| [LOC family](/metrics/markdown/loc-family)                             | Markdown LOC variants by construct: prose / code / tables / math / blank / artifact. |
| [Section tree](/metrics/markdown/section-tree)                         | Heading-derived structure with quality flags.                                        |
| [Effective Content Units](/metrics/markdown/effective-content-units)   | Review-mass normalization across prose and artifacts.                                |
| [MRPC](/metrics/markdown/mrpc)                                         | Reading Path Complexity — cyclomatic-complexity analogue for navigation.             |
| [MCC](/metrics/markdown/mcc)                                           | Cognitive Complexity — local reading burden.                                         |
| [Markdown Halstead](/metrics/markdown/halstead)                        | Markdown-native operators / operands.                                                |
| [DMI](/metrics/markdown/dmi)                                           | Documentation Maintainability Index — composite 0–100.                               |
| [Link Debt](/metrics/markdown/link-debt)                               | Link health and reference burden.                                                    |
| [Table Burden + Scaffold](/metrics/markdown/table-burden)              | Table cost and cognitive scaffolding.                                                |
| [Visual Scaffold](/metrics/markdown/visual-scaffold)                   | Diagrams and images: helping or hurting?                                             |
| [Artifact Debt](/metrics/markdown/artifact-debt)                       | Unlabelled, unparsable, oversized, unexplained artifacts.                            |
| [Repository Grounding](/metrics/markdown/repository-grounding)         | Resolved repo links, paths, identifiers, version facts.                              |
| [Evidence Coverage](/metrics/markdown/evidence-coverage)               | Per-section structural support density.                                              |
| [Filler / Lazy Structure Risk](/metrics/markdown/filler-lazy-risk)     | AI-era flag for "big but vacuous".                                                   |
| [Review Criticality Index](/metrics/markdown/review-criticality-index) | "Should I review this carefully?" score.                                             |
| [Section Balance](/metrics/markdown/section-balance)                   | Are sections sized in a maintainable way?                                            |
| [Good Scaffold](/metrics/markdown/good-scaffold)                       | Bonus credit for helpful technical structure.                                        |

## Prose layer (opt-in, feature-gated)

| Page                                                                               | Purpose                                                             |
| ---------------------------------------------------------------------------------- | ------------------------------------------------------------------- |
| [Overview](/metrics/markdown/prose/overview)                                       | Architectural constraints and tier model.                           |
| [Block-level language detection](/metrics/markdown/prose/language-detection)       | Per-block language tagging.                                         |
| [English readability](/metrics/markdown/prose/english-readability)                 | FKGL, Fog, SMOG, ARI, Coleman-Liau, Dale-Chall, FORCAST, LIX/RIX.   |
| [Lexical diversity](/metrics/markdown/prose/lexical-diversity)                     | MATTR, hapax, density.                                              |
| [Wording quality](/metrics/markdown/prose/wording-quality)                         | Passive, hedges, weasels, wordy, adverbs, nominalizations, cliches. |
| [Inclusive language](/metrics/markdown/prose/inclusive-language)                   | alex / retext-equality flags.                                       |
| [Japanese script composition](/metrics/markdown/prose/japanese-script-composition) | Kanji/hiragana/katakana ratios, registers.                          |
| [Tateishi RS + Jōyō grade](/metrics/markdown/prose/tateishi-and-jouyou)            | Japanese readability scores.                                        |
| [JTF rules](/metrics/markdown/prose/jtf-rules)                                     | Japan Translation Federation 12 rules.                              |
| [textlint-ja subset](/metrics/markdown/prose/textlint-ja)                          | Selected rules from `textlint-rule-preset-ja-technical-writing`.    |

## See also

* [PR comment design](/guides/pr-comment-design) — how Markdown metric deltas surface on pull requests.
* [Concepts → Output formats](/concepts/output-formats) — Markdown vs. JSON shape.