> ## 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.

# MRPC — Markdown Reading Path Complexity

> Cyclomatic-complexity analogue for a Markdown document's navigation graph.

**MRPC** is the [cyclomatic complexity](/metrics/code/cyclomatic) analogue for a Markdown file. It
builds a document navigation graph `G_doc = (N, E)` where nodes are sections, large code blocks,
diagrams, footnotes, linked repository documents, and external domains, and edges are sequential,
parent-child, internal-link, relative-link, external-link, and artifact-explanation relations.

## Classical form

```text theme={null}
MRPC_raw = |E| − |N| + 2P
```

where `P` is the number of connected components.

## Weighted form

Edges carry weights to reflect different navigation costs:

| Edge type                | Weight |
| ------------------------ | ------ |
| Hierarchy (parent-child) | `0.15` |
| Sequential               | `0.20` |
| Internal anchor          | `0.50` |
| Relative repo link       | `0.80` |
| External                 | `1.00` |
| Broken                   | `1.20` |

```text theme={null}
MRPC = max(1, Σ weight(e) − |N| + 2P)
```

## Interpretation

| MRPC  | Meaning                                                                |
| ----- | ---------------------------------------------------------------------- |
| 1–5   | Mostly linear.                                                         |
| 6–15  | Branchy but contained.                                                 |
| 16–35 | Documentation hub — high navigational complexity.                      |
| > 35  | Documentation subsystem; consider split or profile-specific threshold. |

A tutorial with `MRPC = 20` is suspect; an API index with `MRPC = 20` is normal. Use
profile-specific thresholds rather than a universal cap.

## References

* McCabe, T. J. (1976). *A Complexity Measure.* IEEE Transactions on Software Engineering, SE-2(4):
  308–320 — the cyclomatic ancestor.
  [DOI](https://doi.org/10.1109/TSE.1976.233837) ·
  [PDF](http://www.literateprogramming.com/mccabe.pdf).
* Pirolli, P. & Card, S. (1999). *Information Foraging.* Psychological Review 106(4): 643–675 —
  basis for weighting external vs. relative vs. anchor edges.
  [DOI](https://doi.org/10.1037/0033-295X.106.4.643).

## See also

* [Cyclomatic complexity](/metrics/code/cyclomatic) — the source-code analogue.
* [MCC](/metrics/markdown/mcc) — local cognitive burden.
* [Link Debt](/metrics/markdown/link-debt) — broken/external link cost.