Docs · Metrics

The opt-in Docs family adds seven metrics on top of the always-on Code family. Each one targets a specific way documentation drifts from the source it describes.

For configuration knobs see Docs › Configuration. For the bundled skills see Docs › Skills.

At a glance

Metric	Layer	What it flags	Severity
doc_freshness	A (paired)	source commits since the paired doc last changed	floors (default ≥ 5 High, ≥ 20 Critical)
doc_drift	A (paired)	doc references an identifier no longer in the paired source	uniform Critical
doc_coverage	A (paired)	pair entry whose doc path doesn’t exist on disk	uniform Medium
doc_link_health	A + B	internal relative-path / #anchor link doesn’t resolve	uniform High
orphan_pages	B (standalone)	Layer B doc not linked from anywhere; not paired	uniform Medium
todo_density	A + B	TODO / FIXME / XXX / TBD / [要確認] / [要修正] markers per doc	≥ 3 Medium, ≥ 10 High
doc_hotspot	A (paired)	paired_src_churn × debt composite — flips hotspot=true on docs-family Findings	always Ok (decoration carrier)

Layer A (paired docs) needs a doc ⇔ src mapping in .heal/doc_pairs.json, generated by /heal-doc-pair-setup. Layer B (standalone prose docs) is auto-discovered via the [features.docs.standalone] include / exclude globs.

doc_freshness

“Has the source moved since the doc was last touched?”

Per-pair source-commits-since-paired-doc count. Distance is measured in git commits, not wall-clock days, so the threshold doesn’t shift as the team’s commit pace changes. Floors live in [features.docs.doc_freshness] — defaults: ≥ 1 Medium, ≥ 5 High, ≥ 20 Critical.

doc_drift (Type 1: dangling identifier)

“Does the doc still reference identifiers that exist in the source?”

Scans each Layer A doc, extracts identifier-shaped backtick spans (`Foo::bar`, `processOrder`), and emits a Finding for each one that doesn’t resolve to any identifier in the paired source. Severity: Critical — a reader acting on a missing identifier wastes time looking for code that no longer exists. The fix is mechanical: remove the reference, or restore the identifier under its new name.

Type 2 (signature mismatch) and Type 3 (semantic drift) are deferred to v0.5+.

doc_coverage

“Does the paired doc actually exist on disk?”

Pair entries whose doc path doesn’t exist. Severity: uniform Medium by design — Critical here would incentivise empty-stub manufacturing. Medium says “consider writing this”, not “you must”. The fix is either real content or heal mark accept recording the “won’t doc” decision.

doc_link_health

“Do the internal links in the docs resolve?”

Per-link Findings: MissingPath (relative-path link doesn’t resolve to a file) and MissingAnchor (#anchor doesn’t match any heading in the target). Heading slugs follow the GitHub-style convention (lowercase + non-alnum → -). Severity: High — internal breaks are mechanical to fix and high-impact for readers.

External HTTP links are out of scope — heal is local-only; lychee and similar cover HTTP in CI.

orphan_pages

“Which Layer B docs aren’t reached from anywhere?”

Layer B docs that aren’t linked from any other doc and aren’t paired. Conventional entry points (README.md, index.md at any depth) are seeded as “linked” so they don’t trip the metric. Severity: Medium — an orphan doc isn’t broken, just hard to discover; the fix is usually a one-line link from the parent README.

todo_density

“How many open TODOs is each doc carrying?”

Per-doc count of TODO / FIXME / XXX / TBD / [要確認] / [要修正] markers. Markers inside fenced code blocks (and, by default, backtick-quoted inline code) are excluded so a reference page that describes the marker keywords doesn’t self-flag every paragraph. Severity: ≥ 3 Medium, ≥ 10 High.

Markdown duplication

When [features.docs] is on, the Duplication observer runs a parallel pass over Markdown / RST files. Findings land under the same duplication metric string as the code-side blocks; the distinguisher is the file extension.

The use case is spotting docs copy-pasted across language mirrors (en + ja), across module-specific READMEs, or across API reference pages with shared boilerplate — the fix is usually a “see also” link plus a single canonical source.

Window length is [metrics.duplication].docs_min_tokens (default 100).

Doc Hotspot — which paired doc is most worth updating

Doc Hotspot is the docs-family analogue of code Hotspot. It ranks paired doc ↔ src entries by paired_src_churn × debt, where debt = src_commits_since_doc + weight_drift × dangling_idents. A pair scores high when the source is moving fast and the doc has fallen behind — “of all your docs, this is the next one worth updating”.

Only paired entries from doc_pairs.json are scored. Standalone docs (READMEs, concept guides) live under orphan_pages / todo_density instead.

Doc Hotspot itself always carries Severity::Ok; it decorates the docs-family Findings (doc_freshness, doc_drift, doc_coverage, doc_link_health, todo_density) so the same 🔥 flag points at the next doc-pair worth updating.

Drain pattern

/heal-doc-review frames the findings through the Diátaxis lens — Tutorial / How-to drift first (the highest-leverage fix for confused first-time readers), then Reference, then Explanation. /heal-doc-patch works through the docs slice one commit at a time:

• doc_link_health → fix the relative path or anchor slug.
• doc_drift → remove the stale reference, or restore the identifier under its new name on a clear rename.
• doc_freshness → re-read the paired source and update the doc.
• orphan_pages → add a link from the parent README, or delete the orphan.
• todo_density → resolve the resolvable TODOs; escalate the rest to issues.
• doc_coverage → write a real stub, or heal mark accept if the team decided this source doesn’t need its own doc.

See Docs › Skills for the full contracts.