a11y-report

The finding model all tools share: four outcome states, severity, WCAG mapping and a stable JSON contract. It evaluates nothing itself.

Status

0.26.0 on crates.io. Used by auditmysite, astro-post-audit and liveaudit — the first package that is really in use everywhere.

Structure

Public surface

Type	Purpose
Outcome	the four states; NotRun is one of them, not a special case of “passed”
Basis	criterion or recommendation: a best-practice finding (Finding::best_practice) is REVIEW with Basis::BestPractice, never a WCAG failure
Severity, WcagLevel	classification of a finding
Finding, Evidence, Location, SourcePosition	a finding and what it is anchored to; Location::end is the exclusive end of a source range, Finding::id() the stable id (selector, else file and start position)
Report, RuleRun, NotRun, Summary	what a run produced, including the rules that did not run
InputNote, InputKind	Report::inputs: the host notes that an input was incomplete (stylesheet unavailable or unresolved, partial document). Rules do not read these notes; with stylesheet_unavailable present, treat the contrast rules as untested
Extra	host-specific additional fields, without breaking the contract
FindingId, RootCauseId, normalize_selector	stable identifier of a finding (rule + element pattern) and of a cause, the same across pages and across runs
CauseConfidence, ImpactArea, EvidenceBasis	how well a shared cause and an impact are supported
CriterionState	state of an assessment criterion; “not detected” is not “not met”

Extensibility decisions

• Report, Finding, RuleRun, Summary, Evidence, Location, InputNote, NotRun (and Meta in a11y-rules) are #[non_exhaustive]: the crate produces them, hosts only read or build them through constructors, so new fields are not breaking.
• Outcome, Severity and WcagLevel stay exhaustive: they are closed vocabularies, and a new member would change what a verdict means, so a match that breaks is the intended signal.
• The host-input types ComputedStyle, Layout, Rect, Color and Backdrop stay exhaustive: hosts fill them completely, and a field added silently would be left at a default instead of being supplied.
• SourcePosition stays exhaustive: line, column and byte offset are the complete position a parser reports, and the producer fills all three.
• Evidence::source stays a free string: the set of sources is open (ax_tree, dom_attribute, computed, meta, http_header, and what hosts add), it is part of the JSON contract, and an enum would need an Other(String) escape that gives no more safety than the string.

Dependencies

Downward: only serde. Upward: a11y-rules, a11y-perception (planned), all hosts.

Limits

The model says nothing about how a finding was found and whether the measurement was suitable. Anyone who supplies no evidence gets a finding without evidence — the model does not enforce it.