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severity-mapping

severity-mapping

github.com/community-accessTesting & quality42977 installsUpdated today
Repository

About severity-mapping

severity-mapping defines shared severity levels for web, document, and Markdown audits. It is intended for accessibility auditors and report authors who need consistent cross-domain scoring and confidence adjustments.

Key features

  1. 01Four canonical severity levels
  2. 02Web, document, and Markdown mappings
  3. 03Per-finding score deductions
  4. 04Page- or file-level score aggregation
  5. 05Web audit confidence modifiers

Use cases

  1. 01Standardize severity across audit domains
  2. 02Calculate page or file scores consistently
  3. 03Deduplicate findings across web scans
  4. 04Adjust web deductions by confidence

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/community-access/accessibility-agents --skill severity-mapping

After installing, type/severity-mappingin Claude Code to confirm it loaded.

Details

From the project README

Severity Mapping

Canonical severity definitions shared across web, document, and markdown audit domains.

Canonical Severity Levels

LevelDefinitionWCAG ConformanceScore Impact
CriticalBlocks access entirely for one or more user groups. No workaround exists.Fails Level A-15 to -22 points
SeriousSeverely impairs access; a workaround may exist but is unreasonable.Fails Level A or AA-5 to -10 points
ModerateCauses friction or confusion; most users can still complete the task.Fails Level AA (advisory)-2 to -4 points
MinorPolish issue; no meaningful barrier for most users.Technique deviation-1 point

Cross-Domain Equivalents

Canonical LevelWeb (axe-core / Playwright)Document (Office/PDF)Markdown
Criticalcritical (axe-core)Missing document title; untagged PDF; missing heading structureBroken anchor link leading to dead navigation
Seriousserious (axe-core)Missing alt text on informational image; table has no headersAmbiguous link text (e.g., "click here"); missing alt text on image
Moderatemoderate (axe-core)Merged table cells; color-only data encodingSkipped heading level; missing table caption
Minorminor (axe-core)Decorative image with non-empty alt; redundant bookmarkEmoji in heading; em-dash used as list separator

Score Impact Rules

Score impacts listed above are additive per finding. When the same issue recurs across many elements:

  • First occurrence — full deduction
  • Same issue type, same page/file — no additional deduction (already counted once per issue rule)
  • Same issue type, different page/file — full deduction applies again to the new page/file score

Conversion Rules (Normalizing Cross-Domain Reports)

When generating a unified report that combines web, document, and markdown findings:

  1. Map each finding to the canonical severity level using the table above.
  2. Apply the score impact from the canonical level, not from the domain-specific tool's internal scoring.
  3. For aggregated scores (portfolio or project level), compute each page/file score independently, then average.
  4. Do not double-count a finding that appears in both an axe-core scan and a Playwright behavioral scan -- deduplicate by rule ID and element location.

Confidence Modifier (Web Domain)

For web audits, confidence level modifies the base deduction:

ConfidenceMultiplierSource Signals
Confirmed1.2xaxe-core + agent code review + Playwright behavioral test
High (two sources)1.0xAny two of the three sources above
High (one source)1.0x (reduced base)Single automated tool, high rule reliability
Medium0.7xSingle source, medium rule reliability
Low0.3xSingle source, low rule reliability or heuristic

Document and markdown audits do not use confidence multipliers -- they use the base score impact only.

Comments

Markdown supported