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html-xml-lang-mismatch

Use when applies to XHTML documents and polyglot HTML documents that must parse correctly as both HTML5 and XML. For modern HTML5-only documents, only `lang` is needed and `xml:lang` is not required. Check when auditing documents served as application/xhtml+xml or documents that include both attributes.

64

Quality

76%

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tessl review fix ./skills/html-xml-lang-mismatch/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

78%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The content is a well-structured, lean overview with concrete audit/fix guidance and an appropriately placed reference file for examples. The chief improvement is adding an explicit post-fix verification step and trimming the mild redundancy across intro/Quick Reference/Explain.

Suggestions

Add an explicit verify-after-fix checkpoint in the Fix section (e.g., 'Re-inspect <html> to confirm both attributes now match and the value is a valid BCP 47 tag').

Consolidate the repeated lang/xml:lang-matching rationale between the intro, Quick Reference, and Explain to reduce redundancy.

Surface at least one inline correct/incorrect markup snippet in the Check section so the core example is visible without opening the reference.

DimensionReasoningScore

Conciseness

The body is sectioned and largely efficient, but the intro, Quick Reference, and Explain sections restate the core lang/xml:lang-matching fact, leaving minor trimmable redundancy.

4 / 5

Actionability

Check and Fix give concrete, specific guidance (inspect <html>, compare subtags, validate BCP 47, remove xml:lang for HTML5); code examples live in the reference file, which is appropriate for this audit skill, leaving only minor gaps inline.

4 / 5

Workflow Clarity

The Check→Fix sequence is clear and unambiguous for this single-purpose skill, but there is no explicit re-verification step after applying a fix, a minor checkpoint gap.

4 / 5

Progressive Disclosure

The body is a concise overview organized into clear sections with a single, well-signaled one-level-deep pointer to references/rule.md (a real file) for code examples and details, making navigation easy.

5 / 5

Total

17

/

20

Passed

Description

73%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

The description targets a well-defined, distinctive niche with explicit trigger guidance and good keyword coverage. Its main weakness is specificity — it states when to apply more concretely than what concrete actions the skill performs.

Suggestions

Lead with the concrete capability (e.g., 'Verifies that lang and xml:lang on <html> are identical valid BCP 47 tags') before the 'Use when' clause.

Add 1-2 more concrete actions such as 'flags mismatches and invalid language tags' to lift specificity.

Consider adding common synonyms like 'language attribute' or file-context cues to round out trigger terms.

DimensionReasoningScore

Specificity

Names the domain clearly (XHTML/polyglot documents, lang/xml:lang) but offers only one concrete action — 'Check when auditing documents' — without enumerating the verification steps, so coverage is not comprehensive.

3 / 5

Completeness

An explicit 'Use when…' trigger is present and specific, and the 'what' ('Check when auditing documents… that include both attributes') is stated, but the action description is slightly implicit rather than a crisp capability statement.

4 / 5

Trigger Term Quality

Includes natural domain terms a user would say ('XHTML documents', 'polyglot HTML documents', 'application/xhtml+xml', 'lang', 'xml:lang') with good coverage, though a few synonyms or extensions are absent.

4 / 5

Distinctiveness Conflict Risk

The niche is narrow and specific (lang/xml:lang mismatch on XHTML/polyglot documents) with distinct triggers, giving minimal overlap risk with other skills.

5 / 5

Total

16

/

20

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

metadata_version

'metadata.version' is missing

Warning

Total

15

/

16

Passed

Repository
thedaviddias/Front-End-Checklist
Reviewed

Table of Contents

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