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testland/pdf-snapshot-tester

Test PDF outputs by converting per-page to images (`pdftocairo` / pdf2image / Poppler) and running pixel-diff (pixelmatch / Resemble.js / Pillow `ImageChops`) against approved baselines. Per-page-range targeting, threshold tuning, font-substitution warnings, byte-stable PDF metadata stripping (CreationDate, /ID). Use when a product generates invoices, contracts, or regulatory filings whose layout must not shift, and a PDF template, font pack, or generation library is about to change.

79

Quality

99%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

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SecuritybySnyk

Medium

Suggest reviewing before use

Overview
Quality
Evals
Security
Files

Quality

Content

100%

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

A well-structured, executable skill body: tight code, an explicit validation checkpoint and error-recovery feedback loop, and a real one-level-deep reference that keeps the overview lean. It meets the score-3 anchor on all four dimensions.

DimensionReasoningScore

Conciseness

The body assumes Claude's competence — it does not teach what a PDF is or how libraries work — and every section earns its place; the opening two-sentence rationale ('PDFs are binary documents ... Direct binary diff is useless') is skill-specific framing rather than generic padding. Minor duplication between the 'How to use' summary and the expanded Step 1–6 sections is the only tightening opportunity, but it serves navigation rather than verbosity.

3 / 3

Actionability

Every step ships fully executable code or commands — real `pdf2image`/`Pillow` imports, concrete `pdftocairo -png -r 150` invocations, exact thresholds (~0.005), and a copy-paste-ready `test_invoice_pdf_matches_baseline` test — with no pseudocode gaps.

3 / 3

Workflow Clarity

The six-step sequence is clearly ordered with an explicit validation checkpoint (assert diff ratio < threshold), a real feedback loop in the worked example (diff fails → `pdfinfo -list-embedded-fonts` distinguishes real layout shift from font substitution → fix → re-run → refresh baseline), and an anti-patterns table that functions as a checklist for the batch/destructive baseline-update operation.

3 / 3

Progressive Disclosure

SKILL.md is an overview that pushes metadata-stripping and font-substitution detail into a single one-level-deep, well-signaled reference (linked in both Step 6 and the 'Deterministic rendering' section); the referenced file references/deterministic-rendering.md exists, so navigation resolves cleanly.

3 / 3

Total

12

/

12

Passed

Description

100%

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

A dense, third-person description that pairs concrete capabilities with an explicit 'Use when' trigger and a well-bounded niche, avoiding fluff and over-claims. It hits the score-3 anchor on every dimension.

DimensionReasoningScore

Specificity

Lists multiple concrete actions — 'converting per-page to images', 'pixel-diff ... against approved baselines', 'Per-page-range targeting', 'threshold tuning', 'font-substitution warnings', 'PDF metadata stripping (CreationDate, /ID)' — matching the score-3 anchor of several specific concrete actions.

3 / 3

Completeness

Explicitly answers both 'what' (test PDF outputs by rendering pages to images and pixel-diffing against baselines) and 'when' ('Use when a product generates invoices, contracts, or regulatory filings ... and a PDF template, font pack, or generation library is about to change'), with an explicit 'Use when' trigger clause.

3 / 3

Trigger Term Quality

Beyond the tooling names it covers natural user terms — 'invoices, contracts, or regulatory filings whose layout must not shift', 'PDF template, font pack, or generation library is about to change' — which a user would naturally say when needing this skill; not merely technical jargon.

3 / 3

Distinctiveness Conflict Risk

Occupies a clear niche — PDF output visual-regression via pixel-diff against approved baselines — distinct from text extraction or generation; explicit naming of sister skills (html-to-pdf-regression, print-stylesheet-tests) signals well-bounded triggers unlikely to fire for the wrong skill.

3 / 3

Total

12

/

12

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

Reviewed

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