Conciseness

The body is table-driven and terse with zero explanation of concepts Claude already knows (no 'what is a PDF' padding). Minor trimmable padding keeps it at anchor 4 rather than 5: the eight near-identical read_document(...) example calls largely restate the supported-formats table, and 'you always call the same tool regardless of format' repeats the earlier 'Always call the tool directly — do not run Python from bash.'

Actionability

Fully executable, copy-paste-ready guidance: concrete calls like read_document(file_path="uploads/paper.pdf", pages="1-10"), the exact JSON return envelope with field meanings, per-format extra keys, the pages-parameter semantics ('only applies to PDF'), the encoding fallback order (utf-8 → utf-8-sig → gbk → gb2312 → big5 → latin-1), and the rapidocr-onnxruntime install remedy — covering all common cases per the level-5 anchor.

Workflow Clarity

Four workflows (paper summary, contract review, spreadsheet quick-look, chart/scanned PDF) each give a clear 2-step sequence, and the OCR workflow includes an explicit error-recovery checkpoint ('If OCR returns empty, tell the user; don't fabricate'). It fits anchor 4 ('clear sequence with most checkpoints present; minor validation gaps') rather than 5 because the other workflows, e.g. contract review's 'Flag key clauses', end with no output-verification step; it stays above anchor 3 since read-only operations carry low risk and one genuine feedback loop exists.

Progressive Disclosure

No bundle files exist (references/, scripts/, assets/ are absent) and none are needed: the body is a well-organized single-level document with clearly headed sections (Purpose, Supported formats, Usage, Return envelope, Workflows, Notes), all content appropriately inline, and no nested or buried references — matching the well-organized-sections ideal for a self-contained tool skill.

Specificity

The description uses concrete verbs ('Read any common document/data file', 'images (OCR)') and exhaustively enumerates formats with extensions (PDF, Word (.docx), Excel (.xlsx/.xls), PowerPoint (.pptx), CSV/TSV, JSON/YAML/TOML, HTML/XML, source-code). It stops short of the level-5 anchor's multiple distinct concrete actions (extract/fill/merge/convert) — the skill performs essentially one action across formats — but is clearly above level 3's 'not comprehensive' coverage.

Completeness

The 'what' is clear and specific (read any common document/data file via the read_document tool, with a full format list), but there is no 'Use when...' clause or equivalent explicit trigger guidance — the judging guideline caps completeness at 3 in that case. This fits the level-3 anchor ('Has a clear what but when is missing or only weakly implied'), not level 4 which requires an explicit, if imperfect, 'when'.

Trigger Term Quality

Natural user vocabulary is comprehensively covered: 'PDF', 'Word (.docx)', 'Excel (.xlsx/.xls)', 'PowerPoint (.pptx)', 'images (OCR)', 'CSV/TSV', 'plain text', 'JSON/YAML/TOML', 'HTML/XML', 'source-code files'. Both synonyms and file extensions appear for nearly every category, matching the level-5 anchor ('comprehensive coverage of natural terms including synonyms and file extensions'); only trivial omissions like '.pdf'/'PDFs' are missing.

Distinctiveness Conflict Risk

The scope 'any common document/data file' is intentionally broad and overlaps with any format-specific skill (a dedicated PDF, Excel, or docx skill would compete for the same triggers). However, the named tool and explicit format list make it more distinguishable than the level-2 anchor ('Helps with document files'), landing on level 3: somewhat specific but still prone to overlap.