PDF

PDF

Summary

Use this skill for PDF reading, extraction, generation, page operations, forms, rendering, and optional OCR. Match the tool to the operation instead of treating PDF as a simple editable text format.

Common neutral backends include pypdf for page and metadata operations, pdfplumber for text and table inspection, ReportLab or pdf-lib for generation, HTML/CSS plus a local browser for typography-heavy documents, Poppler for rendering, and qpdf for structural checks. OCR is a separate, explicitly selected path such as local Tesseract.

When To Use

• Extracting text, tables, metadata, links, bookmarks, or form information
• Splitting, merging, rotating, cropping, stamping, or encrypting documents
• Generating a PDF from structured content
• Rendering pages for visual review
• Running OCR on operator-approved scanned pages
• Comparing page-level content before and after a transformation

Safety Boundaries

• Preserve the original and write transformed output to a new path.
• Treat JavaScript, actions, attachments, forms, links, signatures, and embedded files as untrusted.
• Never execute document JavaScript, launch actions, embedded programs, or external links.
• Do not remove passwords, permissions, signatures, or protection as a way to bypass access controls.
• External OCR or conversion requires explicit approval before upload.
• Warn that any content change can invalidate a digital signature.

If a parser reports corruption, suspicious object expansion, extreme page dimensions, excessive object counts, or unsupported encryption, stop the operation and report the limitation.

Backend Selection

• Use pypdf for page assembly, rotation, cropping, metadata, common forms, and supported encryption operations.
• Use pdfplumber for positioned text and rule-based table extraction.
• Prefer HTML/CSS plus a local browser or WeasyPrint for reports, proposals, manuals, and other prose-heavy documents where typography and page design matter.
• Use ReportLab or pdf-lib for precise drawing, overlays, labels, forms, and documents whose layout is naturally coordinate-driven.
• Use Poppler tools for local text extraction or rendering when installed.
• Use qpdf for structural validation and supported transformations.
• Use Tesseract only for explicitly requested local OCR and retain the original page images.

Do not describe text replacement as general PDF editing. Existing visual content usually requires reconstruction, redaction, annotation, or a source document change rather than in-place prose editing.

Workflow

1. Confirm the requested pages, operation, output path, preservation needs, forms or bookmarks requirements, and whether OCR is allowed.
2. Identify the file type and inspect encryption, signatures, actions, attachments, links, page boxes, fonts, and page count.
3. Decide whether the task is extraction, page transformation, annotation, redaction, generation, or reconstruction.
4. For generation, establish the document type, audience, visual tone, page size, language coverage, font files, hierarchy, color tokens, and recurring components before writing rendering code. Read references/generation.md for the required typography and layout workflow. The reusable assets/chinese-report.css is a neutral starting point for polished Chinese or mixed Chinese/Latin reports, not a substitute for matching the operator's requested brand or style.
5. Select the narrowest local backend that supports the operation.
6. Produce a new output without activating links or embedded content.
7. Reopen the result and check page count, dimensions, metadata, bookmarks, forms, attachments, encryption state, and expected text.
8. Render every changed or generated page to images. Inspect the actual pages, not only the source HTML or drawing commands, and revise visible defects before delivery.
9. For extraction or OCR, sample the output against rendered pages and record ambiguous tables, reading order, missing glyphs, and low-confidence text.

Quality Rules

• Never rely on Helvetica, Times, or another Latin-only base font for Chinese, Japanese, or Korean text. Discover an appropriate local font, verify glyph coverage, and ensure fonts are embedded or otherwise reliably available in the produced PDF.
• Use a deliberate type scale, spacing rhythm, margins, line length, and color palette. A technically valid PDF with backend-default styling is not a finished generated document.
• For prose-heavy documents, prefer semantic flow layout over manually placing every line. Prevent headings, tables, figures, and callouts from splitting in visually confusing ways.
• Check rendered pages for missing-glyph boxes, substituted fonts, clipping, overlap, isolated headings, sparse spill pages, inconsistent spacing, weak contrast, and unreadably dense tables.
• Preserve intended page order, orientation, crop boxes, and dimensions.
• Distinguish visual redaction from secure content removal; verify that redacted text and related objects are not extractable.
• Do not infer table structure without checking coordinates and rendered pages.
• Retain source page references in extracted content when useful.
• Label OCR-derived text and do not silently replace uncertain characters.
• Verify links, bookmarks, forms, and signatures if the requested operation can affect them.

Delivery

Report the output path, page range and operation, tools used, whether OCR or any network service was used, structural and visual checks, signature or form impact, font family and embedding status for generated documents, and extraction or OCR limitations. State explicitly when active content was present but not executed.