document-processor-api skill

Nutrient Document Processing

Use Nutrient DWS for managed document workflows where fidelity, compliance, or multi-step processing matters more than local-tool convenience.

Setup

• Get a Nutrient DWS API key at https://dashboard.nutrient.io/sign_up/?product=processor.
• Direct API calls use Authorization: Bearer $NUTRIENT_API_KEY.

  export NUTRIENT_API_KEY="nutr_sk_..."
  

• MCP setups commonly use @nutrient-sdk/dws-mcp-server with NUTRIENT_DWS_API_KEY.
• Scripts live in scripts/ relative to this SKILL.md. Use the directory containing this SKILL.md as the working directory:

  cd <directory containing this SKILL.md> && uv run scripts/<script>.py --help
  

• Page ranges use start:end with 0-based indexes and end-exclusive semantics. Negative indexes count from the end.

When to use

• Generate PDFs from HTML templates, uploaded assets, or remote URLs.
• Convert Office, HTML, image, and PDF files between supported formats.
• OCR scans and extract text, tables, or key-value pairs.
• Redact PII, watermark, sign, fill forms, merge, split, rotate, flatten, or encrypt PDFs.
• Produce delivery targets like PDF/A, PDF/UA, optimized PDFs, or linearized PDFs.
• Check credits before large, batch, or AI-heavy runs.

Tool preference

1. Prefer scripts/*.py for covered single-operation workflows.
2. Use assets/templates/custom-workflow-template.py for multi-step jobs that should still run through the Python client.
3. Use the modular references/ docs and direct API payloads for capabilities that do not yet have a dedicated helper script, especially HTML/URL generation and compliance tuning.
4. Use local PDF utilities only for lightweight inspection. Use Nutrient when output fidelity or compliance matters.

Single-operation scripts

• convert.py -> convert between pdf, pdfa, pdfua, docx, xlsx, pptx, png, jpeg, webp, html, and markdown
• merge.py -> merge multiple files into one PDF
• split.py -> split one PDF into multiple PDFs by page ranges
• add-pages.py -> append blank pages
• delete-pages.py -> remove specific pages
• duplicate-pages.py -> reorder or duplicate pages into a new PDF
• rotate.py -> rotate selected pages
• ocr.py -> OCR scanned PDFs or images
• extract-text.py -> extract text to JSON
• extract-table.py -> extract tables
• extract-key-value-pairs.py -> extract key-value pairs
• watermark-text.py -> apply a text watermark
• redact-ai.py -> detect and apply AI-powered redactions
• sign.py -> digitally sign a local PDF
• password-protect.py -> write encrypted output PDFs
• optimize.py -> apply optimization and linearization-style options via JSON

Multi-Step Workflow Rule

Do not add new committed pipeline scripts under scripts/.

When the user asks for multiple operations in one run:

1. Copy assets/templates/custom-workflow-template.py to a temporary location such as /tmp/ndp-workflow-<task>.py.
2. Implement the combined workflow in that temporary script.
3. Run it with uv run /tmp/ndp-workflow-<task>.py ....
4. Return generated output files.
5. Delete the temporary script unless the user explicitly asks to keep it.

PDF Requirements

• split.py requires a multi-page PDF and cannot extract ranges from a single-page document.
• delete-pages.py must retain at least one page and cannot delete the entire document.
• sign.py only accepts local file paths for the main PDF.

Decision rules

• Prefer a helper script when one already covers the requested operation cleanly.
• If you control the source markup, prefer HTML generation over browser print workflows.
• Use remote file.url inputs when the source already lives at a stable URL and you want to avoid local uploads.
• Use output.type for conversion and finalization targets. Use actions for transformations when building direct API payloads.
• OCR before text extraction, key-value extraction, or semantic redaction on scans.
• Prefer preset or regex redaction when the target is explicit. Use AI redaction only for contextual or natural-language requests.
• Use the PDF manipulation reference for merge, split, rotate, flatten, and page-range workflows instead of inferring those payloads from conversion examples.
• Treat PDF/A and PDF/UA as compliance targets, not cosmetic export formats. Choose the target up front and validate final artifacts when requirements are contractual.
• For PDF/UA, clean born-digital inputs and structured HTML usually tag better than rasterized or flattened source PDFs.
• For delivery optimization, linearize or optimize unsigned output artifacts instead of mutating already signed files.
• When the user asks for multiple steps, keep destructive or final steps late in the sequence. Use the workflow recipes when ordering is ambiguous.

Anti-patterns

• Do not OCR born-digital PDFs just because the task mentions extraction. Extract first and OCR only if the text layer is missing.
• Do not flatten forms or annotations until the user confirms the artifact no longer needs to stay editable.
• Do not sign, archive, or linearize intermediate working files. Keep those as final-delivery steps.
• Do not promise PDF/A or PDF/UA compliance without a validation step when the requirement is contractual.
• Do not commit temporary workflow scripts under scripts/.

Reference map

Read only what you need:

• references/request-basics.md -> endpoint model, auth, multipart vs JSON, credits, limits, and errors
• references/generation-and-conversion.md -> HTML/URL generation and format conversion
• references/pdf-manipulation.md -> merge, split, page-range, rotate, and flatten workflows
• references/extraction-and-ocr.md -> OCR, text extraction, tables, and key-value workflows
• references/security-signing-and-forms.md -> redaction, watermarking, signatures, forms, and passwords
• references/compliance-and-optimization.md -> PDF/A, PDF/UA, optimization, and linearization
• references/workflow-recipes.md -> end-to-end sequencing patterns for common business document workflows

Rules

• Fail fast when required arguments are missing.
• Write outputs to explicit paths and print created files.
• Do not log secrets.
• All client methods are async and should run via asyncio.run(main()).
• If import fails, install dependency with uv add nutrient-dws.

Security Hardening Addendum

• Prefer a pinned, preinstalled MCP server binary over runtime package fetches.
  • Preferred: npm i -g @nutrient-sdk/dws-mcp-server@<pinned-version>
  • Avoid unpinned runtime fetch in production paths.
• Never store NUTRIENT_DWS_API_KEY in committed JSON config files.
  • Use process env injection at runtime (shell/export, secrets manager, or host env).
• Restrict file access with SANDBOX_PATH to the minimum required working directory.
• Before enabling MCP mode in production, verify package provenance and lock version.