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PDF Viewer — Interactive Document Workflows

You have access to a local PDF server that renders documents in a live

viewer and lets you annotate, fill forms, and place signatures with

real-time visual feedback.

When to use this skill

Use the PDF viewer when the user wants interactivity:

• "Show me this contract" / "Open this paper"
• "Highlight the key terms and let me review"
• "Help me fill out this form"
• "Sign this on page 3" / "Add my initials to each page"
• "Stamp this CONFIDENTIAL" / "Mark this as approved"
• "Walk me through this document and annotate the important parts"

Do NOT use the viewer for pure ingestion:

• "Summarize this PDF" → use the native Read tool directly
• "What does page 5 say?" → use Read
• "Extract the table from section 3" → use Read

The viewer's value is showing the user the document and collaborating

on markup — not streaming text back to you.

Tools

list_pdfs

List available local PDFs and allowed local directories. No arguments.

display_pdf

Open a PDF in the interactive viewer. Call once per document.

• url — local file path or HTTPS URL
• page — initial page (optional, default 1)
• elicit_form_inputs — if true, prompts the user to fill form

fields before displaying (use for interactive form-filling)

Returns a viewUUID — pass this to every interact call. Calling

display_pdf again creates a separate viewer; interact calls with

the new UUID won't reach the one the user is looking at.

Also returns formFields (name, type, page, bounding box) if the PDF

has fillable fields — use these coordinates for signature placement.

interact

All follow-up actions after display_pdf. Pass viewUUID plus one or

more commands. Batch multiple commands in one call via the

commands array — they run sequentially. End batches with

get_screenshot to verify changes visually.

Annotation actions:

• add_annotations — add markup (see types below)
• update_annotations — modify existing (id + type required)
• remove_annotations — delete by id array
• highlight_text — auto-find text by query and highlight it

(preferred over manual rects for text markup)

Navigation actions:

• navigate (page), search (query), find (query, silent),

search_navigate (matchIndex), zoom (scale 0.5–3.0)

Extraction actions:

• get_text — extract text from page ranges (max 20 pages). Use for

reading content to decide what to annotate, NOT for summarization.

• get_screenshot — capture a page as an image (verify your annotations)

Form action:

• fill_form — fill named fields: fields: [{name, value}, ...]

Annotation Types

All annotations need id (unique string), type, page (1-indexed).

Coordinates are PDF points (1/72 inch), origin top-left, Y increases

downward. US Letter is 612×792pt.

| Type | Key properties | Use for |

|------|----------------|---------|

| highlight | rects, color?, content? | Mark important text |

| underline | rects, color? | Emphasize terms |

| strikethrough | rects, color? | Mark deletions |

| note | x, y, content, color? | Sticky-note comments |

| freetext | x, y, content, fontSize? | Visible text on page |

| rectangle | x, y, width, height, color?, fillColor? | Box regions |

| circle | x, y, width, height, color?, fillColor? | Circle regions |

| line | x1, y1, x2, y2, color? | Draw lines/arrows |

| stamp | x, y, label, color?, rotation? | APPROVED, DRAFT, CONFIDENTIAL, etc. |

| image | imageUrl, x?, y?, width?, height? | Signatures, initials, logos |

Image annotations accept a local file path or HTTPS URL (no data:

URIs). Dimensions auto-detected if omitted. Users can also drag & drop

images directly onto the viewer.

Interactive Workflows

Collaborative annotation (AI-driven)

• display_pdf to open the document
• interact → get_text on relevant page range to understand content
• Propose a batch of annotations to the user (describe what you'll mark)
• On approval, interact → add_annotations + get_screenshot
• Show the user, ask for edits, iterate
• When done, remind them they can download the annotated PDF from the

viewer toolbar

Form filling (visual, not programmatic)

Unlike headless form tools, this gives the user **live visual

feedback** and handles forms with cryptic/unnamed fields where the

label is printed on the page rather than in field metadata.

• display_pdf — inspect returned formFields (name, type, page,

bounding box)

• If field names are cryptic (Text1, Field_7), get_screenshot

the pages and match bounding boxes to visual labels

• Ask the user for values using the visual labels, or infer from

context

• interact → fill_form, then get_screenshot to show the result
• User confirms or edits directly in the viewer

For simple well-labeled forms, display_pdf with

elicit_form_inputs: true prompts the user upfront instead.

Signing (visual, not certified)

• Ask for the signature/initials image path
• display_pdf, check formFields for signature-type fields or ask

which page/position

• interact → add_annotations with type: "image" at the target

coordinates

• get_screenshot to confirm placement

Disclaimer: This places a visual signature image. It is not a

certified or cryptographic digital signature.

Supported Sources

• Local files (paths under client MCP roots)
• arXiv (/abs/ URLs auto-convert to PDF)
• Any direct HTTPS PDF URL (bioRxiv, Zenodo, OSF, etc. — use the

direct PDF link, not the landing page)

Out of Scope

• Summarization / text extraction — use native Read instead
• Certified digital signatures — image stamping only
• PDF creation — this works on existing PDFs only