Interactive PDF viewer. Use when the user wants to open, show, or view a PDF and collaborate on it visually — annotate, highlight, stamp, fill form fields,…
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 onlydon't have the plugin yet? install it then click "run inline in claude" again.