pdf-viewer-and-annotator-architecture

A set of project rules for building and changing PDF viewers and annotation features. It describes how the document knowledge base renders pages and manages annotations and relationships.

In plain words
What is it for?
Use it when changing PDF rendering, annotation tools, document search, knowledge extraction, or the hooks that control visible annotations and relationships.
Why use it?
It helps keep PDF-related frontend changes consistent and prevents filtering or rendering updates from working differently in different parts of the interface.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture
Clone the repo
git clone --depth 1 https://github.com/Open-Source-Legal/OpenContracts

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 2,830 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.02830
Opus 5 $0.00000 $0.01415
Sonnet 5 $0.00000 $0.00566
Haiku 4.5 $0.00000 $0.00283

Measured yesterday against content hash be6ebb9089e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

pdf-viewer-and-annotator-architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/pdf-viewer-and-annotator-architecture.mdc · 295 lines

How it starts

The opening of the file, as written. The whole thing — 295 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Understanding the PDF Annotation System Architecture

  1. When working on document knowledge base and pdf-related frontend functionality, ensure you update our cursor rule here pdf-viewer-and-annotator-architecture.mdc such that it captures any material changes to our existing setup.
  2. When modifying filtering logic, ensure changes are applied consistently to both useVisibleAnnotations and useVisibleRelationships hooks to maintain unified behavior.

Context: Document Knowledge Base

The DocumentKnowledgeBase component serves as the main container for viewing and interacting with documents, particularly PDFs. It provides a comprehensive interface that combines document viewing with annotation capabilities, search functionality, knowledge extraction features, and a sophisticated dual-layer architecture for both document annotation and knowledge synthesis.

The system uses a sophisticated virtualized rendering approach for PDFs, where only visible pages (plus a small overscan buffer) are rendered to dramatically improve performance with large documents. This is coupled with an advanced annotation management system that allows users to view, filter, and interact with annotations overlaid on the document.

Intent: High-Performance Document System with Dual-Layer Architecture

The architecture aims to:

  1. Efficiently render large PDF documents using virtualization (only visible pages are rendered)
  2. Provide a flexible annotation system that can display/hide annotations based on user preferences
  3. Support various annotation types (spans, tokens, structural elements)
  4. Enable real-time filtering and selection of annotations
  5. Maintain consistent state across the entire application using Jotai atoms
  6. Ensure smooth scrolling and navigation even with hundreds of pages
  7. Offer dual-layer architecture for document viewing and knowledge synthesis
  8. Provide unified content feeds combining notes, annotations, and relationships
  9. Support version-controlled document summaries with version history
  10. Enable flexible, resizable panel layouts with auto-minimize capabilities

Read the full file on GitHub · 295 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 295 lines · 2,830 tokens per session scan A be6ebb9089e1

Subscribe to this mod's changes

pdf-viewer-and-annotator-architecture is a cursor rule published in the GitHub repository Open-Source-Legal/OpenContracts (1,457 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,830 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.