OpenContracts is an open-source document intelligence platform that turns document collections into searchable citation graphs with annotations, structured extraction, and AI agents. Builders and teams use it to work with unstructured documents through APIs, an MCP server, or a web interface. The catalogue entries extend the platform with agent, instruction, and rule workflows.
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.
git clone --depth 1 https://github.com/Open-Source-Legal/OpenContractsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture)<a href="https://agentmods.dev/rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture"><img src="https://agentmods.dev/badge/rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture"><img src="https://agentmods.dev/badge/rules/open-source-legal/opencontracts/pdf-viewer-and-annotator-architecture.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.02830 | $0.02830 |
| Opus 5.5 | $0.01132 | $0.01132 |
| Sonnet 5.5 | $0.00566 | $0.00566 |
| Haiku 4.5 | $0.00283 | $0.00283 |
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 1mo ago.
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.
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
Admin Tasks if you Edit PDF-related frontend code
- 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.
- When modifying filtering logic, ensure changes are applied consistently to both
useVisibleAnnotationsanduseVisibleRelationshipshooks 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:
- Efficiently render large PDF documents using virtualization (only visible pages are rendered)
- Provide a flexible annotation system that can display/hide annotations based on user preferences
- Support various annotation types (spans, tokens, structural elements)
- Enable real-time filtering and selection of annotations
- Maintain consistent state across the entire application using Jotai atoms
- Ensure smooth scrolling and navigation even with hundreds of pages
- Offer dual-layer architecture for document viewing and knowledge synthesis
- Provide unified content feeds combining notes, annotations, and relationships
- Support version-controlled document summaries with version history
- Enable flexible, resizable panel layouts with auto-minimize capabilities
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.
- 1mo ago First seen · 295 lines · 2,830 tokens per session scan A be6ebb9089e1
pdf-viewer-and-annotator-architecture is a cursor rule published in the GitHub repository Open-Source-Legal/OpenContracts (1,508 stars, last pushed today), licensed MIT. It adds 2,830 tokens to every session, about $0.0113 per session on Opus 5.5. 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.
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