Inspiration

As large language models become more powerful, connecting them to personal or enterprise data becomes essential for contextual reasoning. However, sending raw files—including sensitive content—to cloud-based APIs raises significant privacy concerns. We were inspired to bridge this gap by building a system that could preserve privacy without sacrificing the utility of intelligent, cloud-based reasoning.

What it does

LlamaGuard is a secure preprocessing layer built on top of the Model Context Protocol (MCP). It runs locally and performs intelligent summarization, filtering, and formatting of local files before any data is sent to external LLMs. It supports diverse file types (e.g., .pptx, .jpeg, .pdf), detects and redacts sensitive content, and outputs standardized JSON ready for MCP ingestion.

How we built it

We built a custom MCP server that takes in local file directories, runs them through a local instance of the LLaMA model using Llama stack, and processes each file via summarization, privacy classification, and formatting. We designed a JSON schema to represent file content in a compressed and structured manner, allowing for compatibility with downstream LLM systems. Key components include:

  • Llama stack for running LLaMA locally

  • File parsers for diverse formats (.docx, .pptx, .csv, .jpeg, .pdf)

  • Privacy filtering and summarization modules

  • A formatting pipeline that outputs structured JSON

Challenges we ran into

  • Building a flexible pipeline that could handle diverse file types consistently

  • Designing a privacy detection system that balanced accuracy with speed

  • Ensuring summaries retained semantic context while significantly reducing file size

  • Integrating the LLaMA stack locally without sacrificing runtime performance

Accomplishments that we're proud of

  • Successfully preprocessing and summarizing over a gigabyte of mixed-format files

  • Building a privacy-aware system that detects and redacts sensitive information automatically

  • Supporting real-world file formats like images and presentations, which typical MCP servers ignore

  • Creating a scalable and secure JSON output format ready for downstream use

What we learned

  • Local model inference (especially with LLaMA) is viable and powerful when optimized correctly

  • Privacy filtering and summarization are essential preprocessing steps in real-world AI systems

  • Building useful AI infrastructure requires both thoughtful architecture and deep understanding of real-world user data constraints

What's next for LlamaGuard

We plan to extend LlamaGuard to support real-time file monitoring, allowing agents to dynamically ingest new local context. We also aim to incorporate multimodal reasoning capabilities (e.g., better vision-language summarization), tighter integration with agent frameworks, and fine-grained user control over what content gets processed or shared. In the long term, LlamaGuard could become a core layer in privacy-preserving AI systems, both personal and enterprise-grade.

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