RAG-Angular-Assistant: Implementation of an Offline RAG Assistant Based on Local LLaMA3 and FAISS

This open-source project is developed by NA Eswari, aiming to build a fully offline Retrieval-Augmented Generation (RAG) assistant for Angular technical documentation Q&A scenarios. The core tech stack includes LLaMA3 (local large model), FAISS (vector database), HuggingFace embedding model, LangChain (process orchestration), and Ollama (local LLM runtime). It does not rely on external AI APIs, solving issues of data privacy, network dependency, cost, and vendor lock-in.

Traditional RAG relying on commercial APIs has issues like data privacy risks (sensitive data sent to third parties), network dependency (unusable offline/intranet), cumulative costs (high fees for frequent calls), and vendor lock-in. Local RAG systems can effectively address these pain points, and this project is a practical example.

The project uses a modular architecture with core components including:

1. Embedding Layer: HuggingFace Transformers (local embedding model, data never leaves the local environment)
2. Vector Storage: FAISS (high-performance open-source vector search library, stored in local files)
3. Inference Engine: Ollama + LLaMA3 (simplifies local model management and invocation)
4. RAG Orchestration: LangChain (coordinates the entire process, components are replaceable)

The system is divided into two main phases: document ingestion and query processing:

1. Document Ingestion: Run ingest.py to load documents → split text → generate embeddings → store in FAISS index
2. Query Processing: User asks a question → convert question to embedding → FAISS semantic retrieval → build context prompt → Ollama calls LLaMA3 to generate answer

The project controls hallucinations through strict prompt engineering: it requires the model to answer only based on the retrieved context, and return "I don't know" if information is insufficient, avoiding fabricated answers and improving system credibility, which is suitable for technical documentation Q&A scenarios.

Application scenarios include enterprise internal knowledge bases, developer tool documentation Q&A, offline learning assistance, etc. Future plans include adding PDF ingestion, multi-document retrieval, Streamlit interface, conversation memory, LangGraph workflow, and other features.

This project proves that:

• Consumer-grade hardware can run a fully offline RAG system
• Open-source toolchains (LangChain + FAISS + Ollama) support production-level applications
• Prompt engineering can effectively control model hallucinations It has reference value for teams concerned about privacy, cost, and offline availability.