RAGs — Private Learning Tool

• Overview
• Prerequisites
  • Ollama
  • Nix
• Usage
  • LightRAG
  • Graphiti
  • Neo4j Management
• Configuration
  • .env.lightrag
  • .env.graphiti
• Structure
• Submodules

Overview

Two local RAG systems for a private learning tool with Anki export.

Project	Purpose
LightRAG	Graph-based RAG — ingest docs, query concepts
Graphiti	Temporal knowledge graph — track what you learned and when

Both run fully local via Ollama. No cloud, no API keys.

Prerequisites

Ollama

Install Ollama and pull the required models:

ollama pull qwen2.5:7b
ollama pull nomic-embed-text

Ollama must be running before starting either service.

Nix

Flakes must be enabled. Add to your NixOS config or ~/.config/nix/nix.conf:

experimental-features = nix-command flakes

Usage

LightRAG

Ingest documents and query them as a knowledge graph.

nix develop .#lightrag
lightrag-server

Server runs at http://localhost:9621.

Configure in .env.lightrag. Default storage is ./lightrag/rag_storage/.

Graphiti

Temporal memory graph — tracks concepts and when you learned them.

Start Neo4j first (in a separate terminal):

nix run .#neo4j-start

Then enter the shell:

nix develop .#graphiti

Configure in .env.graphiti.

Neo4j Management

nix run .#neo4j-start   # start daemon
nix run .#neo4j-stop    # stop daemon

Data persists in ./data/neo4j/. Web UI at http://localhost:7474.

Configuration

.env.lightrag

Variable	Default	Notes
LLM_BINDING	ollama
LLM_MODEL	qwen2.5:7b	Change to any Ollama model
EMBEDDING_MODEL	nomic-embed-text
EMBEDDING_DIM	768	Must match model
RAG_DIR	./rag_storage	Where graph data lives
PORT	9621

.env.graphiti

Variable	Default	Notes
NEO4J_URI	bolt://localhost:7687
OPENAI_BASE_URL	http://localhost:11434/v1	Ollama OpenAI-compatible API
OPENAI_API_KEY	ollama	Dummy value, required by SDK
MODEL_NAME	qwen2.5:7b
EMBEDDING_MODEL	nomic-embed-text
EMBEDDING_DIM	768	Must match model

Structure

rags/
├── flake.nix          — Nix devShells and neo4j apps
├── flake.lock
├── .env.lightrag      — LightRAG runtime config
├── .env.graphiti      — Graphiti runtime config
├── lightrag/          — submodule: hkuds/lightrag
├── graphiti/          — submodule: getzep/graphiti
├── data/
│   └── neo4j/         — Neo4j data (gitignored)
└── docs/
    └── setup.org      — How this was set up

Submodules

git submodule update --init --recursive