Citation Sentinel

A source-grounded research assistant inspired by Google's NotebookLM. MIT license, by @sjdev. Users upload documents, links, youtube videos, ask questions and receive answers (with inline citations) grounded in their sources.

Built with a React/Vite frontend and a Node.js/Express backend, using Anthropic Claude for generation, OpenAI Whisper for video audio track transcription, Voyage AI for embeddings and response cosine similarity scoring ("groundedness" score).

Prerequisites

Node.js (v18+)
yt-dlp -- required for YouTube video source support (brew install yt-dlp or pip install yt-dlp)

Getting Started

# clone and install
git clone <repo-url> && cd notebooklm_clone
cd server && npm install && cd ..
cd client && npm install && cd ..

# configure
cp server/.env.example server/.env
# edit server/.env and add your ANTHROPIC_API_KEY, VOYAGE_API_KEY,
# and optionally OPENAI_API_KEY (only needed for audio source transcription via Whisper)

# run
make dev

Rationale

NotebookLM is a powerful research tool, but it is proprietary and closed. This clone demonstrates the core source-grounded Q&A pattern with transparent retrieval, generation, and groundedness scoring (LLM response quality cosine scoring) -- all with swappable models/fully open source.

Design

Two-package monorepo:

server/ -- single Express backend with layered architecture (routes -> services -> stores). Routes orchestrate; services contain business logic; stores manage in-memory state.
client/ -- React 19 SPA via Vite. Two-panel layout: sidebar for notebooks/data sources, main area for LLM chat with explorable citations, groundedness badges (cosine similarity scoring of LLM responses), and follow-up question chips.

Query pipeline

Embed query (Voyage) -> k-NN search -> rerank (Voyage) -> generate answer with citations (Claude) -> compute groundedness score (cosine similarity of answer vs cited chunks).

License

MIT. See LICENSE.

Author

@sjdev

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