Recall

RAG-powered knowledge base assistant. Upload your documents, ask anything — get accurate, source-cited answers in real time.

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Tech Stack

Layer	Technology
Frontend	React 18 · TypeScript · Vite · UnoCSS
Backend	FastAPI · Python 3.11
RAG	LangChain · ChromaDB
LLM	Anthropic Claude API
Streaming	Server-Sent Events (SSE)

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Features

• 📄 Upload PDF / Markdown / TXT documents
• 🔍 Hybrid retrieval — vector search + BM25, fused via RRF
• ⚖️ Two-stage rerank — recall Top-20, rerank to Top-5
• 💬 Streaming answers with source citations
• 🚫 Hallucination-resistant — refuses to answer outside context

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Getting Started

Prerequisites

• Python 3.11+
• Node.js 18+
• Anthropic API key

Backend

cd backend
python -m venv .venv
source .venv/bin/activate      # Windows: .venv\Scripts\activate
pip install -r requirements.txt

cp .env.example .env
# Add your ANTHROPIC_API_KEY to .env

uvicorn main:app --reload --port 8000

Frontend

cd frontend
npm install
npm run dev                    # http://localhost:5173

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Docker

# Copy and fill in your API key first
cp .env.example .env

docker compose up --build

Services:

• Frontend → http://localhost:5173
• Backend → http://localhost:8000

docker-compose.yml mounts ./data for ChromaDB persistence.

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API

Base URL: http://localhost:8000/api

Upload document

POST /documents/upload
Content-Type: multipart/form-data

file: <PDF | TXT | MD>

{ "doc_id": "abc123", "chunk_count": 24, "status": "ok" }

List documents

GET /documents

[{ "doc_id": "abc123", "filename": "handbook.pdf", "chunk_count": 24, "created_at": "2026-02-22T10:00:00Z" }]

Delete document

DELETE /documents/{doc_id}

Chat (streaming)

POST /chat/stream
Content-Type: application/json

{ "query": "string", "doc_ids": ["abc123"], "history": [] }

SSE response stream:

data: {"type": "token",   "content": "Based on..."}
data: {"type": "sources", "sources": [{"text": "...", "score": 0.91, "source": "handbook.pdf"}]}
data: {"type": "done",    "usage": {"input_tokens": 480, "output_tokens": 212}}

Health check

GET /health

{ "status": "ok", "doc_count": 3, "vector_count": 72 }

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Project Structure

recall/
├── backend/
│   ├── main.py
│   ├── routers/
│   │   ├── chat.py
│   │   └── documents.py
│   ├── services/
│   │   ├── rag_service.py
│   │   ├── embedding.py
│   │   └── llm_service.py
│   ├── models/schemas.py
│   └── requirements.txt
├── frontend/
│   ├── src/
│   │   ├── components/
│   │   ├── stores/
│   │   └── hooks/
│   ├── vite.config.ts
│   └── uno.config.ts
├── docker-compose.yml
└── .env.example

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Environment Variables

# .env.example
ANTHROPIC_API_KEY=sk-ant-...
CHROMA_PERSIST_DIR=./data/chroma
CHUNK_SIZE=512
CHUNK_OVERLAP=50
RETRIEVAL_TOP_K=20
RERANK_TOP_N=5

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Contributing

1. Fork the repo
2. Create a feature branch — git checkout -b feat/your-feature
3. Commit with conventional commits — feat: / fix: / docs:
4. Open a pull request

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License

MIT