docs(readme): refresh project overview

README.md

@@ -1,53 +1,200 @@
 # RAG Memory Assistant
 
-Local-first RAG + Memory assistant for private knowledge-base Q&A.
+A local-first knowledge-base Q&A assistant that helps you ask questions over your own
+documents, get grounded answers with citations, and keep a lightweight history of previous
+interactions.
+
+## What It Does
+
+RAG Memory Assistant lets you build a private knowledge base from local materials such as
+papers, articles, code files, and notes. After ingestion, you can ask questions through a web
+UI or API, and the assistant answers using retrieved source chunks instead of relying only on
+model memory.
+
+Core capabilities:
+
+- Ingest local documents into a searchable knowledge base
+- Retrieve relevant context with hybrid search and reranking
+- Generate grounded answers with source citations
+- Keep basic interaction history and feedback
+- Use either a Streamlit web UI or FastAPI endpoints
+- Run offline evaluation to measure answer quality
+
+## How It Works
+
+```text
+Documents
+  -> parsing and chunking
+  -> embeddings + vector storage
+  -> BM25 keyword index
+  -> hybrid retrieval
+  -> reranking
+  -> prompt assembly
+  -> LLM answer with citations
+  -> interaction history
+```
+
+The system combines vector search, keyword search, and reranking before sending retrieved
+sources to the language model. Answers are expected to cite the provided source chunks.
+
+## Architecture
+
+```text
+Streamlit UI
+  -> FastAPI API
+    -> Ingestion pipeline
+    -> Retrieval pipeline
+    -> Generation pipeline
+    -> Memory/history store
+
+Storage:
+  - Qdrant for vector search
+  - BM25 index for keyword search
+  - SQLite for document metadata and interaction history
+```
+
+## Tech Stack
 
-See root documentation files and `docs/` for project documentation.
+| Layer | Technology |
+|---|---|
+| UI | Streamlit |
+| API | FastAPI + Uvicorn |
+| Package manager | uv |
+| Vector database | Qdrant |
+| Keyword search | rank-bm25 |
+| Embeddings | AIHubMix OpenAI-compatible API |
+| Reranking | Cohere rerank |
+| LLM providers | DeepSeek and OpenRouter |
+| Memory store | SQLite + SQLAlchemy async |
+| Observability | Langfuse + loguru |
+| Evaluation | RAGAS |
+| Runtime | Docker Compose |
 
-## Setup
+## Quick Start
+
+### 1. Configure Environment
 
 ```bash
-# 1. 复制环境变量
 cp .env.example .env
-# 编辑 .env 填入 API keys
+```
 
-# 2. 装依赖
-uv sync
+Fill in the required API keys in `.env`.
 
-# 3. 启动 Qdrant
-docker compose up -d
+### 2. Run With Docker
 
-# 4. 验证连通
-python scripts/test_llm.py
+```bash
+docker compose up --build
 ```
 
-## Run
+Open:
+
+- Web UI: http://localhost:8501
+- API docs: http://localhost:8000/docs
+- Health check: http://localhost:8000/health
+
+### 3. Local Development Mode
+
+If you are editing prompts or backend code, run Qdrant in Docker and run the app locally:
 
 ```bash
-# CLI
-python scripts/ask.py "what is attention"
+docker compose up -d qdrant
+uv sync
+uv run uvicorn src.api.main:app --reload --port 8000
+```
 
-# API
-uvicorn src.api.main:app --reload
+In another terminal:
 
-# UI
-streamlit run ui/app.py
+```bash
+uv run streamlit run ui/app.py
 ```
 
-## Docker
+Then open:
+
+```text
+http://localhost:8501
+```
+
+## Using The App
+
+### Ingest Documents
+
+Use the `Documents` page in the web UI to upload and ingest files.
+
+You can also ingest from the command line:
 
 ```bash
-docker compose up --build
+uv run python scripts/ingest_one.py data/raw/example.pdf --type paper
 ```
 
-- UI: http://localhost:8501
-- API docs: http://localhost:8000/docs
-- Health: http://localhost:8000/health
-- Docker image excludes offline evaluation dependencies such as RAGAS.
+### Ask Questions
+
+Use the `Chat` page in the web UI, or run:
+
+```bash
+uv run python scripts/ask.py "What is self-attention?"
+```
+
+Answers include citations when the model references retrieved sources.
+
+### Review History
+
+Use the `History` page to inspect previous questions, answers, citations, feedback, and costs.
 
 ## Evaluation
 
+Evaluation is an offline workflow and is not included in the runtime Docker image by default.
+
+Install evaluation dependencies:
+
 ```bash
 uv sync --extra eval
-uv run --extra eval python eval/run_eval.py --help
 ```
+
+Run an evaluation:
+
+```bash
+uv run --extra eval python eval/run_eval.py --tag baseline
+```
+
+Results are written to:
+
+```text
+eval/results/<tag>/
+```
+
+See `docs/09-eval.md` for details.
+
+## Current Status
+
+RAG Memory Assistant currently supports a working local-first RAG workflow: document ingestion,
+hybrid retrieval, reranking, grounded answer generation, source citations, basic interaction
+history, a web UI, an API, and offline evaluation.
+
+Future versions may explore more advanced memory and learning-assistant capabilities:
+
+- Fine-grained user profiles and long-term memory
+- Extracting durable facts from conversations
+- Abstracting concepts across documents and interactions
+- Tracking learning progress and concept mastery
+- Recommending reviews or follow-up materials
+- Handling memory conflicts, updates, and decay
+- Improving retrieval through Self-RAG query rewriting
+- Expanding observability across retrieval, generation, and memory
+
+## Documentation
+
+Detailed design docs live in `docs/`:
+
+- `docs/03-ingestion.md` - ingestion pipeline
+- `docs/04-retrieval.md` - retrieval and reranking
+- `docs/05-generation.md` - prompt and generation design
+- `docs/06-memory.md` - interaction history and memory
+- `docs/07-api.md` - API design
+- `docs/08-observability.md` - Langfuse and logging
+- `docs/09-eval.md` - evaluation workflow
+
+Implementation task notes live in `docs/task/`.
+
+## License
+
+TBD