questmind 0.3.2

Local VLM server and document processor for Apple Silicon

questmind

Local VLM server and document processor for Apple Silicon

Features

• OpenAI-compatible API - Run local VLMs via HTTP with streaming
• Document processing - PDFs, image collections, text files
• Hybrid intelligence - Native text extraction + VLM for visual content
• Multi-turn caching - KV prefix cache, vision embedding cache
• Apple Silicon optimized - MLX backend with Metal acceleration
• Self-contained - No external fork dependencies

Requirements

• Python 3.10+
• macOS with Apple Silicon (M1/M2/M3/M4)
• 16GB+ RAM recommended (32GB+ for 30B models)

Installation

# Add to your project (creates .venv automatically)
uv add questmind

# Or run directly without installing
uvx questmind --help

# From source
git clone https://github.com/lubauss/questmind.git
cd questmind
uv sync

Command	Purpose	What it does
uv add questmind	Add dependency	Creates .venv, updates pyproject.toml, generates uv.lock
uv run questmind serve	Run CLI	Uses project's venv, auto-syncs deps
uvx questmind	Run without install	Ephemeral environment, like npx
uv sync	Install from lockfile	Reproducible builds from uv.lock

All features (VLM server, PDF/image processing, embeddings) are included by default.

Quick Start

Server Mode

# Start the VLM server
uv run questmind serve --model mlx-community/Qwen3-VL-4B-Instruct-4bit --port 8000

# With continuous batching (better for multiple users)
uv run questmind serve --model mlx-community/Qwen3-VL-4B-Instruct-4bit --continuous-batching

# Query via curl
curl http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{"model": "default", "messages": [{"role": "user", "content": "Hello!"}]}'

Vision Queries

# Image from URL
curl http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "default",
    "messages": [{
      "role": "user",
      "content": [
        {"type": "text", "text": "What is in this image?"},
        {"type": "image_url", "image_url": {"url": "https://example.com/image.jpg"}}
      ]
    }]
  }'

Document Processing

# Ingest a document
uv run questmind ingest document.pdf --output doc.pack

# Query a document
uv run questmind query doc.pack "What is this about?"

Library Mode

from questmind import PDFIngestor, QueryEngine

# Ingest a PDF
pack = PDFIngestor().ingest("document.pdf")

# Query with RAG
result = QueryEngine().query(pack, "What is the main topic?")
print(result.answer)
print(f"Pages used: {result.pages_used}")
print(f"Method: {result.method}")  # "text_only" or "text_with_vision"

Supported Models

Model	Size	Memory	Use Case
mlx-community/Qwen3-VL-2B-Instruct-4bit	2B	~4GB	Quick responses
mlx-community/Qwen3-VL-4B-Instruct-4bit	4B	~6GB	Balanced
mlx-community/Qwen3-VL-8B-Instruct-4bit	8B	~10GB	High quality
mlx-community/Qwen3-VL-30B-A3B-Instruct-4bit	30B MoE	~20GB	Best quality

Performance

Tested on MacBook Pro M4 Max 128GB with Qwen3-VL-30B-A3B:

Metric	Value
Generation TPS	70-75 tok/s
Prompt TPS (cached)	1200-1500 tok/s
Prompt TPS (cold)	400-700 tok/s
Multi-turn speedup	2-21x

Architecture

questmind/
├── server/          # OpenAI-compatible FastAPI server
├── engine/          # Simple + Batched inference engines
├── models/          # Qwen3-VL model implementations
├── inference/       # Generation, sampling, tokenization
├── cache/           # KV prefix cache, VLM cache
├── scheduler/       # Continuous batching scheduler
└── api/             # Pydantic models, utilities

Caching Layers

Cache	Purpose	Benefit
KV Prefix	Reuse computed attention states	2-21x speedup
Vision Embedding	Skip vision encoder on repeated images	1.3-1.7x speedup
Cross-image Prefix	Reuse text prefix across images	Multi-image support

API Reference

Server Endpoints

Endpoint	Method	Description
/v1/chat/completions	POST	Chat completions (streaming)
/v1/completions	POST	Text completions
/v1/models	GET	List available models
/health	GET	Health check
/metrics	GET	Server metrics

Python API

# Server (programmatic)
from questmind.server import app, load_model
load_model("mlx-community/Qwen3-VL-4B-Instruct-4bit")
# Run with: uvicorn questmind.server:app

# Direct inference
from questmind.inference import load, generate
model, processor = load("mlx-community/Qwen3-VL-4B-Instruct-4bit")
output = generate(model, processor, "Hello!")

# Document processing
from questmind import PDFIngestor, ImageIngestor, TextIngestor, QueryEngine
pack = PDFIngestor().ingest("doc.pdf")
result = QueryEngine().query(pack, "Summary?")

Environment Variables

Variable	Default	Description
QUESTMIND_API_KEY	None	API key for authentication
QUESTMIND_CACHE_DIR	~/.questmind/cache	Cache directory
MLX_METAL_DEVICE	0	GPU device index

Changelog

v0.3.0 (2026-01-26)

• Integrated vllm-mlx and mlx-vlm - No more fork dependencies
• Self-contained package with single pip install
• Qwen3-VL models (dense and MoE) included
• Simplified installation and deployment

v0.2.0

• Added CLI commands (serve, ingest, query)
• Backend selection (mlx/cuda)
• Multi-turn caching improvements

v0.1.0

• Initial release
• PDF processing with hybrid VLM
• RAG pipeline with embeddings

License

MIT

Credits

Built on:

• MLX - Apple's ML framework
• mlx-lm - Language model primitives
• mlx-vlm by @Blaizzy - Vision-language model inference
• vllm-mlx by @waybarrios - MLX inference server with continuous batching
• Qwen3-VL - Vision-language models