mlx-dev-server 0.1.2

A server to run MLX models locally, optimized for code completion

MLX Dev Server

Installation | Usage | Examples

A simple solution to run LLMs locally on Macs with Apple Silicon. Optimized for code completion tasks with DeepSeek, Qwen and other models.

Features

• 🚀 Fast: uses Apple MLX to run models on GPU using unified memory
• 💪 Efficient: cancels generation when client disconnects (see Motivation on why it is important for code completion)
• 🧩 Compatible: provides OpenAI-like API to easily integrate with existing applications (see Examples)
• 💾 Memory Efficient: unloads models when they are not used
• 🔗 Reliable: test coverage is 97%

Motivation

While Ollama is effective for many tasks, it can be less responsive for code completion due to its handling of prompt processing.

Code completion requires quick processing of large inputs (1k+ tokens) and short output generation (<100 tokens typically). And most completions are cancelled because developers often pause for a moment and continue typing, discarding the completion. Ollama processes the entire prompt before cancellation, leading to potential delays.

MLX Dev Server addresses this by cancelling both prompt processing and generation when the client disconnects, ensuring consistent and responsive code completion.

Installation

pip install mlx-dev-server

Usage

Simply run mlx_dev_server.

Available command line arguments:

• -p, --port: Port to listen on (default is 8080)
• -k, --keep-alive: Time in seconds to keep models loaded in memory (default is 300)
• -m, --max-loaded-models: Maximum number of models to keep loaded (default is 2)
• --host: Host to listen on (default is localhost)
• --max-tokens: Maximum tokens to generate if not specified (default is 4096)
• --max-kv-size: Maximum size of the key-value cache (default is 4096)
• --prefill-step-size: Step size for prompt processing (default is 128)

Examples

VSCode

Install llm-vscode extension. Then add the following to settings.json:

{
    "llm.backend": "openai",
    "llm.url": "http://localhost:8080",
    "llm.modelId": "mlx-community/DeepSeek-Coder-V2-Lite-Instruct-4bit-mlx",
    "llm.configTemplate": "Custom",
    "llm.requestBody": {
        "parameters": {
            "temperature": 0.2,
            "top_p": 0.95,
            "max_tokens": 60
        }
    },
    "llm.fillInTheMiddle.prefix": "<｜fim▁begin｜>",
    "llm.fillInTheMiddle.middle": "<｜fim▁end｜>",
    "llm.fillInTheMiddle.suffix": "<｜fim▁hole｜>",
    "llm.tokenizer": {
        "repository": "mlx-community/DeepSeek-Coder-V2-Lite-Instruct-4bit-mlx"
    },
    "llm.contextWindow": 1024
}

[!NOTE] This configuration limits the number of generated tokens to 60. This is to speed up the response of the model if it decides to generate a multi-line code snippet.

Neovim

Add the following spec to lazy.nvim configuration to enable llm.nvim plugin:

{
  'huggingface/llm.nvim',
  opts = {
    backend = 'openai',
    url = 'http://localhost:8080',
    model = 'mlx-community/DeepSeek-Coder-V2-Lite-Instruct-4bit-mlx',
    request_body = {
      temperature = 0.2,
      top_p = 0.95,
      max_tokens = 60
    },
    fim = {
      prefix = '<｜fim▁begin｜>',
      middle = '<｜fim▁end｜>',
      suffix = '<｜fim▁hole｜>'
    },
    tokenizer = {
      repository = 'mlx-community/DeepSeek-Coder-V2-Lite-Instruct-4bit-mlx'
    },
    context_window = 1024
  }
}

OpenAI Python API library

from openai import OpenAI

client = OpenAI(
    base_url='http://localhost:8080/v1',
    api_key='mlx-dev-server',  # not needed but required
)

response = client.chat.completions.create(
    model='mlx-community/Mistral-Nemo-Instruct-2407-8bit',
    messages=[{
        'role': 'user',
        'content': 'say hello',
    }],
)
print(response.choices[0].message.content)