MD-Chat

A lightweight, fast desktop client for experimenting with OpenAI-compatible APIs. Built with egui for native performance and CommonMark support.

Features

• Fast native performance with egui
• Full Markdown rendering support
• Light/Dark mode toggle
• Persistent window position
• Compatible with OpenAI and similar APIs (like Reservoir)
• Clean, minimal interface

Configuration

MD-Chat uses a TOML config file for settings such as your OpenAI API key and API URL. Environment variables are no longer required.

Config File Location

• macOS: ~/Library/Application Support/MD-Chat/config.toml
• Linux: ~/.config/MD-Chat/config.toml

The config file is created automatically on first run if it does not exist.

Example config.toml

Copyopenai_api_key = "sk-...yourkey..."
api_url = "https://api.openai.com/v1/chat/completions"

• If openai_api_key is missing or empty, requests will fail unless the API does not require a key.
• You can edit this file to change your API key or use a different API URL.

Building and Running

Copy# Build the application
cargo build --release

# Run the application
cargo run --release

Usage

1. Launch the application
2. Type your message in the input box
3. Press Enter or click Send to submit
4. View the markdown-formatted response

Modal Editing & Vim-like Navigation

MD-Chat supports modal editing inspired by vim, making keyboard navigation fast and efficient:

• Modes:

  • INSERT: Type and edit your message as usual. Press Esc to enter NORMAL mode.
  • NORMAL: Keyboard navigation and commands. Press i or click the input box to return to INSERT mode.

• Navigation in NORMAL mode:

  • j / k: Scroll down/up by a small amount
  • Shift+j / Shift+k: Scroll down/up by one window height
  • g: Jump to the top
  • G: Jump to the bottom
  • r: Refresh chat history

• Other:

  • The current mode is shown in the top right, styled like vim.
  • The input box is always interactive; clicking it in NORMAL mode returns you to INSERT mode.

This makes MD-Chat a joy to use for keyboard-centric users and fans of modal editing!

Development

The codebase is organized into two main components:

• src/main.rs: UI and application logic
• src/openai.rs: API client implementation

Dependencies

• eframe: Egui framework for native applications
• egui_commonmark: Markdown rendering support
• reqwest: HTTP client
• tokio: Async runtime
• serde: Serialization/deserialization

License

Licensed under the BSD 3-Clause License. See the LICENSE file for details.