zhristophe/Claude-Mythos-AI-Anthropic-App — reverse-engineered prompt

Build me an unofficial desktop chat app for Claude with a polished dark Mythos style, something that feels immersive for creative writing, roleplay, coding help, and long conversations.

The app should let me paste my own Anthropic API key on first launch, keep it private on my device, and then chat with Claude models like Sonnet and Opus with fast streaming replies. I want local chat history, ideally encrypted, plus a clean way to start new chats, continue old ones, and edit or reuse custom system prompts for different writing or reasoning modes.

Please include support for uploading images and documents if the Anthropic API allows it, and make the interface feel lightweight and modern rather than cluttered. It should be clear this is a third party app, not official Anthropic software, and it should warn users that API usage may cost money.

Look up the current Anthropic API docs online if you need to, and include simple setup and run instructions for regular users.