Dedesfr/anvil-cli ? reverse-engineered prompt

Build me an open source AI coding agent called OpenCode that runs in the terminal and feels polished for real day to day coding.

I want a command line app where I can chat with an assistant, point it at a codebase, and let it help me explore, plan, and make changes. It should have two modes, one that can safely read and think through a project, and one that can actually edit files and run commands when I allow it. Make it easy to switch between those modes, and include a simple extra helper for bigger searches or multi step tasks.

Keep it provider agnostic so it can work with different AI models, and make the experience fast and clean in the terminal. If it makes sense, also add a basic desktop app version. Use the current best docs online if you need to check anything. I want something that feels like a real open source alternative to Claude Code, with strong terminal UX and practical defaults.