hexsecteam/HexSecGPT ? reverse-engineered prompt

Build me a simple Python app that acts like a command line AI chat tool. I want it to let me choose between OpenRouter and DeepSeek, ask for my API key the first time I run it, save that key locally, and then keep a smooth back and forth conversation in the terminal.

Please make it easy to install on Windows, Linux, and Termux, with a one step installer script if possible. Also include a small helper script that can show me which free OpenRouter models are currently available, since those can change over time. If a model stops working, I want the app to be easy to update with a different model name.

Keep the setup and usage really straightforward, and make the whole thing feel like a clean, lightweight chat framework rather than a big app. If you need to check current API or model details online, go ahead and look them up.