Chatgpt Tweak is a free Chrome add-on developed by lixianmin. This program allows you to customize prompts and quickly switch between message histories when using ChatGPT.

With Chatgpt Tweak, you can easily customize prompts by typing '/' in the text box, which will list the currently customized prompts. By selecting a specific prompt with your mouse, you can include it with each message you send to ChatGPT, enhancing your chat experience.

Additionally, Chatgpt Tweak provides a convenient way to switch between message history. By pressing the up and down arrow keys (↑↓) in the input box, you can easily navigate through your message history, making it effortless to adjust and resend previous messages.

Please note that Chatgpt Tweak has limited command support. By entering specific commands and pressing Enter, you can execute commands instead of sending a message to ChatGPT. Supported commands include 'help' to print help tips and 'history' to print the recent message list.

Furthermore, Chatgpt Tweak offers history command expansion similar to the Linux shell. By typing '!56' and pressing Enter, you can quickly input the 56th history command, saving you time and effort.

Lastly, the UI interface of Chatgpt Tweak supports both Chinese and English, providing a versatile experience for users.

Overall, Chatgpt Tweak is a useful Chrome add-on that allows you to customize prompts and easily switch message history when using ChatGPT.