Anyscale has developed a GitHub bot called "Docu Mentor" that analyzes writing style and grammar in pull requests. The bot uses a large language model (LLM) to provide suggestions for improvement, and can be triggered by comments such as "@docu-mentor run". To build the bot, developers must create a Ray Serve app with a FastAPI API definition, which is then deployed on Anyscale using a YAML file. Once deployed, the bot can be used to analyze PRs and provide feedback in the form of GitHub comments. The bot's performance was evaluated using GPT-4 as an evaluator, and found to be effective in identifying grammatical errors with a high degree of accuracy. To deploy the bot on GitHub, developers must create a new app with the correct permissions and settings, and link it to their repository.