PageBrain

What is PageBrain?

PageBrain is an open-source chat text editor built for writing rather than databases, with a layout inspired by SQL Workbench. Brainstorming, writing, and rewriting happen in a single window, with ChatGPT integrated as a copilot alongside your text. You select text to rewrite, set a preferred writing style, and use built-in prompts for common writing tasks — no copying and pasting into a separate chat window.

The tool is built on Lexeme, a project created to streamline writing with ChatGPT, which also used SQL Workbench as its model.

How PageBrain is used

• Integrated writing workflow: Brainstorm, write, and rewrite in one place, with a layout inspired by SQL Workbench.
• Direct ChatGPT collaboration: Select text to send to ChatGPT and rewrite it without copying and pasting.
• Document-level writing style: Set a style in the document prompt; it applies to all subsequent chats, so you don’t repeat instructions.
• Built-in action prompts: Expand sentences, enforce word limits, add examples, brainstorm ideas, or create custom prompts.
• Reusable prompts: Ready-made prompts for writing OKRs, Slack messages, announcements, and managing projects.

How system prompts work

PageBrain uses three kinds of prompts — global, document, and action — to define context, model personality, and response formatting. Clear, concise system prompts help produce more relevant and accurate responses.