System Prompt Builder

System Prompt Builder turns a short form into a paste-ready system prompt for ChatGPT Custom Instructions or Claude Projects. Choose a mode, fill the form, build, copy and paste. Preset roles include Research bot, Support bot and Content bot. It only formats text, with no API call, and is aimed at English-speaking solo founders.

The builder is free, with no account, no credits and no paywall. Everything runs in your browser, and when you close the tab the text is gone. The site also promotes a separate paid AI Bot Workflow Template Pack.