According to @NotebookLM, OpenAI has expanded the character limit for ChatGPT chat customization from 500 to 10,000 characters, allowing users to create significantly more detailed AI personas. This update enables advanced prompt engineering and tailored workflow automation, supporting use cases like product management, education, and scientific research. The change is expected to drive greater adoption of AI assistants in business, as organizations can now build complex, role-specific agents with nuanced instructions, improving productivity and decision support across industries. (Source: @NotebookLM on Twitter, Dec 4, 2025)

According to Sam Altman (@sama), most users will notice improvements in GPT-5 as the latest update rolls out over the next day. The update aims to enhance user satisfaction with GPT-5’s performance. Additionally, OpenAI is actively developing features that will let users customize ChatGPT's conversational style to better suit individual preferences, addressing a key area of user demand. This move highlights a growing trend in the AI industry toward greater personalization and user control, signaling business opportunities for companies to differentiate through customizable AI solutions (Source: Sam Altman on Twitter).