GPTs (custom versions of ChatGPT)
Japanese GPTs（カスタムGPT）
GPTs (custom GPTs) are versions of ChatGPT set up for one purpose with saved instructions, reference files, and chosen tools. OpenAI plans to retire them on December 11, 2026 and move them to plugins.
A GPT is a version of ChatGPT that already holds instructions (tone, goals, and things to avoid), reference files, and chosen tools such as web search. You do not have to repeat the same explanation each time, because it answers in the way you set up. It is like a staff member who was handed the work manual in advance. OpenAI's help pages also call them custom GPTs, and here GPT is a feature name, not a model name.
Watch out OpenAI plans to retire custom GPTs on December 11, 2026 and move them to plugins. Personal accounts such as Free and Plus can no longer create new ones. If you built a GPT, save its instructions and files in your own company documents too. Features that connect to outside services (actions) do not move over automatically.
Source: OpenAI Help Center, “GPTs in ChatGPT” · OpenAI Help Center, “Custom GPT retirement and migration FAQ” (checked 2026-10-26)