Perplexity and Grok have had something like this for a while where you can make a workspace and write a pre-prompt that is tacked on before your questions so it knows that I use Arch instead of Ubuntu. The nice thing is you can do this for various different workspaces (called different things across different AI providers) and it can refine your needs per workspace.
Claude has this by way of projects, you can set instructions that act as a default starting prompt for any chats in that project. I use it to describe my project tech stack and preferences so I don't need to keep re-hashing it. Overall it has been a really useful feature to maintaining a high signal/noise ratio.
In Github Copilot's web chat it is personal instructions or spaces (Like perplexity), In CoPilot (M365) this is a notebook but nothing in the copilot app. In ChatGPT it is a project, in Mistral you have projects but pre-prompting is achieved by using agents (like custom GPT's).
These memory features seem like they are organic-background project generation for the span of your account. Neat but more of an evolution of summarization and templating.
