I've got a common spreadsheet with facts about me accessible to all personal agents, plus they consult each other, and it's a little disturbing how well it works. "You might want to spend a little more on a wood splitter that works vertically, to save your lower back." "That route will take you through an area with a high population of elk and deer at dusk, which is a particular hazard with your poor night vision." "You've been eating a lot of sauerkraut, shall I add more to this shopping list?"

While still disconcerting in my current state of future shock, it is so useful that I'd be willing to share selections with selected advertisers to get a better fit, e.g. from a personal MCP server. And then filter the results through agents to omit, e.g., offers for a wood chipper since I just bought one. Best if that's the only info they have about me so I can turn it off at will to anonymize.