I've built a memory layer where the store isn't written by any model. It holds the conversation itself, so nothing in it is shaped by whichever model happened to be running at the time.

The practical effect is that you can switch model mid-conversation and nothing underneath changes. No rebuild, no re-extraction, no separate memory per provider. One model answers, then another answers the next turn, and both are reading the same thing. It's a dropdown, not a migration.

It also means the cost is predictable. Around 2,000 tokens of context per question regardless of which model is answering, and the retrieval itself takes about a second and a half before the model starts writing.

What I want to know is whether the product around it is something people want.

Right now if you're serious about this stuff you're paying for two or three subscriptions, working in as many tabs, and carrying context between them yourself. I've assumed that's annoying enough that one place with one memory would be better.  
Is that true for you, or do you actually prefer keeping them separate?

The demo is just to give you an idea. Thanks.

One memory that works across any model. Would you actually want all of them in one place?