Should be about 10~20 GiB per session. Save/restore is exactly what DeepSeek does using its 3FS distributed filesystem: https://github.com/deepseek-ai/3fs#3-kvcache

With this much cheaper setup backed by disks, they can offer much better caching experience:

> Cache construction takes seconds. Once the cache is no longer in use, it will be automatically cleared, usually within a few hours to a few days.

What they mean when they say 'cached' is that it is loaded into the GPU memory on anthropic servers.

You already have the data on your own machine, and that 'upload and restore' process is exactly what is happening when you restart an idle session. The issue is that it takes time, and it counts as token usage because you have to send the data for the GPU to load, and that data is the 'tokens'.

> upload and restore it when the user starts their next interaction

The data is the conversation (along with the thinking tokens).

There is no download - you already have it.

The issue is that it gets expunged from the (very expensive, very limited) GPU cache and to reload the cache you have to reprocess the whole conversation.

That is doable, but as Boris notes it costs lots of tokens.

I often see a local model QWEN3.5-Coder-Next grow to about 5 GB or so over the course of a session using llamacpp-server. I'd better these trillion parameter models are even worse. Even if you wanted to download it or offload it or offered that as a service, to start back up again, you'd _still_ be paying the token cost because all of that context _is_ the tokens you've just done.

The cache is what makes your journey from 1k prompt to 1million token solution speedy in one 'vibe' session. Loading that again will cost the entire journey.