Cache-to-Cache: Direct Semantic Communication Between LLMs (2025) (arxiv.org)
85 points by rochansinha 14 hours ago
ACCount39 12 hours ago
It's an old paper (from 2025, so, a decade ago in AI years), but the concept is still fascinating. And I'm yet to see it show up in any production models.
If multiple models can use cache representations for this kind of enrichment, the KV cache representations of different models must be somewhat compatible.
What stops us then from going a step further, and producing a model family where all models are "KV aligned", and each model can utilize the KV cache of other models directly?
So, an "expensive" reasoning model can use its full faculties to plan, but "delegate" simple subgoals to a smaller model. That smaller model can access the large model's intent directly, as rich KV cache representations - with no prefill recompute and no associated "handover" latency. Or, likewise, a "cheap" small model can generate a diminished but highly compact KV cache that the "expensive" model can then operate on - for example, for skimming a large file for shallow patterns.
refibrillator 11 hours ago
You might like The Universal Weight Subspace Hypothesis: https://arxiv.org/abs/2512.05117
Curious to know if anyone is aware of research trying what parent suggested?
ayewo 9 hours ago
Sounds similar to Ramp's Latent Briefing for multi-agent coordination.
gavinray 13 hours ago
A few months ago I asked why semantic representation rather than text wasn't used, since natural language seems quite a lossy representation for semantic concepts:
https://news.ycombinator.com/item?id=47195212
I wouldn't have thought to use it for LLM-to-LLM communication, though
foota 13 hours ago
I feel like multimodal models that can read images should work differently than they do. My understanding is that multimodal models basically first generate an image embedding and then the model is trained to interpret that embedding, but in the same way that text is lossy, it seems like the embedding would be as well. Why don't multimodal models learn to interpret images themselves without an embedding? Or e.g., by passing some "prompt" to the embedding model?
thfuran 12 hours ago
What does interpreting images mean in practice if you exclude the possibility of feature extraction or any other sort of implicit embedding?
foota 12 hours ago
I'm not an ML expert, but I was thinking of a sort of "guided" embedding. E.g., give the image model some prompt for what it's trying to do? I don't understand why multimodal models generate an embedding that doesn't understand what the model is trying to "figure out".
I think this is similar to how Gemma 4 12B is implemented, but even then I don't think the single layer image embedding is "aware" of the context.
cubefox 13 hours ago
So the models will not only be using more and more Neuralese in their CoT (like GPT-6), but different agents will also be able to communicate with each other in Neuralese. It's not looking good for monitorability.
sparky_twofort 12 hours ago
Is Neuralese in no way decodable into a human-interpretable system? Genuine question -- I don't know the answer.
Y_Y 12 hours ago
Definitely decodable, that's what's being done now
cubefox 10 hours ago
jephs 12 hours ago
This is from like a year ago.