Kurozu

Design philosophies

Context layer design notes

Ideas driving the design and implementation of the Kurozu app, specifically the context layer.

The app's goal and two layer design.

As AI becomes part of everyday life, we all hope to get health information that is both scientifically grounded and personally relevant. We think about and implement this in 2 layers: Context layer and Experience layer.

  • Context layer: facts, timeline, health background, wearable/lab data, etc., all in one exportable context object.
  • Experience layer: research, summaries, doctor prep, feeds, and other outputs built on top of that context.

The missing layer

AI systems are getting better at text, health, biology, research, and reasoning. The bottleneck is increasingly not only model capability.

What's missing: an easy way to input, structure, visualize, edit, and carry personal health context across AI systems.

It is the small missing non-AI component around AI:

Existing health signals are useful but incomplete/noisy

Labs, wearables, genetics, clinical records, and trackers all matter. But they are noisy, partial, expensive, burdensome, etc..

Quantified signals alone cannot yet produce good personalization.

Natural-language facts are a good health data format

People do not remember health history as perfect structured data. That is fine.

Vague, partial, subjective-feeling descriptions can still be extremely valuable:

Natural text is the native format for nuance, uncertainty, and variable granularity. LLMs make this format newly practical because they are good at processing text in high volume and connecting dots.

The core object: a good-enough personal timeline

A good-enough timeline is:

It should separate:

Facts are not interpretations

If a user says:

“I started iron in March and felt less tired later. Maybe iron helped.”

The system may extract:

It should not extract:

Extraction AI is thin and optional

The extraction AI for adding new facts is just an input helper.

It helps turn messy text or voice into editable candidate facts. It is not the source of truth. The timeline and facts are the source of truth.

In local-only mode, users should still be able to manually create and edit the timeline without AI.

The main AI vision goes to the Experience layer

The more ambitious AI belongs above the personalization layer.

The personalization layer creates a portable context object. That object can later power:

The app should not lock the user’s health context into one AI / agent.

Portability

The Context layer should be easy to export and merge with other signals.

Natural-language facts can be combined with:

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