LLM-State Contract — Schema Agreement Between App and AI

_↴ Ported from [flutter/genui#640](https://github.com/flutter/genui/issues/640) — originally opened by [leoafarias](https://github.com/leoafarias) on 2025-12-23._
_Original labels: front-line-handled_

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**Is your feature request related to a problem? Please describe.**
There is no agreement between app and AI about state structure. The LLM receives widget schemas but not a state manifest, so it guesses paths, can create arbitrary ones, and can vary paths between turns. Ownership of state structure (app vs. AI) is undefined.

**Describe the solution you'd like**
A defined state contract: a discoverable schema/manifest of allowed paths, plus guidance on ownership. Preferably, app state is the source of truth and `DataModel` is a derived view, with validation for path creation.

**Describe alternatives you've considered**
Letting the LLM create state freely, or constraining via prompt-only guidance. Both lead to brittle results (non-reactive UIs, invented paths, or inconsistent regeneration).

**Additional context**
Discussion: https://github.com/flutter/genui/discussions/609

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### 1 comment(s) from the original issue

**[yjbanov](https://github.com/yjbanov)** commented on 2025-12-29:

An agreement system between the app and the AI on data structure, but also read/write permissions, makes sense. Treating app state as the source of truth with `DataModel` being a derived view is an interesting idea. I can actually see this extending into a wider "BusinessModel" containing both data and business logic (actions/events), with structure and rules defined in a way that's easy to describe to the LLM (like we do for the widget catalog) and, crucially, easy to enforce (e.g. as part of upholding the required trust model and/or as protection for certains kinds of hallucinations).

リンクされた議論 #609 を確認し、現在の状態とウィジェットのスキーマシステムを理解してください。現在、DataModel がアプリの状態からどのように導出されているかを調査してください。目標は、状態パスと権限のためのスキーマ／マニフェストシステムを設計し、既存の LLM インタラクションモデルに統合することです。「Done」とは、状態コントラクトとその検証について提案された設計があることを意味します。

索引モデルが issue の本文から書いたものです。