---
title: 'missing-field: Property is not bound'
editUrl: https://github.com/Cratis/Arc.TypeScript/edit/main/Documentation/code-analysis/missing-field.md
description: Mark every model-bound property with @field.
---


## What

A non-`declare` public instance property on `@command()` or `@readModel()` lacks `@field`. Rule: `arc-core/missing-field`.

## Why

Unmarked properties are invisible to Arc's wire schema. Private fields (`private` and `#`) and private-like `_` names are intentionally ignored.

## Bad

```ts
@command()
export class Register { title!: string; handle() {} }
```

## Good

```ts
@command()
export class Register { @field(String) title!: string; handle() {} }
```