> For the complete documentation index, see [llms.txt](https://docs.aurelia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aurelia.io/developer-guides/error-messages/runtime-html/aur0714.md).

# AUR0714

## Status: Removed

This error code has been removed from Aurelia 2. The `primary` property on bindable definitions no longer exists.

## Previous Error Message

`AUR0714: Template compilation error: primary already exists on element/attribute "<name>"`

## Migration

In previous versions of Aurelia 2, you could mark a bindable property as `primary: true` to indicate which property should receive values when using shorthand syntax. This could cause conflicts if multiple bindables were marked as primary.

This has been replaced with the `defaultProperty` option on the custom attribute definition, which is a single string property that cannot conflict.

**Old API (no longer supported):**

```typescript
import { bindable, customAttribute } from 'aurelia';

@customAttribute('my-attr')
export class MyAttribute {
  @bindable({ primary: true }) value: string;
  @bindable other: string;
}
```

**New API:**

```typescript
import { bindable, customAttribute } from 'aurelia';

@customAttribute({ name: 'my-attr', defaultProperty: 'value' })
export class MyAttribute {
  @bindable value: string;
  @bindable other: string;
}
```

The `defaultProperty` option specifies which property receives the value when the attribute is used with shorthand syntax. If not specified, it defaults to `'value'`.

See the [Custom Attributes documentation](https://github.com/aurelia/aurelia/blob/master/templates/custom-attributes.md#default-property) for more details.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.aurelia.io/developer-guides/error-messages/runtime-html/aur0714.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.