> 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/4100-to-4106/aur0099.md).

# AUR0099

## Error Message

Development builds:

`AUR0099: Method <methodName> not implemented`

Production builds:

`AUR0099:<methodName>`

Where `<methodName>` is the name of the method that was called.

## Description

This error occurs when Aurelia (or an Aurelia-related extension point) reaches a method that is intentionally unimplemented for the current class/platform adapter, or when a custom implementation left a required method as a stub.

It typically indicates one of the following:

* A custom integration/plugin/adapter is missing an implementation.
* An unsupported code path was reached for the current environment.
* A bug/regression caused Aurelia to call a method that should not be reached.

## Example Trigger

```ts
class CustomAdapter {
  // ❌ Stub left behind
  public doWork(): never {
    throw new Error('AUR0099: Method doWork not implemented');
  }
}

new CustomAdapter().doWork();
```

## Correct Usage

* If you are implementing/overriding an Aurelia extensibility point, implement the required method instead of leaving a stub.
* If you are consuming Aurelia APIs, avoid relying on internal/private APIs; use the public API surface.

## Troubleshooting

* Use the stack trace to identify which method/class threw `AUR0099`.
* If the method is part of a custom integration, implement it or switch to a supported implementation.
* If it happens inside Aurelia internals on a supported environment, try upgrading and (if it persists) open an issue with a minimal reproduction.


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