# NOT_IMPLEMENTED

URL: https://tailrace.dev/docs/reference/errors/NOT_IMPLEMENTED

> A specified surface is not implemented in this release.



## What it means [#what-it-means]

`NotImplementedError` (`code: NOT_IMPLEMENTED`). The API is typed or documented but not shipped yet.

## Message shape [#message-shape]

```text
<reason> → https://tailrace.dev/docs/reference/errors/NOT_IMPLEMENTED
```

## Common causes [#common-causes]

1. Policy action `review` (human-in-the-loop) - v0.2.
2. Other milestone-gated surfaces still throwing stubs.

## Fixes [#fixes]

1. Use `block`, `tokenize`, `mask`, or `allow` instead of `review`.
2. Check the package changelog / milestone docs for when the surface lands.

## Safe to catch? [#safe-to-catch]

At config validation time - treat as a config error and refuse to start with that policy.