# existence

Checks

existence

## existence

Learn about the existence extension point.

| Name         | Type    | Description                                                                                        |
| ------------ | ------- | -------------------------------------------------------------------------------------------------- |
| `append`     | `bool`  | Adds `raw` to the end of `tokens`, assuming both are defined.                                      |
| `ignorecase` | `bool`  | Makes all matches case-insensitive.                                                                |
| `nonword`    | `bool`  | Removes the default word boundaries (`\b`).                                                        |
| `action`     | `array` | Options for correcting matches, see the [actions](/topics/actions.md) section.                     |
| `raw`        | `array` | A list of tokens to be concatenated into a pattern.                                                |
| `tokens`     | `array` | A list of tokens to be transformed into a non-capturing group.                                     |
| `exceptions` | `array` | An array of strings to be ignored.                                                                 |
| `vocab`      | `bool`  | If false, disables all active [vocabularies](/keys/vocabularies.md) for this rule (default: true). |

The most general extension point is existence. As its name implies, it looks for the “existence” of particular tokens.

```yaml
extends: existence
message: Consider removing '%s'
level: warning
ignorecase: true
tokens:
  - appears to be
  - arguably
```

These tokens can be anything from simple phrases (as in the above example) to regular expressions—e.g., [the number of spaces between sentences](https://github.com/errata-ai/vale/blob/master/testdata/styles/demo/Spacing.yml) or [the position of punctuation after quotes](https://github.com/errata-ai/Google/blob/master/Google/Quotes.yml).

### [tokens](#tokens)

{% hint style="info" %}
Heads up!

See [Vale Studio](https://studio.vale.sh/) for a live editor that can help you write and test your rules, including generating the compiled regular expression.
{% endhint %}

The most common entry point for this extension point is the `tokens` key, which is a list of strings or regular expressions to be transformed into a word-bounded, non-capturing group:

```yaml
tokens:
  - appears to be
  - arguably
```

Which, after compilation, becomes:

```regex
(?i)(?m)\b(?:appears to be|arguably)\b
```

This is a convenience feature to avoid having to write the same boilerplate for every token in a rule.

### [raw](#raw)

When you want more control over the regular expression, you can use the `raw` key instead:

```yaml
extends: existence
message: "Incorrect use of symbols in '%s'."
ignorecase: true
raw:
  - $[d]* ?(?:dollars|usd|us dollars)
```

This allows you to write more complex patterns without having to worry about any post-processing. Each entry in `raw` is concatenated with the previous entry, allowing for improved commenting and readability of complex patterns.

### [message](#message)

The `message` key is a string that will be used to generate the final message when a match is found. The (optional) `%s` placeholder will be replaced with the matched text.

[Transform](/keys/transform.md) [substitution](/checks/substitution.md)


---

# Agent Instructions: Querying This Documentation

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

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.vale.sh/checks/existence.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.