# spelling

Learn about the spelling extension point.

| Name           | Type     | Description                                                                                        |
| -------------- | -------- | -------------------------------------------------------------------------------------------------- |
| `custom`       | `bool`   | Turn off the default filters for acronyms, abbreviations, and numbers.                             |
| `filters`      | `array`  | An array of patterns to ignore during spell checking.                                              |
| `ignore`       | `string` | A relative path (from `StylesPath`) to a file consisting of one word per line to ignore.           |
| `dicpath`      | `string` | The location to look for `.dic` and `.aff` files. Can be absolute or relative to the `StylesPath`. |
| `dictionaries` | `array`  | An array of dictionaries to load.                                                                  |
| `append`       | `bool`   | Adds the array of dictionaries after the default Vale dictionary, instead of replacing it.         |

`spelling` implements spell checking based on Hunspell-compatible dictionaries.

```yaml
# Uses the built-in dictionary and filters.
extends: spelling
message: "Did you really mean '%s'?"
level: error
```

By default, `spelling` includes a custom, open-source [dictionary for American English](https://github.com/errata-ai/en_US-web).

## [Dictionaries](#dictionaries)

You may instead use the `dictionaries` key to list multiple custom dictionaries:

```yaml
extends: spelling
message: "'%s' is a typo!"
dictionaries:
  - en_US
  - en_medical
```

The `spelling` extension point will look for `en_US.{dic,aff}` and `en_medical.{dic,aff}` files in `<StylesPath>/config/dictionaries`.

You can also use the `DICPATH` environment variable or the `dicpath` key.

## [Filters](#filters)

Vale comes with a set of built-in filters, as described in the table below:

| Filter                    | Description                                         |
| ------------------------- | --------------------------------------------------- |
| `[A-Z]{1}[a-z]+[A-Z]+\w+` | Mixed-cased words (such as “MongoDB”).              |
| `[^a-zA-Z_']`             | Words containing non-word tokens (such as numbers). |
| `[A-Z]+$`                 | Upper-cased words.                                  |

You can also choose define you own filters either with or without the built-in ones enabled:

```yaml
extends: spelling
message: "Did you really mean '%s'?"
level: error
# This disables the built-in filters. If you omit this
# key or set it to false, custom filters (see below) are
# added on top of the built-in ones.
custom: true
# A "filter" is a regular expression specifying words
# to ignore during spell checking.
filters:
  # Ignore all words starting with 'py'.
  #
  # e.g., 'PyYAML'.
  - '[pP]y.*\b'
```

## [Ignore files](#ignore-files)

Ignore files are plain-text files that list words to be ignored during spell check (one case-insensitive entry per line). For example:

```
destructuring
transpiler
```

You can name these files anything you’d like and reference them relative to the active `<StylesPath>/config/ignore` directory.

```yaml
extends: spelling
message: "Did you really mean '%s'?"
level: error
ignore:
  - ignore1.txt
  - ignore2.txt
```

See [Vocabularies](/keys/vocabularies.md) for information on rule-agnostic terminology lists.

[metric](/checks/metric.md) [sequence](/checks/sequence.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/spelling.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.