[[painless-field-context]]
=== Field context

Use a Painless script to create a
{es_version}/search-request-script-fields.html[script field] to return
a customized value for each document in the results of a query.

*Variables*

`params` (`Map`, read-only)::
        User-defined parameters passed in as part of the query.

`doc` (`Map`, read-only)::
        Contains the fields of the specified document where each field is a
        `List` of values.

{es_version}/mapping-source-field.html[`ctx['_source']`] (`Map`)::
        Contains extracted JSON in a `Map` and `List` structure for the fields
        existing in a stored document.

`_score` (`double` read-only)::
        The original score of the specified document.

*Return*

`Object`::
        The customized value for each document.

*API*

The standard <<painless-api-reference, Painless API>> is available.