WordPress at a glance
filter is not described

term_search_min_chars filter-hook . WP 4.0.0

Filters the minimum number of characters required to fire a tag search via Ajax.

Usage

add_filter( 'term_search_min_chars', 'filter_function_name_2098', 10, 3 );
function filter_function_name_2098( $characters, $tax, $s ){
	// filter...

	return $characters;
}
$characters(int)
The minimum number of characters required.
Default: 2
$tax(WP_Taxonomy)
The taxonomy object.
$s(string)
The search term.

Where the hook is called

wp_ajax_ajax_tag_search()
wp-admin/includes/ajax-actions.php 141
$term_search_min_chars = (int) apply_filters( 'term_search_min_chars', 2, $tax, $s );

Where the hook is used (in WP core)

Does not used.