Rewrite rule never matching

I need to add some rewrite rules for my site.
I need to link this friendly URL:

www.example.com/site-tool-calendar

to

www.example.com/site-tool?tool=calendar

/site-tool is already a permalink inside WordPress and it is working

I have added the following on my functions.php

function custom_rewrite( $wp_rewrite ) {
    $feed_rules = array(
        '^site-tools-(^/.]+)/$'  =>  'site-tools/?tool=" . $wp_rewrite->preg_index(1),
    );
    $wp_rewrite->rules = $feed_rules + $wp_rewrite->rules;
}

add_filter( "generate_rewrite_rules', 'custom_rewrite' );

Before that, on the functions.php I added the param “tool” to the query vars:

function wpd_query_vars( $query_vars ){
    $query_vars[] = 'tool';
    return $query_vars;
}
add_filter('query_vars', 'wpd_query_vars');

I flushed the rules from the admin Permalink page, and tried to test the URL, but although my rule is being added inside the $wp_rewrite->wp_rewrite_rules() list, it is never matching.

It always match a generic rule that looks like:

([^/]+)(?:/([0-9]+))?/?$

I debugged it and checked that my rule appears at the rules list, at the beginning, but is never executed.

Can anyone help me to double check if I made something wrong? I have tried lot of alternatives and all of them took me to the same situation: the rule appears but is never executed.

Please try this.

First add the rewrite rule you need with this function

add_action( 'init', 'rewrite_site_tools_page' );
function rewrite_site_tools_page() {

  add_rewrite_rule(
    '^site-tools-([^/]+)$',
    'index.php?pagename=site-tools&tool=$matches[1]',
    'top');

}

Assuming that page name is site-tools.

Now add the tool as query var

add_filter('query_vars', 'wpd_query_vars');
function wpd_query_vars( $query_vars ){
    $query_vars[] = 'tool';
    return $query_vars;
}

Save permalinks.

Now if you access hxxp://yourdomain.com/site-tools-calculator/ It should work (calculator can be anything else )

If you want to debug it, you can dump the query var “tool” by this function:

add_action('template_redirect', 'test_my_queryvar', 999 );
function test_my_queryvar() {
    die( var_dump( get_query_var( 'tool' ) ) );
}