Drupal → Добавить своё действие над сущностью в contextual links

1. Регистрируем роут:

# modulename.routing.yml

entity.node.my_action:
  path: '/node/{node}/my-action'
  defaults:
    _form: '\Drupal\modulename\Form\MyActionForm'
    _title: 'My action'
  requirements:
    _permission: 'administer site configuration'
  options:
    _admin_route: TRUE

2. Создаём контроллер или форму:

<?php
// src/Form/MyAction.php

namespace Drupal\modulename\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\node\NodeInterface;

class MyActionForm extends FormBase {

  /**
   * {@inheritDoc}
   */
  public function getFormId(): string {
    return 'my_action_form';
  }

  /**
   * {@inheritDoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, NodeInterface $node = NULL): array {
    $form['actions'] = [
      '#type' => 'actions',
    ];

    $form['actions']['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Confirm'),
    ];

    return $form;
  }

  /**
   * {@inheritDoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state): void {
    $node = $form_state->getBuildInfo()['args'][0]; /** @var NodeInterface $node */
    ...
  }

}

3. Добавляем действие в ссылки:

# modulename.links.contextual.yml

entity.node.my_action:
  title: 'My action'
  route_name: 'entity.node.my_action'
  group: 'node'
  weight: 100