Drush commands have the ability to specify the level of Drupal's bootstrap before being executed. Drupal has several bootstrap levels in which only specific parts of the system are loaded. By default, a command's bootstrap is at DRUSH_BOOTSTRAP_DRUPAL_LOGIN, which is at the same level as accessing Drupal over the Web.

Commands, depending on their purpose, can choose to avoid bootstrapping Drupal at all or only until the database system is loaded. Drush commands that are utilities, such as the Git release notes module, provide a Drush command that does not interact with Drupal. It specifies a bootstrap of DRUSH_BOOTSTRAP_DRUSH, as it only interacts with repositories to generate change logs based on Git tags and commits.