WordPress plugin: bootstrap (main file)

The single PHP file at the plugin root, named after the plugin folder, that WordPress loads first when the plugin is active. Get this right and the rest of the plugin can be a clean class-based architecture; get it wrong and you ship a plugin that fails activation, leaks runtime errors, or won't update cleanly.

This skill covers ONLY the entry-point file and the immediately-adjacent decisions (composer.json, optional uninstall.php reference). Activation cleanup, deactivation cron clear, custom uninstall logic — those are scope for wp-plugin-lifecycle (sibling skill).

When to use this skill

Trigger when ANY of the following is true:

• Scaffolding a new WordPress plugin from scratch.
• Reviewing the main plugin file in a PR — header, constants, autoload setup, activation hook.
• Migrating an old plugin to WP 6.5+ (Requires Plugins) or WP 6.7+ (i18n timing).
• Debugging activation errors: "Plugin could not be activated", "_doing_it_wrong" notices on __() / _e(), "Class not found" on first load.
• The plugin is shipping outside wp.org and needs a self-hosted updater.
• Adopting Composer / PSR-4 autoload in a plugin that previously didn't have it (or vice versa, removing the dependency).
• Migrating away from legacy includes/class-my-plugin-foo.php files toward src/Foo.php / src/Domain/FooService.php.

The diff or file most likely contains: a Plugin Name: header, register_activation_hook, register_deactivation_hook, spl_autoload_register, defined('ABSPATH'), plugins_loaded, Requires Plugins, or a composer.json at the plugin root.