--- title: Configuration --- Mantle is configured in two places: PHP constants that must be defined before the plugin boots, and a settings option managed through the admin UI, the REST API, or WP-CLI. ## Constants `mantle.php` defines these constants at load time. Only the three guarded ones can be overridden from `wp-config.php`; the rest are fixed values the plugin uses internally. To override an overridable constant, define it in `wp-config.php` above the `require_once ABSPATH . 'wp-settings.php';` line: ## Settings All module settings live in a single serialised WordPress option named `mantle`. The schema is assembled at runtime: `Mantle\Model\Settings::get_settings_schema()` applies a filter that every module hooks into, so the schema always describes exactly the modules present on the site. Reading a setting merges saved values over schema defaults, and any saved key absent from the schema is discarded on read. That means removing a module makes its keys inert rather than corrupting the option. For the complete list of keys, see the [settings reference](../reference/settings.md). ### Reading and writing settings ## Migrations On every `init` (priority 100) Mantle compares the `version` setting with `MANTLE_PLUGIN_VERSION`. When the stored version is older, it runs its migrations and writes the new version back. It also ensures the AI chatbot conversations table exists; that check short-circuits on a single autoloaded option read when the schema is current. ## Next steps - [First run](first-run.md) — the setup wizard and enabling modules. - [Settings reference](../reference/settings.md) — every registered key.