Extension points

A whole platform

storeseeder_platforms is the entire surface needed. Append an object implementing Platform_Interface — extending Platform_Driver is shortest — and the generators, the REST API, the CLI and the admin all pick it up.

add_filter( 'storeseeder_platforms', function ( array $platforms ): array {
    $platforms[] = new My_Store_Driver();

    return $platforms;
} );

A driver declares which resources it supports and, when it refuses one, which kind of refusal it is:

Capability::unsupported( 'This platform records payment on the order.' );
Capability::missing_extension( 'my-subs', 'My Subscriptions' );
Capability::supported_except( array( 'company' ) );

supported_except() is for a canonical field the platform cannot store — not for one nothing implements, and not for one whose intent was met by other means. A false alarm is worse than the lost nuance.

A recipe

Two filters, and no download involved:

add_filter( 'storeseeder_recipes', function ( $manifests ) {
    $manifests[] = json_decode( file_get_contents( __DIR__ . '/my-recipe/recipe.json' ), true );

    return $manifests;
} );

add_filter( 'storeseeder_recipe_directories', function ( $dirs ) {
    $dirs['my-recipe'] = __DIR__ . '/my-recipe';

    return $dirs;
} );

Everything else

Filter	What it does
`storeseeder_capability`	One gate for the menu, REST, MCP and AJAX
`storeseeder_platform_writers_{id}`	Replace or add a writer for one driver
`storeseeder_platform_supports_{id}`	Override a driver’s capability matrix
`storeseeder_platform_fields_{id}`	Extra generation parameters only that driver understands
`storeseeder_platform_search_{id}`	What the entity pickers suggest
`storeseeder_platform_admin_url_{id}`	Where a resource lives in wp-admin
`storeseeder_canonical_{resource}`	Alter one entity before it is written
`storeseeder_canonical_entity`	The all-resources counterpart, running first
`storeseeder_before_write_{platform}_{resource}`	Act either side of a write
`storeseeder_target_platform`	Force the resolved target
`storeseeder_rest_controllers`	Register a controller
`storeseeder_cli_commands`	Register a WP-CLI command
`storeseeder_mcp_abilities`	Register an MCP ability
`storeseeder_mcp_ability_definition`	Amend one ability without replacing the class
`storeseeder_mcp_settings`	Override the three AI switches
`storeseeder_rest_params`	Alter every endpoint’s schema; runs before the per-endpoint filter
`storeseeder_locales`	The generatable locale list
`storeseeder_purge_order`	The order resources are deleted in
`storeseeder_admin_payload`	Add to what is inlined as `window.storeseederApi`
`storeseeder_sample_data_source`	Where the vocabulary archive comes from
`storeseeder_recipes_source`	Where the recipe archive comes from

Adding a resource

Six pieces, and a driver that declares support while shipping no writer is reported as storeseeder_missing_writer rather than failing once per item:

A generator extending Generation\Generator
A writer per driver, extending Platforms\Writer
That driver’s writer_classes() and capabilities()
The canonical name in Platforms\Resource
A controller extending Rest\Controller
Admin registration in src/lib/generators.ts