[V4] GraphQL type definitions are not generated

Hello!

It’s totally possible using the strapi.plugin('graphql').service('extension'), you have an example in the user and permission plugin:

  1. https://github.com/strapi/strapi/blob/master/packages/plugins/users-permissions/server/register.js#L8-L10
  2. https://github.com/strapi/strapi/blob/master/packages/plugins/users-permissions/server/graphql/index.js#L10

Here is the related documentation: GraphQL - Strapi Developer Docs

But before getting deeper with GraphQL I recommend you to check this post before: Discussion regarding the complex response structure for REST & GraphQL (Developer Experience)

Hope this help!