The Contentful Migration CLI is a framework that makes migrations easy and allows developers to script changes to their content model in a fine-grained way, making the development process with Contentful as easy as possible. It can be used to create migration scripts describing changes to a content model, run these scripts on a given Contentful space, and apply the migration to the specified space once validated and approved. The CLI performs sanity checks on migration files for syntax and consistency issues, displays error details if validation issues are detected, and applies the migration plan after validation. To use the CLI, developers need to install Node.js, set up environment variables such as Contentful management access token and HTTP proxy settings, and create a migration script describing changes to their content model. The CLI is still in its early stages and will expand to cover content transformation and integration with other tools in the near future.