# Issuable-like Rails models utilities GitLab Rails codebase contains several models that hold common functionality and behave similarly to [Issues](https://docs.gitlab.com/ee/user/project/issues/). Other examples of "issuables" are [Merge Requests](https://docs.gitlab.com/ee/user/project/merge_requests/) and [Epics](https://docs.gitlab.com/ee/user/group/epics/). This guide accumulates guidelines on working with such Rails models. ## Important text fields There are max length constraints for the most important text fields for `Issuable`s: - `title`: 255 chars - `title_html`: 800 chars - `description`: 1 megabyte - `description_html`: 5 megabytes