Creating mods

Create a data-only pack from a matching template, make one small change, then validate it. Packs can add room variants, decorative rooms, wallpapers and maps. They cannot supply runtime scripts.

First pack

1. Open Mods → Create on the title screen. Enter a title and description and choose Store, Restaurant, Residential, Office, Decor, Wallpaper or Map.
2. Select Create mod, then Open mods folder in the Edit step. The game copies the chosen template into the local mods directory.
3. Edit the copied pack. Start with one supported value or artwork change and keep the generated pack ID stable. See Manifest and Room definitions for the exact format.
4. Select the pack in Mods → Publish and choose Validate. Fix the reported errors.
5. Enable the pack, restart the game and check the changed content in a small tower or map before relying on it in an existing save.

See Artwork and translations and Wallpaper artwork for dimensions and frame mappings. Use the template matching the inherited room behaviour.

Create a map

Mods → Create → Map supplies a playable harbor template inside the game. Edit its data using the map reference.

The visual Map Mod Kit is included in the project's source checkout at tools/map-mod-kit. Source-project users can copy that folder into their own working folder and import its project.godot in Godot 4.7. Open map.tscn and use Export Map Mod to produce the installable data pack. If the export command is absent, enable Map Mod Export under Project → Project Settings → Plugins, as the kit's README describes.

This wiki currently provides no separate kit download. Players with only the game can start with the built-in Map template; obtaining the visual kit requires access to the source-project folder. The editor project and its exported pack are separate artifacts.

Preserve save compatibility

Keep published pack and content IDs stable. Saves require the recorded save_compatibility_version, default 1, to match and all referenced content IDs to remain available. Change the compatibility version when breaking the saved-content contract; changing the release version string alone does not make a breaking update compatible. See Enable, publish and save.

Publish through Workshop

With Steam running, validate the local pack in Mods → Publish and use Upload to Steam Workshop. New items begin private. Open View on Workshop to review the item before choosing its visibility. Keep the Workshop sidecar file beside the pack folder to update the same item later. Use a square preview around 512 × 512 pixels and under 1 MB.

For installation steps, see Using mods. For all supported fields and restrictions, see Modding.