Mod manifest (manifest.json)

Every mod must include a manifest.json file in its root directory. The manifest defines mod metadata, dependencies, and loading behavior.

A JSON schema file (manifest.schema.json) is included in the ExampleMod project for IDE IntelliSense support.

Required fields

Field	Type	Description
`id`	string	Unique mod identifier. Must match `[a-zA-Z0-9][a-zA-Z0-9_-]*`. Must not start with `COI-` (reserved for official content).
`version`	string	Mod version (e.g. `0.0.1`, `1.2.3a`). Follows the pattern `major.minor[.patch[letter]]`.
`primary_dlls`	string[]	List of DLL file names to load (DLLs will be loaded in the provided order). All loaded DLLs must be located in the mod's directory.

Optional fields

Field	Type	Description
`display_name`	string	Human-readable name shown in UI (max 50 characters).
`description_short`	string	Short description (max 180 characters).
`description_long`	string	Detailed description shown in mod details.
`authors`	string or string[]	Author name or array of author names.
`min_game_version`	string	Minimum compatible game version (e.g. `0.8.0`).
`max_verified_game_version`	string	Highest game version the mod has been tested with.
`links`	string[]	Web links (GitHub, YouTube, etc.).
`mod_dependencies`	string[]	Required mod IDs. Supports version constraints (e.g. `OtherMod >= 1.0.0`).
`optional_mod_dependencies`	string[]	Optional mod IDs with same version constraint syntax.
`incompatible_mods`	string[]	Mod IDs that cannot be loaded together with this mod.
`non_locking_dll_load`	bool	If `true`, DLLs are loaded into memory instead of locked on disk. Allows updating files without closing the game.
`can_add_to_saved_game`	bool	If `true`, the mod can be added to an existing save.
`can_remove_from_saved_game`	bool	If `true`, the mod can be removed from an existing save.
`primary_mod_class_name`	string	Class name to use when multiple `IMod` implementations are found in the loaded DLLs.

Example manifest

{
  "id": "ExampleMod",
  "version": "0.0.1",
  "display_name": "Example Mod",
  "description_short": "A simple example mod for Captain of Industry.",
  "authors": "Your Name",
  "primary_dlls": ["ExampleMod.dll"],
  "non_locking_dll_load": true
}

Dependencies

Mods are loaded in dependency order (topologically sorted). If your mod depends on another mod, declare it in mod_dependencies:

{
  "mod_dependencies": ["SomeLibraryMod", "AnotherMod >= 2.0.0"]
}

Dependencies with version constraints use the >= syntax (e.g. ModId >= 1.0.0). Spaces around >= are recommended for readability. All mandatory dependencies must be present and loaded, or the game will report an error. Optional dependencies (optional_mod_dependencies) are loaded first if available but do not cause errors if missing.