vcmi/docs/modders/Entities_Format/Secondary_Skill_Format.md

Main format

{
	"skillName":
	{
		//Mandatory, localizable skill name
		"name":     "Localizable name",

		// Optional base format, will be merged with basic/advanced/expert
		"base":     {Skill level base format},

		// Configuration for different skill levels
		"basic":    {Skill level format},
		"advanced": {Skill level format},
		"expert":   {Skill level format},
		
		// Chance for the skill to be offered on level-up (heroClass may override)
		"gainChance" : {
			// Chance for hero classes with might affinity
			"might" : 4,
			// Chance for hero classes with magic affinity
			"magic" : 6,
			// Chance for specific classes
			"knight" : 2,
			"cleric" : 8,
			...
		},
		
		// This skill is major obligatory (like H3 Wisdom) and is guaranteed to be offered once per specific number of levels
		"obligatoryMajor" : false,
		
		// This skill is minor obligatory (like H3 Magic school) and is guaranteed to be offered once per specific number of levels
		"obligatoryMinor" : false,
	}
}

Skill level base format

Json object with data common for all levels can be put here. These configuration parameters will be default for all levels. All mandatory level fields become optional if they equal "base" configuration.

Skill level format

{
	// Localizable description
	// Use {xxx} for formatting
	"description": "",

	// Bonuses provided by skill at given level
	// If different levels provide same bonus with different val, only the highest applies
	"effects":
	{
		"firstEffect":  {bonus format},
		"secondEffect": {bonus format}
		//...
	},
	
	// Skill icons of varying size
	"images" : {
		// 32x32 skill icon
		"small" : "",
		// 44x44 skill icon
		"medium" : "",
		// 82x93 skill icon
		"large" : "",
	}
}

Example

The following modifies the tactics skill to grant an additional speed boost at advanced and expert levels.

"core:tactics" : {
	"base" : {
		"effects" : {
			"main" : {
				"subtype" : "skill.tactics",
				"type" : "SECONDARY_SKILL_PREMY",
				"valueType" : "BASE_NUMBER"
			},
			"xtra" : {
				"type" : "STACKS_SPEED",
				"valueType" : "BASE_NUMBER"
			}
		}
	},
	"basic" : {
		"effects" : {
			"main" : { "val" : 3 },
			"xtra" : { "val" : 0 }
		}
	},
	"advanced" : {
		"description" : "{Advanced Tactics}\n\nAllows you to rearrange troups within 5 hex rows, and increases their speed by 1.",
		"effects" : {
			"main" : { "val" : 5 },
			"xtra" : { "val" : 1 }
		}
	},
	"expert" : {
		"description" : "{Expert Tactics}\n\nAllows you to rearrange troups within 7 hex rows, and increases their speed by 2.",
		"effects" : {
			"main" : { "val" : 7 },
			"xtra" : { "val" : 2 }
		}
	}
}