Gameplay Tags for Unity

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Overview

This package brings to Unity the concept of Gameplay Tags, inspired by Unreal Engine’s Gameplay Tag system.

Gameplay Tags are string-based identifiers organized in a hierarchical way. They provide a flexible and efficient way to describe, categorize, and query gameplay-related states and properties.

They are useful for:

• Marking abilities, states, effects, or interactions.
• Checking conditions without hard-coded references.
• Creating clean and scalable gameplay logic.

With this package, you can register, organize, and use tags directly in Unity projects with an API designed to feel natural in C#.

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Getting Started

Before you can use tags, you first need to create them. There are three main ways to register tags in your project:

1. JSON Files in Project Settings

Create a folder named ProjectSettings/GameplayTags. Every .json file inside this folder will be automatically scanned and its tags registered.

The format is a JSON object where each property is a tag. The value of that property is another object, which may optionally include metadata such as a developer-facing comment:

{
  "Damage.Fatal": {},
  "Damage.Miss": {
    "Comment": "Attack landed but did not cause damage"
  },
  "CrowdControl.Stunned": {
    "Comment": "Unit cannot act at all"
  }
}

👉 You can have multiple JSON files in this folder — there’s no limitation to just one.

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2. Creating Tags via the Editor

Tags can also be created directly in the Unity Editor. The editor will generate the corresponding JSON file automatically and insert the tag for you (creating the file if necessary).

[Placeholder — here goes the screenshot showing where to add tags in the Editor]

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3. Registering Tags with Assembly Attributes

The third option is to declare tags directly in your assembly using attributes:

[assembly: GameplayTag("Damage.Fatal")]
[assembly: GameplayTag("Damage.Miss")]
[assembly: GameplayTag("CrowdControl.Stunned")]

This approach is particularly useful when your code requires the existence of certain tags. It ensures that the tag is always registered alongside the code that depends on it.

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API

GameplayTag

A lightweight struct representing a gameplay tag. Strings are implicitly convertible to GameplayTag, so you can write "Damage.Fire" directly where a GameplayTag is expected.

Core Properties

• string Name → The full name of the tag (e.g., "Damage.Fire").
• bool IsValid → Whether the tag is valid (registered in the system).
• bool IsNone → Whether the tag is the special None tag.
• bool IsLeaf → Whether the tag has no children.
• GameplayTag None → A special value representing an empty or invalid tag.

Hierarchy Properties

• ParentTags → All parent tags of this tag, ordered from root to immediate parent.

  • Example: for "A.B.C", the parent tags are ["A", "A.B"].

• ChildTags → All direct child tags of this tag.

  • Example: if "A.B.C" has two children "A.B.C.D" and "A.B.C.E", they will appear here.

• HierarchyTags → The full hierarchy chain including this tag and all of its parents.

  • Example: for "A.B.C", the hierarchy tags are ["A", "A.B", "A.B.C"].

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GameplayTagManager

A static class responsible for managing all registered tags in the project.

• RequestTag(string name, bool logWarningIfNotFound = true) → Gets a GameplayTag by name (returns GameplayTag.None if not found).
• GetAllTags() → Returns all registered tags.
• HasBeenReloaded (property) → Indicates whether the tags have been reloaded at runtime.

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GameplayTagContainer

The main API for working with sets of tags. Provides methods to add, remove, query, and combine gameplay tags.

Managing Tags

• AddTag(tag) → Adds a tag to the container.
• RemoveTag(tag) → Removes a tag from the container.
• Clear() → Clears all tags.

Querying Tags

• HasTag(tag) → Checks if the container contains the given tag (directly or via hierarchy).
• HasAny(container) → Returns true if any tag from another container are present.
• HasAll(container) → Returns true if all tags from another container are present.
• HasAnyExact(container) → Like HasAny, but only matches tags explicitly added.
• HasAllExact(container) → Like HasAll, but only matches tags explicitly added.

Combining Containers

• Union(containerA, containerB) → Creates a new container with all unique tags from both.
• Intersection(containerA, containerB) → Creates a new container with only the tags present in both.

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GameplayTagCountContainer

A variation of GameplayTagContainer that also tracks how many times each tag has been added, with support for callbacks when counts change.

Additional API:

• GetTagCount(tag) → Returns the current count of the given tag.
• RegisterTagEventCallback(tag, GameplayTagEventType type, Action<GameplayTag,int> callback) → Registers a callback triggered when the tag count changes.
• RemoveTagEventCallback(tag, GameplayTagEventType type, Action<GameplayTag,int> callback) → Removes a previously registered callback.

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License

This project is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) License. See the LICENSE file for details.