Unity Skill Create

What it does

When your agent uses it

• Tasks that involve MCP servers
• Tasks that involve Schema markup
• Tasks that involve Game development

Example prompts

• “/unity-skill-create”

Requirements

• Node.js

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Accept a [RequestID] string? requestId parameter.
2. 2Return ResponseCallTool.Processing("...").SetRequestID(requestId) immediately.
3. 3Schedule the actual work asynchronously via MainThread.Instance.RunAsync(async () => { await Task.Yield(); ... }).
4. 4When the operation finishes, send the final result by calling

What it can do on your machine

Read from SKILL.md and the folder at commit 4c8056f. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • npm
  • npx

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use npm and npx, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Unity Skill Create loads about 2.1k tokens when it runs. Until then it costs about 160 tokens; SKILL.md has 588 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~160

When it runs · the whole SKILL.md, loaded when a task matches

~2.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from IvanMurzak/Unity-MCP at commit 4c8056f, republished under its Apache-2.0 licence (© IvanMurzak). 588 words, ~2,147 tokens.

name

unity-skill-create

description

Create a new skill (MCP tool) for the Unity Editor by writing a C# (.cs) file that Unity compiles into the project. After compilation the new tool becomes callable through MCP. The file must be a partial class decorated with [AiToolType], each tool method must be decorated with [AiTool], the class name should match the file name, all Unity API calls must run via com.IvanMurzak.ReflectorNet.Utils.MainThread.Instance.Run(), and the method should either return a structured data model (for parseable output) or void (for side-effect-only operations). See the body of this skill for a full sample and best-practice notes.

#nullable enable
using System;
using System.ComponentModel;
using com.IvanMurzak.McpPlugin;
using com.IvanMurzak.ReflectorNet.Utils;
using com.IvanMurzak.Unity.MCP.Editor.Utils;
using AIGD;
using UnityEditor;
using UnityEngine;

namespace com.IvanMurzak.Unity.MCP.Editor.API
{
    [AiToolType]
    public partial class Tool_Sample
    {
        [AiTool("sample-get", Title = "Sample / Get")]
        [Description("Finds a GameObject and returns its ref data.")]
        public GameObjectRef Get
        (
            [Description("Name of the GameObject to find.")]
            string name
        )
        {
            return MainThread.Instance.Run(() =>
            {
                var go = GameObject.Find(name)
                    ?? throw new ArgumentException($"GameObject '{name}' not found.", nameof(name));

                return new GameObjectRef(go);
            });
        }

        [AiTool("sample-rename", Title = "Sample / Rename")]
        [Description("Renames a GameObject.")]
        public void Rename
        (
            [Description("Current name of the GameObject.")]
            string name,
            [Description("New name to assign.")]
            string newName
        )
        {
            MainThread.Instance.Run(() =>
            {
                var go = GameObject.Find(name)
                    ?? throw new ArgumentException($"GameObject '{name}' not found.", nameof(name));

                go.name = newName;
                EditorUtility.SetDirty(go);
                AssetDatabase.Refresh(ImportAssetOptions.ForceSynchronousImport);
                EditorUtils.RepaintAllEditorWindows();
            });
        }
    }
}

AssetDatabase.Refresh(ImportAssetOptions.ForceSynchronousImport);
EditorUtils.RepaintAllEditorWindows();

MainThread.Instance.Run(() =>
{
    AssetDatabase.Refresh(ImportAssetOptions.ForceSynchronousImport);
});

_ = UnityMcpPluginEditor.NotifyToolRequestCompleted(new RequestToolCompletedData
{
    RequestId = requestId,
    Result = ResponseCallTool.Success("Operation completed.").SetRequestID(requestId)
});

// Tool file (Tool/MyTool.cs) - references the data model from AIGD:
using AIGD;

namespace com.IvanMurzak.Unity.MCP.Editor.API
{
    [AiToolType]
    public partial class Tool_Sample
    {
        public ResponseCallValueTool<MyResult> MyTool(...)
        {
            return ResponseCallValueTool<MyResult>.Success(new MyResult
            {
                Name = go.name,
                InstanceID = go.GetInstanceID()
            }).SetRequestID(requestId);
        }
    }
}

// Data model (Tool/Data/MyResult.cs) - top-level, in AIGD namespace, NOT nested:
namespace AIGD
{
    public class MyResult
    {
        [Description("Name of the GameObject.")]
        public string? Name { get; set; }

        [Description("Unity instance ID of the GameObject.")]
        public int InstanceID { get; set; }
    }
}

if (string.IsNullOrEmpty(name))
    throw new ArgumentException("Name cannot be null or empty.", nameof(name));

unity-mcp-cli run-system-tool unity-skill-create --input '{
  "path": "string_value",
  "code": "string_value"
}'

{
  "type": "object",
  "properties": {
    "path": {
      "type": "string"
    },
    "code": {
      "type": "string"
    }
  },
  "required": [
    "path",
    "code"
  ]
}

© IvanMurzak, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in Unity-MCP-Plugin/.claude/skills/unity-skill-create of IvanMurzak/Unity-MCP.

Open the folder on GitHubat commit 4c8056f