Comment Attribute for Unity Scripts. Add this attribute to top of first property in a class for a quick comment on Editor

CommentAttribute.cs

using System;
using UnityEngine;
using System.Collections;
[AttributeUsage(AttributeTargets.Field, AllowMultiple = true)]
public class CommentAttribute : PropertyAttribute
{
    /// <summary>
    ///   <para>The header text.</para>
    /// </summary>
    public readonly string comment;

    /// <summary>
    /// The height
    /// </summary>
    public readonly float height = 100f;

    /// <summary>
    /// Add a comment above some fields in the Inspector.
    /// </summary>
    /// <param name="comment">The header text.</param>
    public CommentAttribute(string comment)
    {
        this.comment = comment;
    }
    /// <summary>
    /// Initializes a new instance of the <see cref="CommentAttribute"/> class.
    /// </summary>
    /// <param name="comment">The comment.</param>
    /// <param name="height">The height.</param>
    public CommentAttribute(string comment, float height)
    {
        this.comment = comment;
        this.height = height;
    }
}

#if UNITY_EDITOR
using UnityEditor;
[CustomPropertyDrawer(typeof(CommentAttribute))]
public class CommentDrawer : DecoratorDrawer
{
    public override void OnGUI(Rect position)
    {
        position.height -= 2f;
        position = EditorGUI.IndentedRect(position);
        GUI.Box(position, string.Empty);
        var text = new GUIContent((attribute as CommentAttribute).comment);
        var style = EditorStyles.textArea;
        style.normal.textColor = Color.green;

        style.fontStyle = FontStyle.Bold;
        GUI.TextArea(position, text.text, style);
    }

    public override float GetHeight()
    {
        return (this.attribute as CommentAttribute).height;
    }
}
#endif