Error listing out comma-separated tags: Can't iterate over paramater

My frontmatter for individual posts is as follows:

title: "The Yellow Pages"
date: 2021-01-08T14:09:59+05:30
tools: 3D Software, Blender, Maya
description: This is a sample description.

In my post, I would like to display a list of tools that are associated with the post in the form of clickable links. I’ve gone through the posts on this forum and Stackoverflow on how to do this and this is what I am using:

{{ range $key, $value := }}
{{if ne $value "null"}}
<a href="/tools/{{ $value | urlize  }}">{{ $value }}</a></span>
{{ end }}

But I am getting this error:

Failed to render pages: render of "page" failed:
execute of template failed: template: _default/single.html:75:66: executing "main" at <>: 
range can't iterate over 3D Software, Blender, Maya

What is going wrong here?

tools: [ 3D Software, Blender, Maya ]