Expert-only Transitions
You can use Skillset fields along with Jira’s built-in Workflow Conditions to restrict transitions based on user’s competence. Only users who match the skill requirements included in a task will be allowed to execute the transition.
Configuring your Workflow
Open your Jira Workflow for editing
Select the Transition of interest
Configure workflow conditions as on the screenshot below:
“Any of the following conditions” should be true:
Add a standard workflow condition "User Is In Custom field"
Use the "Skillset field name-Experts" field as a target
“All of the following conditions” should be true (condition group)
“Skillset field name” is empty
“Skillset field name-Experts” is empty
Workflow conditions in the example are configured to restrict transitions to “In Progress” based on qualification, if skill requirements are specified. If not - anyone can work on the task.
You can get much more creative with "Skillset" fields and Jira workflows if you are using Jira addons that offer custom workflow extensions like Script Runner for Jira Cloud.
For example, you could prevent transitions if there's another user with the required skillset, who has better availability. You could do that by reading the users property of the "Skillset" field and analyzing backlog for all qualified users.