Let only the right person fill in a section

The reviewer of a task fills in the review section, and only while the work is in review.

This is the question teams keeping quality records ask most often: a task has fields anyone can fill in, but some fields should be filled by one specific person, and only at one specific stage. "Let the reviewer of this piece of work write the review result, and lock it once the work leaves In review." This scenario wires four settings together.

What you will get

A collapsible "Review" section on the task form
Only that task’s Reviewer can fill it in; anyone else is rejected on the server
The section is open only while the work is "In review", locked before and after
When work moves into In review the task is assigned to the reviewer automatically and they get notified

Steps

1Under Board settings > Custom fields, create a Person field: "Reviewer". In its settings turn ON "the person here watches the task", so the reviewer also receives status and due-date notifications.
2On the same screen create the fields that hold the outcome: for example "Review decision" (Select: Pass, Conditional, Fail) and "Review note" (multi-line Text).
3On the Field groups tab create a group called "Review" and move both fields into it.
4Set the group’s "who fills this in" rule to "the person named in a field" and pick the "Reviewer" field.
5Add a status condition to the same rule: "In review". The condition is added rather than replacing, so the rule now reads "the reviewer AND while the work is In review".
6Under Board settings > Workflow open the "In review" status and set its auto-assignment rule to "assign to a person field > Reviewer".
7Optionally, on the same screen put a role or person requirement on the transition leaving "In review", so only the reviewer can move the work on.

A board admin is NOT exempt from this rule, deliberately. If they were, the rule would mean "closed to everyone except admins" and would blur the question of who filled in a quality record. An admin’s route is to change the rule rather than bypass it, and that change lands in the audit log.

The rule is enforced on the server. The lock in the interface is not decoration: a request from someone without access is rejected through the API and through bulk import as well. The person expected to fill in a section is shown in its heading, so "is this waiting on me" is answered on screen.