diff --git a/pkg/models/task_assignees.go b/pkg/models/task_assignees.go
index 6324c5223..517d9fc5d 100644
--- a/pkg/models/task_assignees.go
+++ b/pkg/models/task_assignees.go
@@ -346,7 +346,7 @@ func (la *TaskAssginee) ReadAll(s *xorm.Session, a web.Auth, search string, page
 // BulkAssignees is a helper struct used to update multiple assignees at once.
 type BulkAssignees struct {
 	// A project with all assignees
-	Assignees []*user.User `json:"assignees"`
+	Assignees []*user.User `json:"assignees" doc:"The full set of users to assign to the task. This replaces the task's current assignees: users not in this list are unassigned. Pass an empty array to unassign everyone. Each user must have access to the task's project."`
 	TaskID    int64        `json:"-" param:"projecttask"`
 
 	web.CRUDable    `json:"-"`