diff --git a/hub-config/tasks.json b/hub-config/tasks.json
index a87b282..398a1c7 100644
--- a/hub-config/tasks.json
+++ b/hub-config/tasks.json
@@ -41,6 +41,7 @@
                             "output_type_id_params": {
                                 "is_required": true,
                                 "type": "character",
+                                "max_length": 3,
                                 "min_samples_per_task": 1,
                                 "max_samples_per_task": 100,
                                 "compound_taskid_set": ["round_id", "scenario_id", "target", "location", "pop_group"]