diff --git a/hermes_cli/kanban_db.py b/hermes_cli/kanban_db.py
index 7cee6feaf3c6..ed617c8634ab 100644
--- a/hermes_cli/kanban_db.py
+++ b/hermes_cli/kanban_db.py
@@ -8046,6 +8046,13 @@ def _default_spawn(
         "chat",
         "-q", prompt,
     ])
+    if task.goal_mode:
+        # Goal-mode workers must take the fully-quiet single-query path:
+        # the kanban goal-loop hook (_run_kanban_goal_loop_q) only runs in
+        # cli.py's quiet branch. Without -Q the worker gets exactly one
+        # turn, prints text, exits rc=0, and the dispatcher records a
+        # protocol violation (incident 2026-06-09 t_d9cbe312).
+        cmd.append("-Q")
     # Redirect output to a per-task log under <board-root>/logs/.
     # Anchored at the board root (not the shared kanban root), so
     # `hermes kanban log` on a specific board reads its own file and