diff --git a/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java b/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
index 5aa9530..e451b31 100644
--- a/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
+++ b/fleetd/src/main/java/dev/ltms/fleet/rest/FleetApp.java
@@ -640,19 +640,25 @@ public final class FleetApp {
             }
             default -> ctx.status(202).json(Map.of(
                     "sessionId", id,
+                    // fleetd #571 (ticket comment 17126): no `default` here on purpose. This switch
+                    // is an expression, so the compiler already demands every Outcome constant have
+                    // an arm — adding an 11th constant to Outcome is a compile error here, not a
+                    // silent fall-through. That is exactly the bug this ticket exists to fix:
+                    // `default -> "done"` used to sit here and would have told a REST caller the
+                    // delegation completed for TIMED_OUT_UNCONFIRMED, the one outcome where delivery
+                    // is unknown. REPLIED, COMPLETED_UNREPLIED, QUESTION and STALE_TURN can never
+                    // actually reach this inner switch — the outer switch above always dispatches
+                    // them first — but they still need an arm to keep this switch exhaustive.
                     "status", switch (reply.outcome()) {
                         case TIMED_OUT_WORKING -> "working";
                         case TIMED_OUT_QUEUED -> "queued";
-                        // fleetd #571: delivery here is unknown, not merely still queued — see
-                        // Outcome#TIMED_OUT_UNCONFIRMED. Give it its own status rather than let it
-                        // fall to the default below, which would report "done" (delegation
-                        // completed) for the one case where we do not know whether it even arrived.
+                        // Delivery here is unknown, not merely still queued — see
+                        // Outcome#TIMED_OUT_UNCONFIRMED's own javadoc.
                         case TIMED_OUT_UNCONFIRMED -> "unconfirmed";
                         case BUSY -> "busy";
                         case WORKER_FAILED -> "failed";
                         case BACKEND_EXHAUSTED -> "backend_exhausted";
-                        default -> "done"; // unreachable — every non-terminal outcome reaching this
-                                            // switch (all six above) has its own explicit case
+                        case REPLIED, COMPLETED_UNREPLIED, QUESTION, STALE_TURN -> "done"; // unreachable
                     },
                     "detail", reply.outcome() == MessageService.Outcome.TIMED_OUT_UNCONFIRMED
                             ? "no reply within " + timeout + "ms; delivery is unconfirmed — the "