diff --git a/backend/src/workspace-maintenance.ts b/backend/src/workspace-maintenance.ts
index 7de7a036..dbb06eb5 100644
--- a/backend/src/workspace-maintenance.ts
+++ b/backend/src/workspace-maintenance.ts
@@ -134,6 +134,10 @@ export async function runWorkspaceMaintenanceCli(
     const result = failureResult(command, (() => {
       try { return JSON.parse(io.stdin).workspaceId ?? ""; } catch { return ""; }
     })());
+    if (process.env.P2_CHILD_DEBUG === "1") {
+      const detail = String((error as Error).message ?? "").replace(/[\r\n]+/g, " ").slice(0, 2048);
+      result.warnings = detail.length > 0 ? [detail] : undefined;
+    }
     io.writeStdout(boundedJson(result));
     if (process.env.P2_CHILD_DEBUG === "1") {
       const detail = String((error as Error).message ?? "").replace(/[\r\n]+/g, " ").slice(0, 2048);