diff --git a/packages/opencode/src/tool/task.ts b/packages/opencode/src/tool/task.ts
index 94fca0e99d15..605aea7a7333 100644
--- a/packages/opencode/src/tool/task.ts
+++ b/packages/opencode/src/tool/task.ts
@@ -386,7 +386,10 @@ export const TaskTool = Tool.define(
           }),
         (_, exit) =>
           Effect.gen(function* () {
-            if (Exit.hasInterrupts(exit))
+            // Cancel on any abnormal exit (interrupt, fail, or die). Limiting cleanup to
+            // interrupts left subagent sessions orphaned when Effect.orDie converted tool
+            // errors into defects, so the parent continued while the child kept running.
+            if (Exit.isFailure(exit))
               yield* Effect.all([cancel, background.cancel(nextSession.id)], { discard: true })
           }).pipe(
             Effect.ensuring(