diff --git a/src/features/background-agent/manager.test.ts b/src/features/background-agent/manager.test.ts
index 1b45ccf4d..cef1ef935 100644
--- a/src/features/background-agent/manager.test.ts
+++ b/src/features/background-agent/manager.test.ts
@@ -875,6 +875,90 @@ describe("BackgroundManager.notifyParentSession - dynamic message lookup", () =>
   })
 })
 
+describe("BackgroundManager.notifyParentSession - aborted parent", () => {
+  test("should skip notification when parent session is aborted", async () => {
+    //#given
+    let promptCalled = false
+    const client = {
+      session: {
+        prompt: async () => {
+          promptCalled = true
+          return {}
+        },
+        abort: async () => ({}),
+        messages: async () => {
+          const error = new Error("User aborted")
+          error.name = "MessageAbortedError"
+          throw error
+        },
+      },
+    }
+    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput)
+    const task: BackgroundTask = {
+      id: "task-aborted-parent",
+      sessionID: "session-child",
+      parentSessionID: "session-parent",
+      parentMessageID: "msg-parent",
+      description: "task aborted parent",
+      prompt: "test",
+      agent: "explore",
+      status: "completed",
+      startedAt: new Date(),
+      completedAt: new Date(),
+    }
+    getPendingByParent(manager).set("session-parent", new Set([task.id, "task-remaining"]))
+
+    //#when
+    await (manager as unknown as { notifyParentSession: (task: BackgroundTask) => Promise<void> })
+      .notifyParentSession(task)
+
+    //#then
+    expect(promptCalled).toBe(false)
+
+    manager.shutdown()
+  })
+
+  test("should swallow aborted error from prompt", async () => {
+    //#given
+    let promptCalled = false
+    const client = {
+      session: {
+        prompt: async () => {
+          promptCalled = true
+          const error = new Error("User aborted")
+          error.name = "MessageAbortedError"
+          throw error
+        },
+        abort: async () => ({}),
+        messages: async () => ({ data: [] }),
+      },
+    }
+    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput)
+    const task: BackgroundTask = {
+      id: "task-aborted-prompt",
+      sessionID: "session-child",
+      parentSessionID: "session-parent",
+      parentMessageID: "msg-parent",
+      description: "task aborted prompt",
+      prompt: "test",
+      agent: "explore",
+      status: "completed",
+      startedAt: new Date(),
+      completedAt: new Date(),
+    }
+    getPendingByParent(manager).set("session-parent", new Set([task.id]))
+
+    //#when
+    await (manager as unknown as { notifyParentSession: (task: BackgroundTask) => Promise<void> })
+      .notifyParentSession(task)
+
+    //#then
+    expect(promptCalled).toBe(true)
+
+    manager.shutdown()
+  })
+})
+
 function buildNotificationPromptBody(
   task: BackgroundTask,
   currentMessage: CurrentMessage | null
diff --git a/src/features/background-agent/manager.ts b/src/features/background-agent/manager.ts
index 768b33383..0938a81b6 100644
--- a/src/features/background-agent/manager.ts
+++ b/src/features/background-agent/manager.ts
@@ -1123,7 +1123,14 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
           break
         }
       }
-    } catch {
+    } catch (error) {
+      if (this.isAbortedSessionError(error)) {
+        log("[background-agent] Parent session aborted, skipping notification:", {
+          taskId: task.id,
+          parentSessionID: task.parentSessionID,
+        })
+        return
+      }
       const messageDir = getMessageDir(task.parentSessionID)
       const currentMessage = messageDir ? findNearestMessageWithFields(messageDir) : null
       agent = currentMessage?.agent ?? task.parentAgent
@@ -1154,6 +1161,13 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
         noReply: !allComplete,
       })
     } catch (error) {
+      if (this.isAbortedSessionError(error)) {
+        log("[background-agent] Parent session aborted, skipping notification:", {
+          taskId: task.id,
+          parentSessionID: task.parentSessionID,
+        })
+        return
+      }
       log("[background-agent] Failed to send notification:", error)
     }
 
@@ -1192,6 +1206,28 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
     return `${seconds}s`
   }
 
+  private isAbortedSessionError(error: unknown): boolean {
+    const message = this.getErrorText(error)
+    return message.toLowerCase().includes("aborted")
+  }
+
+  private getErrorText(error: unknown): string {
+    if (!error) return ""
+    if (typeof error === "string") return error
+    if (error instanceof Error) {
+      return `${error.name}: ${error.message}`
+    }
+    if (typeof error === "object" && error !== null) {
+      if ("message" in error && typeof error.message === "string") {
+        return error.message
+      }
+      if ("name" in error && typeof error.name === "string") {
+        return error.name
+      }
+    }
+    return ""
+  }
+
   private hasRunningTasks(): boolean {
     for (const task of this.tasks.values()) {
       if (task.status === "running") return true