diff --git a/src/features/tmux-subagent/attachable-session-status.test.ts b/src/features/tmux-subagent/attachable-session-status.test.ts
new file mode 100644
index 000000000..6ff1ce9ad
--- /dev/null
+++ b/src/features/tmux-subagent/attachable-session-status.test.ts
@@ -0,0 +1,18 @@
+/// <reference types="bun-types" />
+
+import { describe, expect, test } from "bun:test"
+
+import { isAttachableSessionStatus } from "./attachable-session-status"
+
+describe("isAttachableSessionStatus", () => {
+  test("#given a busy session #when checking attachability #then it is attachable", () => {
+    //#given
+    const status = "busy"
+
+    //#when
+    const attachable = isAttachableSessionStatus(status)
+
+    //#then
+    expect(attachable).toBe(true)
+  })
+})
diff --git a/src/features/tmux-subagent/attachable-session-status.ts b/src/features/tmux-subagent/attachable-session-status.ts
index 22dc89770..f525e5e0a 100644
--- a/src/features/tmux-subagent/attachable-session-status.ts
+++ b/src/features/tmux-subagent/attachable-session-status.ts
@@ -1,4 +1,4 @@
-const ATTACHABLE_SESSION_STATUSES = ["idle", "running"] as const
+const ATTACHABLE_SESSION_STATUSES = ["idle", "running", "busy"] as const
 
 export type AttachableSessionStatus = (typeof ATTACHABLE_SESSION_STATUSES)[number]