added test

main_test.go

@@ -1161,9 +1161,23 @@ func TestALRunSubagent(t *testing.T) {
 }
 
 func TestALSubagentDepthLimit(t *testing.T) {
-  // depth >= MAX_DEPTH must not spawn an HTTP request at all
+  // depth >= MAX_DEPTH must not spawn a child request; the LLM gets the
+  // depth-limit tool result and is expected to acknowledge and finish.
+  var n int
+  var mu sync.Mutex
   srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+    mu.Lock()
+    n++
+    cur := n
+    mu.Unlock()
+    switch cur {
+    case 1:
       w.Write([]byte(`{"choices":[{"message":{"role":"assistant","content":null,"tool_calls":[{"id":"c1","type":"function","function":{"name":"run_subagent","arguments":"{\"prompt\":\"deep\"}"}}]}}]}`))
+    case 2:
+      w.Write([]byte(`{"choices":[{"message":{"role":"assistant","content":"done"}}]}`))
+    default:
+      t.Errorf("unexpected request #%d (child must not be spawned)", cur)
+    }
   }))
   defer srv.Close()
 
@@ -1175,6 +1189,12 @@ func TestALSubagentDepthLimit(t *testing.T) {
   if err != nil {
     t.Fatalf("AL: %v", err)
   }
+  if n != 2 {
+    t.Errorf("expected exactly 2 LLM requests, got %d", n)
+  }
+  if got := last(msgs); got != "done" {
+    t.Errorf("last = %q, want done", got)
+  }
   found := false
   for _, m := range msgs {
     if m.Role == "tool" && m.Content != nil && strings.Contains(*m.Content, "depth limit") {