diff --git a/internal/adapter/openai/message_normalize_test.go b/internal/adapter/openai/message_normalize_test.go
index a4e1843..ecb3bbd 100644
--- a/internal/adapter/openai/message_normalize_test.go
+++ b/internal/adapter/openai/message_normalize_test.go
@@ -237,3 +237,23 @@ func TestNormalizeOpenAIMessagesForPrompt_DeveloperRoleMapsToSystem(t *testing.T
 		t.Fatalf("expected developer role converted to system, got %#v", normalized[0]["role"])
 	}
 }
+
+func TestNormalizeOpenAIMessagesForPrompt_AssistantArrayContentFallbackWhenTextEmpty(t *testing.T) {
+	raw := []any{
+		map[string]any{
+			"role": "assistant",
+			"content": []any{
+				map[string]any{"type": "text", "text": "", "content": "工具说明文本"},
+			},
+		},
+	}
+
+	normalized := normalizeOpenAIMessagesForPrompt(raw, "")
+	if len(normalized) != 1 {
+		t.Fatalf("expected one normalized message, got %d", len(normalized))
+	}
+	content, _ := normalized[0]["content"].(string)
+	if content != "工具说明文本" {
+		t.Fatalf("expected content fallback text preserved, got %q", content)
+	}
+}
diff --git a/internal/prompt/messages.go b/internal/prompt/messages.go
index 5e124b4..e86c391 100644
--- a/internal/prompt/messages.go
+++ b/internal/prompt/messages.go
@@ -67,11 +67,11 @@ func NormalizeContent(v any) string {
 			typeStr, _ := m["type"].(string)
 			typeStr = strings.ToLower(strings.TrimSpace(typeStr))
 			if typeStr == "text" || typeStr == "output_text" || typeStr == "input_text" {
-				if txt, ok := m["text"].(string); ok {
+				if txt, ok := m["text"].(string); ok && txt != "" {
 					parts = append(parts, txt)
 					continue
 				}
-				if txt, ok := m["content"].(string); ok {
+				if txt, ok := m["content"].(string); ok && txt != "" {
 					parts = append(parts, txt)
 				}
 			}
diff --git a/internal/prompt/messages_test.go b/internal/prompt/messages_test.go
index 0407552..9114d39 100644
--- a/internal/prompt/messages_test.go
+++ b/internal/prompt/messages_test.go
@@ -21,3 +21,12 @@ func TestMessagesPrepareNilContentNoNullLiteral(t *testing.T) {
 		t.Fatalf("expected no null literal output, got %q", got)
 	}
 }
+
+func TestNormalizeContentArrayFallsBackToContentWhenTextEmpty(t *testing.T) {
+	got := NormalizeContent([]any{
+		map[string]any{"type": "text", "text": "", "content": "from-content"},
+	})
+	if got != "from-content" {
+		t.Fatalf("expected fallback to content when text is empty, got %q", got)
+	}
+}