diff --git a/backend/internal/service/openai_tool_corrector.go b/backend/internal/service/openai_tool_corrector.go
index 6dad1a75..9c9eab84 100644
--- a/backend/internal/service/openai_tool_corrector.go
+++ b/backend/internal/service/openai_tool_corrector.go
@@ -29,16 +29,16 @@ var codexToolNameMapping = map[string]string{
 	"execBash":     "bash",
 }
 
-// ToolCorrectionStats 记录工具修正的统计信息
+// ToolCorrectionStats 记录工具修正的统计信息（导出用于 JSON 序列化）
 type ToolCorrectionStats struct {
 	TotalCorrected    int            `json:"total_corrected"`
 	CorrectionsByTool map[string]int `json:"corrections_by_tool"`
-	mu                sync.RWMutex
 }
 
 // CodexToolCorrector 处理 Codex 工具调用的自动修正
 type CodexToolCorrector struct {
 	stats ToolCorrectionStats
+	mu    sync.RWMutex
 }
 
 // NewCodexToolCorrector 创建新的工具修正器
@@ -251,8 +251,8 @@ func (c *CodexToolCorrector) correctToolParameters(toolName string, functionCall
 
 // recordCorrection 记录一次工具名称修正
 func (c *CodexToolCorrector) recordCorrection(from, to string) {
-	c.stats.mu.Lock()
-	defer c.stats.mu.Unlock()
+	c.mu.Lock()
+	defer c.mu.Unlock()
 
 	c.stats.TotalCorrected++
 	key := fmt.Sprintf("%s->%s", from, to)
@@ -264,8 +264,8 @@ func (c *CodexToolCorrector) recordCorrection(from, to string) {
 
 // GetStats 获取工具修正统计信息
 func (c *CodexToolCorrector) GetStats() ToolCorrectionStats {
-	c.stats.mu.RLock()
-	defer c.stats.mu.RUnlock()
+	c.mu.RLock()
+	defer c.mu.RUnlock()
 
 	// 返回副本以避免并发问题
 	statsCopy := ToolCorrectionStats{
@@ -281,8 +281,8 @@ func (c *CodexToolCorrector) GetStats() ToolCorrectionStats {
 
 // ResetStats 重置统计信息
 func (c *CodexToolCorrector) ResetStats() {
-	c.stats.mu.Lock()
-	defer c.stats.mu.Unlock()
+	c.mu.Lock()
+	defer c.mu.Unlock()
 
 	c.stats.TotalCorrected = 0
 	c.stats.CorrectionsByTool = make(map[string]int)
diff --git a/backend/internal/service/openai_tool_corrector_test.go b/backend/internal/service/openai_tool_corrector_test.go
index 7219c2af..a1c4530a 100644
--- a/backend/internal/service/openai_tool_corrector_test.go
+++ b/backend/internal/service/openai_tool_corrector_test.go
@@ -38,8 +38,18 @@ func TestCorrectToolCallsInSSEData(t *testing.T) {
 				if err := json.Unmarshal([]byte(result), &payload); err != nil {
 					t.Fatalf("Failed to parse result: %v", err)
 				}
-				toolCalls := payload["tool_calls"].([]any)
-				functionCall := toolCalls[0].(map[string]any)["function"].(map[string]any)
+				toolCalls, ok := payload["tool_calls"].([]any)
+				if !ok || len(toolCalls) == 0 {
+					t.Fatal("No tool_calls found in result")
+				}
+				toolCall, ok := toolCalls[0].(map[string]any)
+				if !ok {
+					t.Fatal("Invalid tool_call format")
+				}
+				functionCall, ok := toolCall["function"].(map[string]any)
+				if !ok {
+					t.Fatal("Invalid function format")
+				}
 				if functionCall["name"] != "edit" {
 					t.Errorf("Expected tool name 'edit', got '%v'", functionCall["name"])
 				}
@@ -54,7 +64,10 @@ func TestCorrectToolCallsInSSEData(t *testing.T) {
 				if err := json.Unmarshal([]byte(result), &payload); err != nil {
 					t.Fatalf("Failed to parse result: %v", err)
 				}
-				functionCall := payload["function_call"].(map[string]any)
+				functionCall, ok := payload["function_call"].(map[string]any)
+				if !ok {
+					t.Fatal("Invalid function_call format")
+				}
 				if functionCall["name"] != "todowrite" {
 					t.Errorf("Expected tool name 'todowrite', got '%v'", functionCall["name"])
 				}
@@ -131,8 +144,18 @@ func TestCorrectToolCallsInSSEData(t *testing.T) {
 				if err := json.Unmarshal([]byte(result), &payload); err != nil {
 					t.Fatalf("Failed to parse result: %v", err)
 				}
-				toolCalls := payload["tool_calls"].([]any)
-				functionCall := toolCalls[0].(map[string]any)["function"].(map[string]any)
+				toolCalls, ok := payload["tool_calls"].([]any)
+				if !ok || len(toolCalls) == 0 {
+					t.Fatal("No tool_calls found in result")
+				}
+				toolCall, ok := toolCalls[0].(map[string]any)
+				if !ok {
+					t.Fatal("Invalid tool_call format")
+				}
+				functionCall, ok := toolCall["function"].(map[string]any)
+				if !ok {
+					t.Fatal("Invalid function format")
+				}
 				if functionCall["name"] != "edit" {
 					t.Errorf("Expected tool name 'edit', got '%v'", functionCall["name"])
 				}