diff --git a/backend/internal/session_manager/manager.go b/backend/internal/session_manager/manager.go
index 8bced2016..10b956070 100644
--- a/backend/internal/session_manager/manager.go
+++ b/backend/internal/session_manager/manager.go
@@ -1023,10 +1023,10 @@ func (m *Manager) writeSystemPromptFile(id domain.SessionID, systemPrompt string
 		return "", nil
 	}
 	path := filepath.Join(m.dataDir, "prompts", string(id), "system.md")
-	if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
 		return "", err
 	}
-	if err := os.WriteFile(path, []byte(strings.TrimRight(systemPrompt, "\n")+"\n"), 0600); err != nil {
+	if err := os.WriteFile(path, []byte(strings.TrimRight(systemPrompt, "\n")+"\n"), 0o600); err != nil {
 		return "", err
 	}
 	return path, nil