Thank you for all the information! I could install agda (2.6.1.3) successfully. For record, I write what I did (following Martin's message): softwareupdate --install-rosetta arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)" arch -x86_64 /usr/local/bin/brew install agda -- Kenichi Asai