Codex 0.165.0 ships as a package tree and runs bin/codex-code-mode-host, codex-path/ and codex-resources/ relative to itself. The installer verified the full archive but kept only bin/codex, so code mode failed. Keep the whole verified tree, link ~/.local/bin/codex to its bin/codex, and replace the receipted flat install earlier runs left behind once the new tree verifies.