Function codex_config_path 

pub fn codex_config_path() -> PathBuf

Return the location of Codex’s user-level config.toml.

Honors $CODEX_HOME when set (Codex supports it for isolated installs), falling back to ~/.codex/config.toml. Matches the behaviour of the Codex CLI itself — see the sqlite_home discussion in Codex’s docs/config.md, which describes the same resolution order.