How to override Codex config values from the CLI

Command-line config overrides let you run Codex with one-off settings without touching shared configuration, keeping experiments and temporary tweaks isolated from routine runs.

The -c flag supplies configuration overrides as key=value pairs, including dotted keys for nested settings. Overrides apply only to the current codex invocation, and repeating -c lets you adjust multiple settings at once without editing /~/.codex/config.toml.

CLI overrides parse values as TOML, so quoting and bracket syntax matter when passing arrays, strings, or booleans. If a value cannot be parsed as TOML, Codex treats it as a literal string, so quote values that include spaces or shell-sensitive characters.

1. Run codex exec with a temporary model override.

   $ codex exec -c model="gpt-5.2-codex" "Return OK."
   OK

   String values are easiest to handle when quoted, even when the value looks simple.

   Related: How to fix Codex trusted directory errors

2. Add another override to change multiple settings for the same run.

   $ codex exec -c model="gpt-5.2-codex" -c 'sandbox_permissions=["disk-full-read-access"]' "Return OK."
   OK

   Array values must be valid TOML, so wrap lists in brackets and quote strings.

   Related: How to fix Codex trusted directory errors

3. Run the same prompt without overrides to return to the configured defaults.

   $ codex exec "Return OK."
   OK

   Omitting -c restores the default configuration for the next run.

4. Avoid passing secrets through -c overrides.

   Command-line arguments can be stored in shell history and may be visible in process listings, so sensitive values are safer in protected config storage or environment-based secret injection.