Allow users to disable inline ghost suggestions in Codex CLI

What variant of Codex are you using?

Codex CLI

What feature would you like to see?

Please add a user setting to disable inline ghost suggestions in the Codex CLI prompt.

This was previously requested in #10562, but the issue was closed due to insufficient upvotes. The suggestions can do more harm than good: they add visual noise, distract users while composing prompts, take up valuable space in constrained terminals, and can create extra friction for screen-reader users. For experienced users who do not need prompt examples, the suggestions provide little value while appearing repeatedly.

Codex should let users opt out through a documented config.toml setting or environment variable. The suggestions can remain enabled by default; users should simply have control over whether they are shown.

Additional information

Related issue: #10562