Looks open-source to me - https://github.com/openai/codex/tree/main/codex-rs
I would bet it took more wall-clock time to type out that comment than it would have for any number of AI agents to snap the required equivalent of `if not re.match(...): continue` into place
// TODO: Verify server name: require `^[a-zA-Z0-9_-]+$`?
There may be several elements of server name verification to perform.That regex does not cover the complete range of possibilities for a server name.
The author apparently decided to punt on the correctness of this low-risk test -- pending additional thought, research, consultation, or simply higher prioritization.
Reviewing the source for this tree, looks like it's been in public development for a fair amount of time, with many PRs.