Improved handling of config file errors

What variant of Codex are you using?

CLI, Extension

What feature would you like to see?

I propose a pro-active effort to have Codex report specific issues in specific files to the UI/client when such issues are found during processing. It seems at the moment that an exception might be ignored or simply not thrown/handled.

@Urkman reported in #9001 :

I found the problem with the help of Codex CLI 0.80. This version showed me an error a skill file. Codex in VS Code silently failed.

@etraut-openai responded https://github.com/openai/codex/issues/9001#issuecomment-3734975032 :

Codex should be more resilient here — or at least provide a better error message

If there is an issue with config.toml, a skill config,, or some other file being processed, Codex silently fails with the UI reacting in different ways. The UI should report these issues clearly for resolution. Maybe in a debug log with a debug flag set to avoid breaking changes with existing UI's?

This might be related to #11727, as for me those issues began at the same time as I found an invalid prop in config.toml. Fixing that error didn't address the other failures, but there might be another config error that leads to the other failures. Without helpful tooling, I simply can't know.

Additional information

_No response_