Vouch request: ERA-Fathom

[ERA-Fathom]

What do you want to work on?

I want to fix two items in the multi-agent-notepad example. In the current release, the demo script uses a command combination that the CLI currently rejects. And the network policy doesn’t cover where npm installs Codex. The RFC 0009 points to the agent-traces-exporter example as an illustration of the supervisor middleware hook, but it isn’t shipped in the repository, so I would like to contribute that.

Why this change?

Anyone who follows the multi-agent-notepad README on the current release will hit an error at their first sandbox create. The script passes an upload and a command together. The CLI now refuses that combination, so the example doesn’t run as shipped. Even with that fixed, building an image the same way that codex-app-server Dockerfile does puts Codex under /usr/local. The example's policy only binds the /usr/bin and /usr/lib paths, so the platform denies Codex's own connections, and the demo fails again.

For the exporter, RFC 0009 uses agent-traces-exporter as the case that explains the supervisor middleware hook, so it is the first thing a reader will look for, and it doesn’t exist. Anyone who wants a record of what their agents did inside sandboxes has to write a middleware from the proto file on their own. A shipped fail-open example that records each request and response would give them a starting point and would exercise the hook on the platform's own multi-agent example.

Checklist

• I wrote this request myself (not AI-generated)
• I have read CONTRIBUTING.md