I was having problems running pocket-ic in sandboxes such as the one used by Claude, Codex. Especially when you run multiple pocket-ic instances for tests simultaneously. When in stdio mode, it wont hit network restrictions.
Noticed recently others were complaining about the same issue, so here is a vibecoded patch (mostly for inspiration) that gets it done:
https://github.com/Neutrinomic/ic/commits/feature/stdio-mode