Codex: subagents on a magpie model
Codex's spawn_agent tool only lists the first five models Codex knows, and when signed in to ChatGPT those are all OpenAI's — so a subagent never landed on a magpie model unless you named one outright.
Codex now has a subagents field (magpie codex subagent <provider/model>, or in the app next to effort). It sets [agents] default_subagent_model, the model a subagent starts on when none is asked for. It's offered once Codex itself runs through magpie, and it's removed again when Codex goes back to its own models. Other keys in your [agents] table are left as they are.
Restart Codex after changing it.