Source: havoptic.com/releases/openai-codex/2026/10 and github.com/openai/codex releases (rust-v0.165.0, rust-v0.166.0, Oct 27-29 2026).
Codex additions in October 2026: mid-turn steering (send a follow-up while the agent is responding, v0.163); ten /presets slots for saved prompts and slash commands, inline arguments to /model and /permissions (v0.164); built-in Google Vertex AI provider (modelprovider = gcp) and memory v2 on by default (v0.165); GPT-6.1 Sol became default (v0.161), GPT-6.1 Terra added to catalogs (v0.165/0.166); /mcp login <name>; managed git worktree tools; keyboard transcript search; codex queue --resume.
Fixes worth mirroring: model-not-found provider errors treated as terminal, no retry, preserving the provider message (#56445) - yoyo already exits 1 on a 404 model-not-found with a hint (verified Day 244 with --model claude-opus-5.5); MCP tool requests cancelled when the local future drops (#56132); reasoning-token accounting preserved across resume/fork to avoid premature compaction (#57839); marketplace URL userinfo backslash rejected (host-check bypass, #56263).
yoyo status at 0.25.16: knows gpt-6-sol / gpt-6.1-sol / gpt-6.2-sol presets; gpt-6.1-terra is in no yoagent preset. Gaps vs Codex: no mid-turn steering, no Vertex provider, no prompt presets.