## New Features
- App-server v2 now emits collaboration tool calls as item events in the turn stream, so clients can render agent coordination in real time. (#9213)
- Collaboration tools gained richer agent control: `spawn_agent` accepts an agent role preset, and `send_input` can optionally interrupt a running agent before delivering the message. (#9275, #9276)
- `/models` metadata now includes upgrade migration markdown so clients can display richer guidance when suggesting model upgrades. (#9219)
## Bug Fixes
- [revert] Linux sandboxing now falls back to Landlock-only restrictions when user namespaces are unavailable, and sets `no_new_privs` before applying sandbox rules. (#9250)
- `codex resume --last` now respects the current working directory, with `--all` as an explicit override. (#9245)
- Stdin prompt decoding now handles BOMs/UTF-16 and provides clearer errors for invalid encodings. (#9151)
## Changelog
Full Changelog: https://github.com/openai/codex/compare/rust-v0.84.0...rust-v0.85.0
- #9219 Add `migration_markdown` in `model_info` @aibrahim-oai
- #9250 fix: fallback to Landlock-only when user namespaces unavailable and set PR_SET_NO_NEW_PRIVS early @viyatb-oai
- #9213 feat: collab tools app-server event mapping @jif-oai
- #9275 feat: add agent roles to collab tools @jif-oai
- #9276 feat: add interrupt capabilities to `send_input` @jif-oai
- #9209 feat: basic tui for event emission @jif-oai
- #9245 Changed `codex resume --last` to honor the current cwd @etraut-openai
- #9207 Propagate MCP disabled reason @gt-oai
- #9151 fix(exec): improve stdin prompt decoding @liqiongyu
- #9300 revert: remove pre-Landlock bind mounts apply @viyatb-oai