Codex: rust-v0.40.0 Release

Notable Changes

• Default model is now gpt-5-codex (#4076)
• Autocompaction is triggered automatically for gpt-5-codex when hitting 220k tokens (#4093)
• Usage limits are now visible in /status (#4053)
• New /review commands (review specific commit, against a base branch, or custom instructions) (#3961)
• The default timeout for MCP tool calls is 60s and can be overridden in config.toml by setting tool_timeout_sec for an individual MCP server. (#3959)

Merged PRs

• [#3881] fix: update try_parse_word_only_commands_sequence() to return commands in order (#3881)
• [#3814] Use a unified shell tell to not break cache (#3814)
• [#3878] Move responses mocking helpers to a shared lib (#3878)
• [#3888] Use helpers instead of fixtures (#3888)
• [#3937] fix alignment in slash command popup (#3937)
• [#3925] don't clear screen on startup (#3925)
• [#3950] Cache keyboard enhancement detection before event streams (#3950)
• [#3965] Forward Rate limits to the UI (#3965)
• [#3977] Tui: Rate limits (#3977)
• [#3961] feat: Add more /review options (#3961)
• [#3880] Add non_sandbox_test helper (#3880)
• [#4044] chore: unify cargo versions (#4044)
• [#4057] chore: more clippy rules 2 (#4057)
• [#3959] timeouts for mcp tool calls (#3959)
• [#4053] Add limits to /status (#4053)
• [#3928] simplify StreamController (#3928)
• [#4020] Tui: fix backtracking (#4020)
• [#4055] Remove /limits after moving to /status (#4055)
• [#4026] feat: Add view stack to BottomPane (#4026)
• [#4059] Change limits warning copy (#4059)
• [#4058] chore: clippy on redundant closure (#4058)
• [#4061] Fix branch mode prompt for /review (#4061)
• [#4060] Change headers and struct of rate limits (#4060)
• [#3952] Fix pager overlay clear between pages (#3952)
• [#3957] fix codex resume message at end of session (#3957)
• [#4068] Truncate potentially long user messages in compact message. (#4068)
• [#4076] feat: update default (#4076)
• [#4064] Add notifier tests (#4064)
• [#4093] chore: enable auto-compaction for gpt-5-codex (#4093)
• [#4096] Use TestCodex builder in stream retry tests (#4096)
• [#3914] feat: git tooling for undo (#3914)
• [#4082] fix: usage data tweaks (#4082)
• [#4075] Rate limits warning (#4075)