This week in Claude Code, Codex and Gemini CLI (week of October 18, 2026)

Originally published at https://aicoding-guide.com.

The change with the widest reach this week is idle compaction in Claude Code. Leave a long conversation sitting and it now gets summarised on its own.

On the Codex side, Daybreak is enabled by default again — a setting that only became an explicit opt-in five days earlier in v0.161.0. It has flipped twice in under a week.

Key point
This week in brief

• Claude Code compacts idle conversations automatically (idleCompaction turns it off)
• Codex 0.163.0 made Daybreak the default for eligible accounts again
• CLAUDE_CODE_DISABLE_FILE_MENTIONS and CLAUDE_CODE_AUTO_MODE_MODEL were added

Claude Code

Four releases this week, 2.1.299 through 2.1.302.

Idle compaction arrived (2.1.299, 2.1.302)

The CHANGELOG wording is: "Added idle compaction in the terminal: a 200K+ token conversation left idle for about 54 minutes is compacted before its one-hour prompt cache expires, so your next message doesn't reprocess it all."

The motivation is cost. Leave a conversation above 200K tokens idle for roughly 54 minutes and it is summarised before the one-hour prompt cache expires, so your next message does not pay to reprocess everything. The prompt caching documentation also notes that Claude Code may compact when idle, and that idleCompaction disables it.

Know what compaction drops before you leave it on
Compaction replaces the conversation layer with a summary. CLAUDE.md itself is re-read from disk, but the contents of files that Claude read because CLAUDE.md told it to are folded into the summary. Context management with /compact and /clear covers the difference. If your workflow depends on what is in the window, turn it off.

New environment variables (2.1.299, 2.1.301, 2.1.302)

CLAUDE_CODE_DISABLE_FILE_MENTIONS is the useful one if @-mentioning a large file keeps filling your context in one shot.

Security fixes (2.1.301, 2.1.302)

• The Read tool loaded an image file of any size — or a pipe or device named like an image — entirely into memory. Image sources over 128 MB are now refused
• Quitting removed a worktree made by a WorktreeCreate hook without asking, even when it might hold unpushed commits

Telemetry

The OpenTelemetry api_request event now splits cache writes by lifetime with cache_creation_5m_tokens and cache_creation_1h_tokens. The tool_decision event gained classifier_verdict, permission_mode and classifier_category, so you can tell an auto mode classifier decision apart from one made by a permission rule.

Codex

Daybreak is the default again (0.163.0)

The release notes say "Daybreak is enabled by default for eligible accounts." In v0.161.0 it required --enable cli_daybreak or features.cli_daybreak=true, and daybreak=true alone was not enough (What changed in Codex CLI v0.161 and v0.162). Five days and a reversal later, this is not a setting to treat as settled.

/config and steering (0.163.0)

• /config: search preferences across categories, change supported ones in place, and see which changes need a restart
• Follow-ups mid-response: send a follow-up while Codex is responding to steer it immediately. Interrupting a turn also stops running Code Mode cells and nested tool calls
• Leader key in /keymap: the default is Ctrl+X. Voice mute moved to F9
• Parallel read-only tools: independent reads such as skills, memories and conversation history now run in parallel

Network and sandbox (0.163.0)

Three proxy fixes landed: the network proxy now checks permission before a DNS lookup, rejects duplicate Host headers, and prevents credential aliases from bypassing inspection hooks. Resuming a saved thread now restores its permission and network approvals too.

One operational change: Codex no longer bundles a patched zsh and uses its standard shell executor instead. Configurations using the retired shell flags get a migration notice.

Gemini CLI

v0.64.0 is fixes only. The notable ones: a CPU hang and swallowed quotes when @ appears in code, file tool operations serialised with atomic writes, and atomic state persistence with recovery from a backup when the file is corrupt. On Windows, ConPTY now forwards the IME cursor position.

What to check now

1. Decide how you feel about idle compaction. If you do not want conversations summarised unprompted, turn it off in /config or with "idleCompaction": false
2. If you had explicitly disabled Daybreak in Codex, check its current state — the default moved
3. Upgrade Claude Code to 2.1.302 or later if the Read tool image issue matters to you
4. Upgrade Codex to 0.163.0 if you restrict network access in the sandbox, for the pre-DNS permission check

Summary

• Claude Code now compacts idle conversations: 200K+ tokens left for about 54 minutes
• Turn it off with "idleCompaction": false, tune it with CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS, toggle it in /config
• CLAUDE_CODE_DISABLE_FILE_MENTIONS passes @ mentions as paths instead of contents
• Codex 0.163.0 made Daybreak the default again for eligible accounts, reversing v0.161.0
• Gemini CLI v0.64.0 is fixes only