Originally published at https://aicoding-guide.com. This week has a deadline in it. Fast mode for Opus 4.8 is deprecated as of 2026-10-30 and removed on 2026-11-30. The CHANGELOG is specific that after removal, fast mode requests on Opus 4.8 return an error and do not fall back to standard Opus 4.8.
On the feature side, idle compaction spread to VS Code and the desktop app — two weeks after it arrived, terminal-only.
Key point
This week in brief
- Fast mode on Opus 4.8 is removed on November 30; move to Opus 5.5 to keep the speedup
- Idle compaction was added to VS Code and the desktop app's Code tab
permissions.blockWritesOutsideWorkingDirectorieswas added
Four releases: 2.1.311, 2.1.312, 2.1.314 and 2.1.316.
The CHANGELOG reads: "Deprecated fast mode for Opus 4.8 as of October 30, 2026; it will be removed on November 30, 2026. After removal, fast mode requests on Opus 4.8 return an error and do not fall back to standard Opus 4.8. Migrate to Opus 5.5 to keep the speedup."
If a script or settings file assumes fast mode, move it to Opus 5.5 during November. After removal it does not quietly get slower — it errors.
| Setting | What it does |
|---|---|
permissions.blockWritesOutsideWorkingDirectories |
Write, Edit and NotebookEdit refuse paths outside the working directories in every permission mode |
It pairs with permissions.blockReadsOutsideWorkingDirectories on the read side. With both set, the reach of the file tools no longer depends on the permission mode.
"Added idle compaction to VS Code and Claude Desktop's Code tab: a 200K+ token conversation left idle is summarized, and the summary is used on your next message if the prompt cache has expired."
What landed in the terminal in 2.1.299 reached VS Code and the desktop Code tab two weeks later. For the conditions and how to turn it off, see Making Claude Code compact earlier, or never.
| Variable | What it does |
|---|---|
CLAUDE_CODE_DISABLE_ULTRATHINK |
Turns the ultrathink keyword off |
CLAUDE_CODE_SUBAGENT_EFFORT |
Sets the effort subagents run at when nothing else names one, instead of inheriting the session's |
claude_code.safety_event stopped being sent after a week
The claude_code.safety_event OpenTelemetry event added in v2.1.307 was withdrawn in v2.1.312: "Changed Claude Code to stop sending the claude_code.safety_event OpenTelemetry event." We covered it in last week's digest; it lasted a week. A dashboard built on that event needs rebuilding.
On security, --restricted sessions could upload files from outside the working directories when a Read allow rule covered them; that is fixed. Separately, for Team and Enterprise logins, server-managed settings fetched from Anthropic's API now apply without an approval prompt, and a stored copy that doesn't verify is refused.
PreCompact hook with very large output could make compaction fail or repeat; CLAUDE.md, rules file or @-included file after seeing only its start; Write now asks Claude to read it all or edit in place (2.1.312)SubagentStop hooks were firing about twice a minute per running subagent instead of once at the end (2.1.311)
v0.165.0 brought the Vertex AI provider and memories by default; see Codex CLI v0.165. v0.166.0 adds six features.
| Addition | What it does |
|---|---|
codex queue --resume |
Resumes unloaded threads after queueing a message |
codex doctor --network-only |
Runs focused configuration, connectivity and WebSocket diagnostics |
| Transcript selection | Keyboard-driven, with word, line and page motions, search and configurable shortcuts |
| GPT-6.1 Terra | Added to the bundled, Vertex AI and Amazon Bedrock model catalogs |
| Safety-block explanations | Clearer reasons in the TUI, with selectable safer follow-up prompts |
Two fixes stand out, both about resuming: acknowledged approval and permission settings are now preserved when resuming or forking threads, and reasoning-token accounting is preserved across resume and fork to avoid premature compaction.
v0.66.0 is 26 entries of fixes and chores with no features. The configuration-related ones:
.env files are loaded~/.gitconfig is preserved in shell and git environmentsgetSafeGitEnv
keybindings.json supports a keys array
A banner was also added saying Gemini CLI is not optimized for Gemini 4. For the previous release, see Gemini CLI v0.65 enforces read-only settings in untrusted folders.
claude_code.safety_event
permissions.blockWritesOutsideWorkingDirectories if you want writes confinedcodex queue --resume and codex doctor --network-only