Claude Code can now block writes outside your project, and Opus 4.8 fast mode ends

Claude Code can now block every write outside your project

Setting

permissions.blockWritesOutsideWorkingDirectories

Tools

Write, Edit and NotebookEdit refuse paths outside the working directories

Modes

every permission mode

>Fast mode on Opus 4.8 is deprecated and goes away November 30

Deprecated

October 30, 2026

Removed

November 30, 2026

After that

fast mode requests on Opus 4.8 return an error, with no fall back to standard Opus 4.8

To keep the speedup

move to Opus 5.5

>Claude no longer overwrites a huge CLAUDE.md it only partly saw

Before

Claude saw the start of a very large CLAUDE.md, rules file or @-included file in a subdirectory, then wrote over it

Now

Write asks Claude to read the whole file, or edit in place

>More control over effort, and no more failures from an admin's cap

Admin effort cap

Claude Code lowers the effort, retries, and says which level it uses, instead of failing every turn

CLAUDE_CODE_SUBAGENT_EFFORT

sets the effort subagents run at when nothing else names one

CLAUDE_CODE_DISABLE_ULTRATHINK

turns the ultrathink keyword off

>Fixed for scripts: silent exits, cut-off Bash scripts, leftover commands

claude -p

a startup failure prints the error and exits 1, not 0 with no output

SHELLOPTS exported

Bash tool scripts no longer stop after their first command

Exit on its own

shell commands no longer keep running on macOS and Linux

>VS Code and Claude Desktop now compact a long chat while it sits idle

When

a conversation of 200K tokens or more is left idle

Then

it is summarized, and the summary is used on your next message if the prompt cache has expired

Also on

Bedrock, Vertex, Foundry and LLM gateways once the one-hour prompt cache is on

>Fixed on Bedrock, Vertex and Foundry: falling back instead of failing

Bedrock and Vertex

sonnet, opus and haiku switch to an older model when the newest isn't in your account or region

Foundry

with no deployment for the default Sonnet, Opus or Haiku, it uses an older model of that family

Bedrock images

sessions with many images drop older ones and compact, instead of failing with “Input is too long”

>Anthropic's plugins now install from claude-plugins-official

Installed ids

name@claude-code-plugins keeps working

Renamed

ralph-wiggum is now ralph-loop, and scripts must use the new name

hookify

now enforces block rules that used to fail silently

Every change is in the Claude Code changelog

https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md

Want Claude kept inside your project? Turn on the new write block.