Claude Code v2.1.154 の更新：Opus 4.8 の高効率デフォルト化と動的ワークフローの導入

What's changed

• Opus 4.8 is here! Now defaults to high effort · /effort xhigh for your hardest tasks

• Introducing dynamic workflows: ask Claude to create a workflow and it orchestrates work across tens to hundreds of agents in the background, so you can take on larger, more complex tasks. Run /workflows to view your runs

• Fast mode on Opus 4.8 is now available at a fraction of its previous cost: 2x the standard rate for 2.5x the speed

• The lean system prompt is now the default for all models except Haiku, Sonnet, and Opus 4.7 and earlier

• Claude now reserves the multiple-choice question prompt for decisions it genuinely cannot make itself, instead of asking when it already has enough context to proceed

• /simplify now runs a cleanup-only review (reuse, simplification, efficiency, altitude) and applies the fixes, instead of running the full /code-review --fix bug-hunting review

• Renamed the /effort slider labels from "Speed"/"Intelligence" to "Faster"/"Smarter" for clarity

• claude agents: type ! to run a shell command as a background session you can attach to and detach from. Also available as claude --bg --exec ''

• claude agents: /logout now signs you out instead of being sent to a background session

• ←← to open the agents view now works on Bedrock, Vertex, Foundry, and with telemetry disabled

• Claude in Chrome: pick which connected browser to use via /chrome → "Select browser…", or in-chat when a browser action runs with multiple connected

• Plugins can now declare defaultEnabled: false in plugin.json or a marketplace entry; enable them with /plugin or claude plugin enable. Dependencies of enabled plugins are still enabled automatically

• The /plugin Discover tab now pins plugins whose relevance signals match the current directory with a "suggested for this directory" annotation

• Streaming tool execution is now always enabled, including when telemetry is disabled or on Bedrock/Vertex/Foundry (previously behind a feature flag)

• Stdio MCP server subprocesses now receive CLAUDE_CODE_SESSION_ID and CLAUDECODE=1 in their environment

• claude mcp list/get now show unapproved .mcp.json servers as ⏸ Pending approval instead of auto-approving and connecting when output is piped

• /remote-control autocomplete now shows "Disconnect Remote Control" when Remote Control is already active

• Added Claude Opus 4.8 support and 4.7 → 4.8 migration guidance to the /claude-api skill

• Deprecated CLAUDE_CODE_OPUS_4_6_FAST_MODE_OVERRIDE (will be removed on 06/01). To use fast mode on Opus 4.6, switch with /model claude-opus-4-6[1m] and then /fast on

• Improved the auto-mode classifier's detection of data exfiltration, particularly bulk transfers of repository contents

• Fixed rm -rf $HOME not being blocked as a dangerous path when HOME has a trailing slash

• Fixed $TMPDIR resolving to different directories in sandboxed vs unsandboxed Bash commands within the same session

• Fixed unreadable highlighted-row text in claude agents when the Claude Code theme doesn't match the terminal background

• Fixed background-agent completion notifications triggering premature "out of context" behavior on some 1M-context models

• Fixed background-session classifier losing the user's goal when a scheduled /command fires

• Fixed pinned background sessions respawning every minute after a Claude Code update, causing repeated agent-start notifications and process churn at idle

• Fixed background sessions stuck at "blocked", "running", or "working" not retiring after the idle grace period

• Fixed subagents in background sessions bypassing the worktree-isolation guard and writing to the shared checkout

• Fixed orphaned claude --bg-pty-host processes spinning at 100% CPU after the daemon exits on macOS

• Fixed number key shortcuts not working for options shown below the divider in option dialogs

• Fixed worktree.baseRef: "head" resolving to the main checkout's HEAD instead of the current worktree's HEAD when spawning subagents or calling EnterWorktree from inside a linked worktree

• Fixed a stray leading space on wrapped lines when the previous line ended exactly at the terminal width

• Fixed intermittent terminal rendering corruption in VS Code by capping the number of distinct colors the thinking spinner produces

• Fixed plan file names including [Image #N] / [Pasted text #N] placeholders when a plan-mode prompt starts with pasted images or text

• Fixed a phantom expand/click affordance on colored tool output: short ANSI-colored lines that fit on screen no longer show a "ctrl+o to expand" hint

• Fixed a single invalid allowedMcpServers/deniedMcpServers entry in managed settings discarding all managed-settings policy; the bad entry is now dropped with a claude doctor warning

• Fixed API 400 errors on models that don't support the effort parameter when CLAUDE_CODE_ALWAYS_ENABLE_EFFORT is set

• Windows: Fixed update failures caused by claude.exe being in use showing a generic error instead of telling you to close other sessions and retry

• Removed the stale "& for background" hint from the shortcuts help panel

• [VSCode] Auto mode no longer requires the bypass-permissions setting to appear in the mode picker, and a dismissable notice on the new-session screen explains auto mode the first time it's active

• Fixed the task panel below the prompt showing a stray unselectable "main" row when only a workflow is running

• Fixed /mcp tools list and tool detail rendering when MCP servers have long or multi-line tool names or long descriptions

• Fixed the /model picker not showing fast mode pricing on the Default option for API (pay-as-you-go) users when fast mode is on

• Fixed auto mode incorrectly blocking actions with "could not evaluate this action" when the safety classifier ran out of output tokens while reasoning