Claude Code 2.1.154 - リリースノート

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以下は、Claude Code 2.1.154 のリリースノートの要約です。

⚠️ 破壊的変更 / セキュリティ修正

• 非推奨化（削除予定）: 環境変数 CLAUDE_CODE_OPUS_4_6_FAST_MODE_OVERRIDE が非推奨となり、06/01 に削除予定。今後は /model claude-opus-4-6[1m] + /fast on を使用。
• セキュリティ強化: 自動モードの分類器において、リポジトリ内容の大量転送などデータ流出の検出を向上。
• セキュリティ修正: rm -rf $HOME のような危険なパス指定が、HOME の末尾にスラッシュがある場合にブロックされなかった不具合を修正。
• ポリシー修正: 管理対象設定（managed settings）内の単一の無効な allowedMcpServers/deniedMcpServers エントリが、設定全体を破棄してしまう問題を修正。

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主な変更点・新機能

• Opus 4.8 のデフォルト採用: 最新モデル Opus 4.8 がデフォルトに。高い推論能力が求められるタスクでは /effort xhigh が適用されます。
• 動的ワークフロー（Dynamic workflows）の導入: 数十〜数百のエージェントをバックグラウンドで協調させるワークフローを作成可能。/workflows で実行状況を確認できます。
• Opus 4.8 Fast mode: 従来より低コスト（標準レートの2倍で2.5倍の高速化）で利用可能になりました。
• Lean system prompt のデフォルト化: Haiku, Sonnet, Opus 4.7 以前を除くすべてのモデルで lean system prompt がデフォルト適用されます。
• /simplify コマンドの変更: フルレビュー（/code-review --fix）ではなく、クリーンアップ（再利用・簡略化・効率化）に特化したレビューと修正を適用するよう変更。
• バックグラウンド実行の改善: claude agents で ! <command> と入力することで、シェルコマンドをバックグラウンドセッションとして実行・アタッチ・デタッチ可能（claude --bg --exec も利用可能）。
• ストリーミングツール実行の常時有効化: テレメトリ無効時や Bedrock/Vertex/Foundry 環境でも機能フラグなしで常に有効化。
• MCP サーバーの保留ステータス表示: パイプ出力時に .mcp.json の未承認サーバーが自動承認されなくなり、⏸ Pending approval として表示されるよう変更。
• 多数の不具合修正: VS Code でのレンダリング崩れ、バックグラウンドセッションの停止・CPU占有（macOS）、コンテキスト不足の誤発火など、多数の安定性・UIバグを修正。

原文（Release Notes）

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