2.1.154 — Claude code - Product release notes & changelog tool

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