## 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