Claude Code v2.1.154: Opus 4.8, Dynamic Workflows, and Major Fixes

Anthropic released Claude Code v2.1.154, adding Claude Opus 4.8 and dynamic workflows. The model defaults to high effort; use /effort xhigh for the hardest tasks. Fast mode is available at 2x the standard rate for 2.5x speed — a significant cost reduction.
Dynamic Workflows
The headline feature: you can now ask Claude to create a workflow, and it orchestrates work across tens to hundreds of background agents for larger, more complex tasks. Use /workflows to view running workflows.
Agent & Shell Enhancements
In claude agents, prefix a shell command with ! to run it as a background session you can attach/detach from. The equivalent CLI flag is claude --bg --exec '<command>'. Also, /logout now actually signs you out (not sent to a background session). The agents view (double left arrow) now works on Bedrock, Vertex, Foundry, and with telemetry disabled.
Plugin Changes
Plugins can now declare defaultEnabled: false in plugin.json or a marketplace entry. Enable them with /plugin or claude plugin enable; dependencies remain auto-enabled. The Discover tab pins plugins matching your current directory with a “suggested for this directory” annotation.
Other Notable Improvements
- Lean system prompt is now default for all models except Haiku, Sonnet, and Opus 4.7 and earlier.
- Multiple-choice prompts are reserved for decisions Claude genuinely cannot make.
/simplifynow runs a cleanup-only review (reuse, simplification, efficiency, altitude) and applies fixes — no longer runs full bug-hunting/code-review --fix.- Streaming tool execution is always enabled, including on Bedrock/Vertex/Foundry and with telemetry disabled.
- Stdio MCP server subprocesses receive
CLAUDE_CODE_SESSION_IDandCLAUDECODE=1environment variables. /chromelets you pick which connected browser to use when multiple are connected.
Bug Fixes
- Fixed
rm -rf $HOMEnot being blocked whenHOMEhas a trailing slash. - Fixed
$TMPDIRresolving inconsistently between sandboxed and unsandboxed Bash commands. - Fixed pinned background sessions respawning every minute after a Claude Code update, causing notification churn.
- Fixed subagents in background sessions bypassing worktree-isolation guard and writing to shared checkout.
- Fixed orphaned
claude --bg-pty-hostprocesses spinning at 100% CPU on macOS. - Fixed
worktree.baseRef: "head"resolving to main checkout’s HEAD instead of current worktree’s HEAD. - Fixed intermittent terminal rendering corruption in VS Code (capped spinner colors).
- Many others, including background session state management, keyboard shortcuts, and classifier detection of data exfiltration.
📖 Read the full source: GitHub Claude-Code
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