Claude Code v2.1.191: /rewind, 37% Less CPU

Claude Code v2.1.191 is an update released on June 24, 2026 that introduces the /rewind command for resuming conversations after /clear, reduces streaming CPU usage by 37%, and adds MCP retry logic for transient network errors plus memory of approved sandbox hosts.

Anthropic releases Claude Code v2.1.191 with two performance and two infrastructure improvements

Anthropic released Claude Code v2.1.191 on June 24, 2026 at 21:58 UTC — the agentic coding CLI that extends available resources through MCP (Model Context Protocol) tools — the same day an earlier v2.1.190 was released (bug fixes only, 15:53 UTC). The new version delivers four concrete changes that directly affect day-to-day use of the tool.

What is /rewind and why was its absence a problem?

Until now, the /clear command erased the entire conversation context with no way to recover it — users who ran it accidentally had to repeat the full task description. /rewind solves this problem: it restores context from the previous session state, without losing progress. Unlike v2.1.187, which focused on security isolation with the sandbox.credentials setting, v2.1.191 delivers an ergonomic upgrade that reduces friction in long agentic workflows.

Streaming CPU usage reduced by 37%

Streaming responses — continuously receiving text from the model as it appears in the terminal — previously triggered a screen redraw on nearly every incoming token. Coalescing text updates, i.e. grouping multiple consecutive messages into a single refresh, reduced CPU load by 37% compared to previous versions. The improvement is especially noticeable during long sessions, for users with many parallel windows, or on machines with limited resources.

MCP retry logic and sandbox host memory

MCP servers — external tools that give Claude Code access to files, databases, APIs, and other resources — previously had no automatic recovery from brief network interruptions. The new retry mechanism repeats a call on transient errors, reducing the number of missed tool calls in unstable network environments. In addition, sandbox network permissions now remember previously approved hosts — users no longer need to manually confirm the same host multiple times within a session.

Bug fixes and development pace

Version 2.1.191 fixes bugs specific to Windows Terminal and the Ghostty terminal emulator. Anthropic continues its daily delivery rhythm: v2.1.190 and v2.1.191 shipped the same day, continuing the trend from v2.1.187 where each version brought concrete improvements alongside fixes from the previous day.

Frequently Asked Questions

What does the /rewind command do and when should you use it?

/rewind restores the conversation context that /clear erased — useful when you accidentally cleared a session mid-task and want to resume from where you left off without re-describing the entire context.

Why does a 37% CPU reduction matter in practice?

Streaming responses — continuously receiving text from the model — previously triggered a screen redraw on nearly every token received. Coalescing text updates, i.e. grouping multiple text messages into a single screen refresh, reduced CPU load by 37% compared to v2.1.187, which is especially noticeable during long sessions and on slower machines.

Anthropic: Claude Code v2.1.191 — /rewind command, 37% less CPU, MCP retry logic