Tmux scrollback broken after May 26 update (v2.1.152)

Status Fixed / completed

Reported on v2.1.152

Maintainer reply ✓ Yes — bcherny

Activity 3 comments · opened May 27, 2026 · closed Aug 19, 2026

💡 Likely answer: A maintainer (bcherny, collaborator) responded on this thread — see the highlighted reply below.

Description

After the update to v2.1.152 (installed May 26, 2026), tmux scrollback no longer works in the Claude Code pane. Sessions opened before the update scrolled fine; all sessions opened after the update cannot scroll back through conversation history.

Steps to Reproduce

Open a new tmux pane
Run claude
Have a conversation long enough to scroll
Attempt to scroll up with tmux copy mode (prefix + [)

Expected Behavior

Able to scroll back through previous conversation output in the tmux pane, as was possible before v2.1.152.

Actual Behavior

Cannot scroll back beyond the current screen. Other tmux panes (not running Claude Code) scroll back normally, so the tmux scrollback limit is not the issue.

Environment

Claude Code version: 2.1.152
OS: macOS (Darwin 25.5.0)
Terminal multiplexer: tmux

Hypothesis

Claude Code may have switched to using the alternate screen buffer in this update, which prevents tmux from capturing output in the main scrollback buffer. Previous versions did not appear to use the alternate screen.

View original on GitHub ↗

3 Comments

renxzen · 4 months ago

This is a quick workaround atm:

https://github.com/anthropics/claude-code/issues/60185#issuecomment-4558148544

bcherny collaborator · 1 month ago

The fullscreen renderer draws on the terminal's alternate screen buffer, so tmux copy mode doesn't see the conversation by design — press Ctrl+O then [ to write the conversation into native scrollback, or run /tui default (or set CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1) to keep the classic renderer — see https://code.claude.com/docs/en/fullscreen. Closing — reply to reopen.

🤖 Generated with Claude Code

github-actions[bot] · 5 days ago

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