Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.236 Home All releases olderv2.1.235 v2.1.237newer
Claude Code v2.1.236

Terminal title stops animating inside tmux, screen and zellij

You'll notice
Useful3 Signal2
Terminal UI

Inside tmux, screen or zellij your terminal title stays static instead of animating.

Feature flag
tengu_static_title_under_mux Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.236: off

Read once, for one account on one subscription tier, against v2.1.236. It isn't a statement about your account. What a flag value here can and cannot tell you

What

When Claude Code detects a terminal multiplexer, it now renders a static terminal title instead of an animated spinner, and stops scheduling the animation timer at all. The gate tengu_static_title_under_mux defaults to true, so this is live for everyone in a multiplexer unless remote config turns it off.

Details
  • Detection uses the session's multiplexer info or the TMUX, STY and ZELLIJ environment variables.
  • With the condition met, the spinner glyph is dropped from the title and no frame timer runs.
  • Outside a multiplexer, nothing changes.
Evidence

tengu_static_title_under_mux

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.236 →