A Claude Code environment variable, read out of the shipped bundle.
It has been in the build since v2.1.203, including the newest one read.
Terminal size passed to a relaunched Claude Code process, as <columns>x<rows>. Claude Code sets it from the current stdout size when it re-executes or respawns itself; at startup the new process deletes it from its environment and, when stdout is a TTY and both numbers are 1 to 4 digits with no leading zero, uses them for process.stdout.columns and rows where those are unset or zero.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.286 bundle, and it can be wrong.
First seen v2.1.203 7 Jul 2026
Last seen v2.1.308 22 Oct 2026
Builds94 / 149on this box, as of v2.1.308
Written about v2.1.203 first named in a changelog, 7 Jul 2026
v2.1.203in the build not in the build never minedv2.1.308
In the changelogs
1
Releases whose published page names CLAUDE_CODE_RELAUNCH_TERMINAL_SIZE.
The earliest release whose published evidence quoted CLAUDE_CODE_RELAUNCH_TERMINAL_SIZE was v2.1.203, 7 Jul 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
v2.1.203 – v2.1.30894 builds7 Jul 2026 → 22 Oct 2026 ◆in the build
Build by build
94
One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the environment variable does. All environment variables.
