CLAUDE_RUNNER_CLIENT_PLATFORM
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.301, including the newest one read.
Odd platform labels from the runner are rejected or replaced with "unknown" instead of exported.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.229.
In the changelogs
2Releases whose published page names CLAUDE_RUNNER_CLIENT_PLATFORM.
-
v2.1.229
Runner refuses unsafe client platform labels
Odd platform labels from the runner are rejected or replaced with "unknown" instead of exported.
named in this entry, found in this entry's text
-
v2.1.229
Self-hosted runner requires
--base-diron WindowsSelf-hosted runners on Windows now require you to set a base directory instead of failing oddly.
named in this entry, found in this entry's text
First cited
1The earliest release whose published evidence quoted CLAUDE_RUNNER_CLIENT_PLATFORM was v2.1.229, 12 Aug 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.
Presence across releases
1Build by build
9One 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.