CLAUDE_CODE_DIR_SYNC_CHAIN
A Claude Code environment variable, read out of the shipped bundle. It was in the build from v2.1.280 and was gone by v2.1.283.
A new 'chained' directory-sync mode exists behind an undocumented CLAUDE_CODE_DIR_SYNC_CHAIN env var
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.280.
In the changelogs
4Releases whose published page names CLAUDE_CODE_DIR_SYNC_CHAIN.
-
v2.1.283
Directory sync always sends changes as linked bundles, with no env var needed
Chained pushes in cloud directory sync are now always on, and
CLAUDE_CODE_DIR_SYNC_CHAINis no longer readfound in this entry's text
-
v2.1.281
Directory sync link-chain shipping on the cloud worker depends on a laptop env var
--clouddirectory sync can send each turn's changes as linked bundles, but only when the laptop setsCLAUDE_CODE_DIR_SYNC_CHAINfound in this entry's text, named in this entry
-
v2.1.280
A 'chained' directory-sync mode exists, gated by an undocumented env var
A new 'chained' directory-sync mode exists behind an undocumented CLAUDE_CODE_DIR_SYNC_CHAIN env var
found in this entry's text, named in this entry
-
v2.1.280
Windows-specific env vars added to the host-passthrough allowlist
More environment variables, including Windows-specific ones, now pass through to Claude Code
found in this entry's text
First cited
2The earliest release whose published evidence quoted CLAUDE_CODE_DIR_SYNC_CHAIN was v2.1.280, 22 Sep 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
2Build by build
39One 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.