CLAUDE_CODE_PLAIN_DELTA_DIRECT_WRITE
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.317, including the newest one read.
Claude Code now recognises new environment variables including CLAUDE_CODE_PERSONAL_HOOKS_OFF, and no longer recognises CLAUDE_CODE_LAZY_ENV_GETTERS
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.317.
In the changelogs
2Releases whose published page names CLAUDE_CODE_PLAIN_DELTA_DIRECT_WRITE.
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v2.1.317
Five new environment variables recognised,
CLAUDE_CODE_LAZY_ENV_GETTERSremovedClaude Code now recognises new environment variables including CLAUDE_CODE_PERSONAL_HOOKS_OFF, and no longer recognises CLAUDE_CODE_LAZY_ENV_GETTERS
found in this entry's text
-
v2.1.317
New
CLAUDE_CODE_PLAIN_DELTA_DIRECT_WRITEsetting for faster stream-json outputSetting CLAUDE_CODE_PLAIN_DELTA_DIRECT_WRITE with the fast-path option writes streamed text pieces straight out when the reader is waiting
found in this entry's text, named in this entry
First cited
1The earliest release whose published evidence quoted CLAUDE_CODE_PLAIN_DELTA_DIRECT_WRITE was v2.1.317, 2 Nov 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
2One 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.