CLAUDE_CODE_CLIENT_DATA_URL
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.283, including the newest one read.
--client-data-url or CLAUDE_CODE_CLIENT_DATA_URL loads a signed per-model configuration from Anthropic, and Claude Code will not start if it fails
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.283.
In the changelogs
6Releases whose published page names CLAUDE_CODE_CLIENT_DATA_URL.
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v2.1.302
Signed client data now stops startup when it has no entry for your model
With
--client-data-url, Claude Code now exits if the document has no entry for your model, unless--allow-other-modelsis setfound in this entry's text, named in this entry
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v2.1.300
Signed client configuration is now checked against your organisation
A signed configuration document is now matched to your logged-in organisation and refused if the signing organisation differs
found in this entry's text, named in this entry
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v2.1.295
Remote sessions start loading the client data URL earlier at startup
Remote workers now begin fetching the document at the client data URL while Claude Code starts up, and the proxy gets a token even when none is passed
found in this entry's text, named in this entry
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v2.1.295
Client data document loads earlier and can mark a base URL as Anthropic's
Claude Code now starts loading the CLAUDE_CODE_CLIENT_DATA_URL document early, and the document can mark the base URL as the Anthropic API
found in this entry's text, named in this entry
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v2.1.287
--client-data-url no longer appears in --help
--client-data-urlis now hidden from--helpoutput but still works as beforefound in this entry's text, named in this entry
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v2.1.283
New
--client-data-urlflag loads a signed configuration for your model--client-data-urlorCLAUDE_CODE_CLIENT_DATA_URLloads a signed per-model configuration from Anthropic, and Claude Code will not start if it failsfound in this entry's text, named in this entry
First cited
1The earliest release whose published evidence quoted CLAUDE_CODE_CLIENT_DATA_URL was v2.1.283, 25 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
1Build by build
36One 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.