CLAUDE_CODE_DIFF_COPY_ROOT

Updated October 21, 2026 by Alex Sorokoletov

CLAUDE_CODE_DIFF_COPY_ROOT is a Claude Code environment variable: A self-hosted runner names, in this variable, the folder holding the checked copy of a repository's git settings that Claude Code reads for a workspace diff and nested-repository detection. Added in v2.1.307 and still present in v2.1.307. It is not in the official reference.

Status	Present in v2.1.307
Added	Added in v2.1.307
Category	Other
Official docs	Not listed

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CODE_DIFF_COPY_ROOT=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_DIFF_COPY_ROOT": "<value>"
  }
}

Release notes that mention it

claude-code-env-vars-v2-1-307

Related variables

CLAUDE_CODE_TEST_FIXTURES_ROOT: Root directory for test fixtures.
CLAUDE_STAGE_FILE_ROOT
ANTHROPIC_BETAS: Comma-separated beta feature headers.
ANTHROPIC_CUSTOM_HEADERS: Custom HTTP headers (newline-separated Key: Value).
ANTHROPIC_FEDERATION_RULE_ID
ANTHROPIC_ORGANIZATION_ID
ANTHROPIC_WORKSPACE_ID
BETA_TRACING_ENDPOINT: Custom endpoint for beta tracing.

Frequently asked questions

What does CLAUDE_CODE_DIFF_COPY_ROOT do?

A self-hosted runner names, in this variable, the folder holding the checked copy of a repository's git settings that Claude Code reads for a workspace diff and nested-repository detection.

Which Claude Code version has CLAUDE_CODE_DIFF_COPY_ROOT?

Added in v2.1.307 and still present in v2.1.307.

How do I set CLAUDE_CODE_DIFF_COPY_ROOT?

Export it before starting Claude Code (export CLAUDE_CODE_DIFF_COPY_ROOT=value), or add it to the "env" object in ~/.claude/settings.json to apply it to every session.

All variables, searchable: Claude Code environment variables.