CLAUDE_CODE_VERSION

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_VERSION is a Claude Code environment variable: Exposes the CLI version to subprocesses, hooks, and MCP servers. Your hooks and MCP tools can now read CLAUDE_CODE_VERSION directly — gate behavior on minimum version, log it for observability, or refuse to run on an incompatible version. Added between v2.1.128 and v2.1.138 and still present in v2.1.294. It is not in the official reference.

Status	Present in v2.1.294
Added	Added between v2.1.128 and v2.1.138
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_VERSION=<value>
claude

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

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

Release notes that mention it

Claude Code v2.1.143 — 27 New Env Vars, /goal, Agent View, and a Free Model Upgrade

Related variables

CLAUDE_CODE_ENVIRONMENT_RUNNER_VERSION: Environment runner version.
CLAUDE_CODE_DESKTOP_APP_VERSION
CLAUDE_SSH_VERSION
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

Frequently asked questions

What does CLAUDE_CODE_VERSION do?

Exposes the CLI version to subprocesses, hooks, and MCP servers. Your hooks and MCP tools can now read CLAUDE_CODE_VERSION directly — gate behavior on minimum version, log it for observability, or refuse to run on an incompatible version.

Which Claude Code version has CLAUDE_CODE_VERSION?

Added between v2.1.128 and v2.1.138 and still present in v2.1.294.

How do I set CLAUDE_CODE_VERSION?

Export it before starting Claude Code (export CLAUDE_CODE_VERSION=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.