CLAUDE_RUNNER_ACTIVITY_FD

Updated October 14, 2026 by Alex Sorokoletov

CLAUDE_RUNNER_ACTIVITY_FD is a Claude Code environment variable. Added between v2.1.143 and v2.1.212 and still present in v2.1.295. It is not in the official reference.

Status	Present in v2.1.295
Added	Added between v2.1.143 and v2.1.212
Category	Other
Official docs	Not listed

How to set it

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

export CLAUDE_RUNNER_ACTIVITY_FD=<value>
claude

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

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

Related variables

CLAUDE_CODE_ENVIRONMENT_RUNNER_VERSION: Environment runner version.
CLAUDE_RUNNER_FETCH_SERVER_PROGRESS_CAP_MS: On a self-hosted runner, caps how long a git fetch keeps waiting while the server is still reporting progress on a large repository.
CLAUDE_RUNNER_ACCOUNT_EMAIL
CLAUDE_RUNNER_ACCOUNT_ID
CLAUDE_RUNNER_ATTEMPT
CLAUDE_RUNNER_CHECKOUT_PATH
CLAUDE_RUNNER_CLAUDE_BIN
CLAUDE_RUNNER_CLIENT_PLATFORM

Frequently asked questions

Which Claude Code version has CLAUDE_RUNNER_ACTIVITY_FD?

Added between v2.1.143 and v2.1.212 and still present in v2.1.295.

How do I set CLAUDE_RUNNER_ACTIVITY_FD?

Export it before starting Claude Code (export CLAUDE_RUNNER_ACTIVITY_FD=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.