What probably matters to youSection of the release
What
Starting a self-hosted runner on Windows without a base directory now fails with an explanatory error instead of silently falling back to a POSIX container path that does not exist there. Set --base-dir or the SELF_HOSTED_RUNNER_BASE_DIR environment variable to the directory repositories should be checked out under. The runner also now passes CLAUDE_RUNNER_CLIENT_PLATFORM into spawned runner environments, parsed as client_platform.
Details
Passing --base-dir records where the value came from.
Usage
claude ... --base-dir C:\runner\repos
Evidence
--base-dir (or SELF_HOSTED_RUNNER_BASE_DIR) is required on Windows: the built-in default is a POSIX container path that does not apply there. Pass the directory that repositories should be checked out under.
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeChanged self-hosted runner Windows startup to require an explicit --base-dir; there is no default checkout directory on Windows
