The lab works with two credentials:

• A Claude setup token (CLAUDE_CODE_OAUTH_TOKEN), created by python3 lab.py tokens claude. It is valid for one year; the lifetime cannot be shortened.
• A fine-grained GitHub personal access token (GH_TOKEN), created by python3 lab.py tokens github. It is valid for one day and limited to the lab's GitHub organization.

Both are stored only in .env, which the lab writes with mode 600 and which git ignores, and in the environment of the child processes that need them. They never appear in command-line arguments, and the lab prints them only masked. Preflight refuses to run if .env is tracked by git or has another mode.

The lab creates public test repositories in your organization and deletes them again on the next run or on teardown.

The lab separates runs from each other and from your own Claude config. It does not protect your machine from the model under test:

• The model runs as your user, with both tokens in its environment and with unscoped Read, Edit, Write and Bash(...) allow rules. It can read and write files your user can, including the .env file two directories above its working directory.
• Transcripts under sandbox/*/results/ contain whatever Claude printed or read during a run.

Run the lab under a dedicated user account, in a VM or in a devcontainer, and do not share the sandbox/ results.

• Use a new, dedicated GitHub organization that holds nothing but the lab's repositories. The GitHub token has write access to every repository in it, including GitHub Actions workflows.
• Revoke both tokens after the lab: python3 lab.py teardown --secrets. It revokes the GitHub token, guides you through revoking the Claude token on claude.ai, and checks both. If it cannot prove a token is revoked, it says so and names the page where you can check.
• Don't share or record your screen while python3 lab.py tokens claude runs. Claude Code's login screen shows the new token; the lab masks it where it can, but not reliably. The same applies to the GitHub token page during python3 lab.py tokens github.