Codex Local, Worktree, or Cloud: Choose the Right Boundary

A Git worktree isolates working files for another task but still runs on its host; it is not a security sandbox or an automatic cloud copy. A hosted Codex task uses a configured repository environment with its own setup. Verify environment details rather than inferring them from the interface.

Know whether the project is a Git repository and whether there are uncommitted changes. Identify required local services, credentials, and generated files. Do not assume any environment automatically contains another checkout’s uncommitted work.

Direct local work is simple when only one worker is changing files. A worktree can keep a separate label patch from colliding with the homepage checkout. A cloud task may be useful for a configured repository, but a local preview service or uncommitted stylesheet will not become available merely because you ask for it.

• Local check: confirm the current directory and preserve pending edits.
• Worktree check: confirm starting revision and changed-file list before and after work.
• Hosted check: confirm dependency setup, available repository state, and how the returned diff will be reviewed.

1. List the task’s required files and services. Choose the environment that actually contains or can safely provision them.
2. Record the starting revision or state and the verification command for that environment.
3. Give the task a narrow file boundary even when using a separate checkout.
4. Review the resulting diff before integration. Resolve conflicts deliberately and retain the task’s evidence before any cleanup.

A useful environment choice includes a concrete transfer plan: which patch returns, where it will be reviewed, and which checks must be rerun after integration. File isolation reduces collisions but does not prove a patch is correct.

Stop if the task depends on unavailable local state, setup asks for excessive secrets, or the worker is about to discard a checkout containing unreviewed changes. Ask for a safe handoff rather than deleting evidence to tidy the workspace.

• Did the worker begin from the intended state?
• Are environment-specific limitations disclosed?
• Will the integrated result be tested again in its destination checkout?