Worktree & PR

A worktree buys two things: the main working copy stays usable while the task runs, and the untouched copy remains available as a baseline to compare against. Both are worth real setup cost, and neither applies to every change.

This covers the isolation mechanics. How large the change itself should be is scoped-change, and it applies inside a worktree exactly as it does anywhere else.

Deciding

Consider a worktree when at least one holds: the task is large enough that a half-finished state would block other work, several tasks need to progress on the same repository at once, the result has to be compared against current behavior, or the change is risky enough that abandoning it should cost nothing.