Git Worktree Setup

Start implementation in an isolated workspace without taking ownership of a worktree that the user or harness already manages.

Quick Path

1. Read repository instructions and inspect Git state before changing anything.
2. Detect whether the current checkout is already a linked worktree, including the submodule exception below. Reuse it when it is.
3. If isolation is not already present, create it when the user has asked for a worktree or the active mission already grants isolation. Do not ask again for the same scope; an inspection-only request still does not grant creation.
4. Honor an explicit creation mechanism or directory policy. Otherwise create a Git worktree under the repository's .worktrees/ directory. Use native creation when the user asks for harness-managed lifecycle behavior.
5. Run repository-defined setup and the smallest meaningful baseline check.
6. Report the path, branch state, creation mechanism, and validation evidence.

Detect Existing Isolation

Resolve both paths rather than comparing Git's sometimes-relative output: