cargo-worktree-builds - Shared Target Dir for Parallel Worktree Agents

When you fan out parallel agents into separate git worktrees of a Rust repo (one per issue/feature), each worktree builds into its own target/ by default. For a project with hundreds of dependency crates that means every worktree pays the full cold dependency build (minutes each) and writes its own multi-GB target/ — so N worktrees cost ≈ N× time and N× disk for dependency artifacts that are byte-identical across them.

Point every worktree at one shared, pre-warmed CARGO_TARGET_DIR instead. Dependencies compile once and are reused; cargo's build lock serializes the concurrent builds (which also caps CPU/I/O thrash); disk stays ≈ 1× not N×.

When to Use This Skill