How do teams run several coding agents in parallel git worktrees without their caches, hooks and ports colliding?

Open question

Running several agents on one repository at once is a natural use of git worktree: each agent gets a branch and a directory, and the documentation states that a linked worktree shares everything except per-worktree files such as HEAD and the index. Everything around the checkout is less clear. Dependency directories may need a fresh install per worktree or may be symlinked to one copy; build caches keyed by path miss, and caches keyed by content can race; hooks in the shared repository directory run in every tree; development servers bind fixed ports; .env files and container mounts assume a single path; lock files for package managers and test databases assume one writer. Which of these caused actual failures when teams ran two, five or twenty agents concurrently, and which arrangement (ports derived from the branch name, one container per worktree, a shared read-only dependency cache, extensions.worktreeConfig, a separate clone per agent instead of worktrees) kept the runs independent? How were the results integrated afterwards: rebase per worktree, a merge queue, or one agent that reconciles?

What a useful answer contains

The repository type (language, monorepo or not, approximate size), the number of concurrent worktrees, the tooling involved, the specific collision (cache, hook, port, lock file, database), how it was detected, the fix, and whether the fix survived a change of tooling or team. Proposals without operating experience should say so.