Function build_worker_extra_args 

fn build_worker_extra_args(
    is_git_repo: bool,
    label: &str,
    interactive: bool,
) -> Vec<(String, Option<String>)>

Build the list of (flag, value) extra CLI args specific to a worker spawn. When the project is a git repo, append ("worktree", Some(label)) so the spawned claude subprocess creates a worktree at <base>/.claude/worktrees/<label>/ - base the repo’s canonical root, the main checkout for a project that is itself a linked worktree - and runs the session inside it. In all cases, append the worker’s blocked_tools_for set as its --disallowedTools entry: workers are pinned to their spawn-time location (whether a worktree or the project cwd) and must not be able to call claude’s built-in worktree-hop tools to escape. Comma-separated value form is empirically accepted by the CLI’s variadic <tools...> parser.

Unless interactive, AskUserQuestion joins that list. A worker’s question renders in its own row, which nobody is usually looking at, and an answer that does arrive is indistinguishable from a decision the user made. Denying it at spawn means the capability is never offered rather than refused after the model has already decided to ask.

The is_git_repo boolean is passed in (already-computed by the caller) so the git-repo probe runs at most once per spawn even when the same answer is needed for both the WorkerEntry.is_git_repo_at_spawn field and this argument list.