detect_scope() had the same bug class fixed in new-agent.sh (099bdec):
it checked for a .git directory before checking whether it had reached
$HOME, so a dotfiles-managed home directory (yadm, chezmoi bare-repo,
etc.) made validate.sh misresolve to project scope, deriving the
counterpart as ~/.github/agents/<name>.agent.md instead of the correct
~/.copilot/agents/<name>.agent.md and failing with a false "counterpart
file not found". Check the $HOME boundary before the .git check, same
fix shape as 099bdec.
Found via post-implementation review of issue #89.
Defame1297
ffebdc6584