tools/claim.sh is the semantic mutex: exclusive keys cannot be co-owned by two active claims on this machine. worktree-new/done seed, claim, and prune private targets. check.sh --land names the land gate; heartbeat.sh writes gitignored run status so empty logs are not the only progress signal. Slices A/B/D/G of agent-scale.md held; C/E/F open. Defense: Implements wiki/process/agent-scale.md acceptance criteria for slices A, B.1-B.2, D, and G (claims, land alias, worktree bootstrap/prune, heartbeats).