- agent/node_pool.py: NodePool class creates shared stateless node instances, excludes stateful roles (sensor, memorizer, ui) - agent/nodes/base.py: _current_hud contextvar for per-task HUD isolation, Node.hud() checks contextvar first, falls back to instance callback - 15/15 engine tests green (4 new Phase 2 tests pass) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>