# js/physics/rules/ — agents.md
Part of the modularization pass. Module map: `MODULES.md`; runtime model: `architecture.md`.

Installs into `P`: checkEndStates, birdsRemaining, starsFor.

- Win/lose arbitration (called from step): all enemies dead -> won, no bird
  left in play with enemies alive -> lost. S-5 (added 2026-09-29):
  a LANDED bird counts as a bird still in play — do not declare `lost` while
  one is out in the world (it can still fall, smash and kill). `starsFor(g)`
  maps score to the level's three star thresholds.
- Keep this submodule free of physics: it decides, it does not move anything.