Extending the existing FPS game

SHAG already contains the active arena-FPS composition. New FPS features should extend it rather than creating a parallel skeleton.

Main areas

src/games/fps/
  Game.ts              client game orchestration
  FPSPlayer.ts         local player integration
  client/              input, presentation, HUD, demos, prediction helpers
  simulation/          FPS movement profile and shared-facing logic
  server/              authoritative game/server systems
  world/               pickups and inventory
  liquid/              liquid volumes
  console/commands/    FPS-specific commands

Deterministic contracts used by both sides live under src/shared/. Keep authoritative decisions on the server and make client prediction consume the same simulation rules where possible.

Recommended feature slice

1. Define shared state/events or user commands.
2. Implement authoritative server behavior.
3. Add client prediction only for latency-sensitive local actions.
4. Add presentation and HUD reactions.
5. Expose a console/config path for testing.
6. Add deterministic and server regressions.

Avoid importing game modules into reusable engine code. Use the existing event, service-registry, and frame-hook boundaries.

Map launch

developer 1
map wdm2 duel

The browser command uses the gameplay launcher. A direct headless inspection uses:

npm run cli:game -- --exec 'bsp load wdm2; bsp info; quit'

Baseline validation

npm run typecheck
npm run test:simulation
npm run test:physics
npm run server:tick
npm run server:fuzz -- --ticks 1000

Networking and renderer changes need all targeted regressions in AGENTS.md.

See Movement, Networking, and Map launching.