suaveplan/openspec/changes/enterprise-gaming-vehicle-physics/tasks.md

Tasks: enterprise-gaming-vehicle-physics

0. Pre-flight (non-negotiable)

• 0.1 Confirm clean working tree (git status reports nothing) and no in-flight worktrees with uncommitted work (git worktree list then git status in each)
• 0.2 If any worktrees exist under .claude/worktrees/, account for each one: still-active agent, work-pending-merge, or stale-and-prune. Stale worktrees MUST be removed (git worktree remove) before opening a new one — code that has been lost twice on main is the failure mode this guards against.
• 0.3 Confirm the package set in MANIFEST.md matches find packages -maxdepth 3 -name package.json count. Drift here means a prior change archived without regenerating the manifest.

Phase 1 — Scaffold

• Create gaming/rigs/vehicle-physics/ (@suaveplan/vehicle-physics, 0.1.0, sideEffects: false)
• tsconfig.json, vitest.config.ts

Phase 2 — Error codes & constants

• src/error-codes.ts + src/constants/index.ts (air density, default torque curve, shift thresholds)

Phase 3 — Types

• src/types/common.ts + common.md

Phase 4 — Pacejka tire model

• src/models/pacejka/pacejka.ts — lateral force + longitudinal force from slip angle/ratio + BCDE coefficients
• Tests: symmetry at zero slip, force direction
• Docs

Phase 5 — Suspension

• src/models/suspension/suspension.ts — spring-damper PD controller per wheel, compression ratio
• Tests + docs

Phase 6 — Drivetrain

• src/models/drivetrain/drivetrain.ts — torque distribution FWD/RWD/AWD, gear ratio, differential slip, auto-shift
• Tests + docs

Phase 7 — Null backend

• src/backends/null-backend/null-backend.ts — flat infinite ground; all wheels grounded
• Tests + docs

Phase 8 — Vehicle

• src/core/vehicle/vehicle.ts — integrate all models per tick, OTel, events
• Tests + docs

Phase 9 — Property tests

• tests/property.test.ts — tire symmetry, suspension convergence, throttle → speed monotone

Phase 10 — Pre-publish gate

• bunx turbo lint typecheck test --filter=@suaveplan/vehicle-physics green
• 100% coverage
• Publish: bun scripts/publish.ts --package @suaveplan/vehicle-physics