# BRIEFING — 2026-10-03T08:41:00Z

## Mission
Adversarially stress-test Cocos kinematics (zero-residual momentum frame 0, wall-sliding corner traps, A* extreme obstacles, dodge i-frame interrupts, boss gate thresholds) with empirical verification.

## 🔒 My Identity
- Archetype: challenger
- Roles: critic, specialist
- Working directory: c:\Projects\FreeExile\.agents\teamwork\challenger_kinematics_stress
- Original parent: cecb05d6-3b1b-4c90-84e7-b52ac4e7697c
- Milestone: M_CHALLENGE
- Instance: 1 of 1

## 🔒 Key Constraints
- Review-only — do NOT modify implementation code
- Write and execute empirical test harnesses; do NOT trust unverified claims or logs
- Must reproduce any bugs empirically
- Deliver handoff.md with explicit verdict (APPROVE or REQUEST_CHANGES) and notify parent

## Current Parent
- Conversation ID: cecb05d6-3b1b-4c90-84e7-b52ac4e7697c
- Updated: not yet

## Review Scope
- **Files reviewed**: 
  - `client/cocos/assets/scripts/core/KinematicsEngine.ts`
  - `client/cocos/assets/scripts/core/WallSliding.ts`
  - `client/cocos/assets/scripts/core/AStarPathfinder.ts`
  - `client/cocos/assets/scripts/combat/CombatController.ts`
  - `client/cocos/assets/scripts/combat/CombatFeel.ts`
  - `client/cocos/assets/scripts/animation/AnimationFSM.ts`
  - `client/cocos/assets/scripts/world/BossGateController.ts`
  - `client/cocos/assets/scripts/world/DungeonWorld.ts`
- **Interface contracts**: `PROJECT.md`, `ORIGINAL_REQUEST.md`
- **Review criteria**: Zero-residual momentum, wall sliding under acute/concave corners, A* under extreme obstacles, dodge i-frame combo interruption, boss gate pack threshold gating

## Key Decisions Made
- Executed direct empirical TypeScript testing via `npx tsx tests/unit/test_challenger_cocos_kinematics_stress.ts`.
- Evaluated 27 distinct adversarial edge checks.
- Discovered 2 HIGH and 3 MEDIUM severity bugs in `AStarPathfinder.ts`, `KinematicsEngine.ts`, and `AnimationFSM.ts`.
- Verdict: **REQUEST_CHANGES** due to diagonal wall corner-cutting in pathfinding and velocity telemetry zeroing in kinematics.

## Artifact Index
- `BRIEFING.md` — persistent situational awareness
- `progress.md` — execution progress
- `tests/unit/test_challenger_cocos_kinematics_stress.ts` — empirical stress test harness (27 checks)
- `handoff.md` — final assessment with 5-component handoff report

## Attack Surface
- **Hypotheses tested**: 
  1. Does zero-residual momentum in frame 0 hold without float drift? -> CONFIRMED PASS.
  2. Does wall-sliding prevent clipping in acute 45°, 90°, and concave corners? -> CONFIRMED PASS.
  3. Does A* pathfinding respect diagonal corner-touching walls? -> FAILED (LoS shortcuts through touching corners).
  4. Does A* LoS handle distances > 120 tiles safely? -> FAILED (returns true on loop exhaustion).
  5. Does rapid dodge cancel attack combo into 0.25s i-frame? -> CONFIRMED PASS.
  6. Does boss gate maintain impassable state at 2 kills and unlock at 3 kills? -> CONFIRMED PASS.
  7. Is velocity correctly computed during kinematics movement? -> FAILED (`velX` and `velY` are always 0.0 due to order-of-operations bug).
- **Vulnerabilities found**: 
  - `AStarPathfinder.ts:32-71`: Bresenham LoS lacks diagonal corner-pinch checks (HIGH).
  - `AStarPathfinder.ts:85`: LoS shortcut bypasses pathfinder and cuts corners (HIGH).
  - `AStarPathfinder.ts:70`: Step-limit bail-out returns `true` (MEDIUM).
  - `KinematicsEngine.ts:114-117`: `velX` and `velY` always evaluate to 0 during movement (MEDIUM).
  - `AnimationFSM.ts:83`: Single-frame advance per tick causes lag desync under frame drops (MEDIUM).
- **Untested angles**: None within kinematics and combat scope.

## Loaded Skills
- None