# BRIEFING — 2026-10-01T02:44:35Z

## Mission
Investigate existing implementation and test requirements for Milestone 2 Combat Feel Engine (`combat_feel_engine.js`), covering micro hit-stop, directional camera shake, and static ring buffer damage numbers.

## 🔒 My Identity
- Archetype: explorer
- Roles: investigator, synthesizer
- Working directory: c:\Projects\FreeExile\.agents\teamwork\explorer_m2_2_gen3
- Original parent: 77cd448f-be37-473e-809c-59db9f78e386
- Milestone: Milestone 2 (Character Animation & Visceral Combat Feel Engine)

## 🔒 Key Constraints
- Read-only investigation — do NOT implement
- Scope limited to `combat_feel_engine.js`, micro hit-stop, camera shake, and damage number ring buffer
- Line length cap: <= 350 soft / <= 500 hard
- Zero allocation in hot paths (120 FPS ProMotion budget, 8.33ms/frame)

## Current Parent
- Conversation ID: 77cd448f-be37-473e-809c-59db9f78e386
- Updated: 2026-10-01T02:44:35Z

## Investigation State
- **Explored paths**:
  - `c:\Projects\FreeExile\.agents\teamwork\ORIGINAL_REQUEST.md` (§2026-10-01T00:31:10Z §R2)
  - `c:\Projects\FreeExile\.agents\teamwork\orchestrator_3\SCOPE.md` (Features 7, 16, 19, 20)
  - `c:\Projects\FreeExile\PROJECT.md` (Milestone 2 specs)
  - `client/webapp/js/engine/combat_feel_engine.js` (Class implementation, 198 lines)
  - `client/webapp/js/engine/animation_engine.js` (hitStopTimer & isHitStopped animation pausing)
  - `client/webapp/js/data/weapon_swing_catalog.js` (Archetype hitStop frame specs: 2-4 frames / 33-66ms)
  - `client/webapp/js/engine/canvas_renderer.js` (Game render loop, camera shake integration)
  - `client/webapp/js/engine/combat_skills.js` (hitMonster attack resolution)
  - `client/webapp/js/engine/iso_math.js` (Legacy screenShake and damageTexts definitions)
  - `client/webapp/js/engine/vfx_renderer.js` (Legacy damageTexts array iteration)
  - `tests/e2e/test_poe2_ui_animation_vfx_e2e.py` (E2E tests f07, f16, boundary & cross tests)
  - `tools/lint/check_code_and_doc_hygiene.py` (Strict hygiene gate verification)
- **Key findings**:
  - `combat_feel_engine.js` exists (198 lines) but is partially orphaned: `update(dt)` and `renderDamageNumbers(ctx)` are not wired to `canvas_renderer.js`.
  - `isHitStopped(dt)` has a critical edge-case bug: calling `isHitStopped()` with no argument results in `this.hitStopTimer -= undefined` -> `NaN`, permanently disabling hit-stop.
  - Normal hit bounce scale in `combat_feel_engine.js` was initialized at 1.4->1.0 instead of the specified 1.6->1.0 pop-in bounce.
  - Screen shake intensity and duration lack strict clamping to the specified ranges (intensity 2.5-8.5, duration 0.12-0.45s) and directional attack angle bias.
  - Legacy `spawnDamageText` in `iso_math.js` and `vfx_renderer.js` still allocates objects dynamically via `damageTexts.push` and `splice`, violating zero-allocation hot path principles.
- **Unexplored areas**:
  - Server-side hit confirmation (client-authoritative feel for local feedback, server-authoritative damage validation in `CombatEngine`).

## Key Decisions Made
- Confirmed that `combat_feel_engine.js` satisfies line length limits (198 lines < 350 soft cap).
- Designed exact mathematical formulas and safety guards for hit-stop, directional camera shake matrix, and 64-slot RingBuffer pop-in bounce scale ($1.6 \rightarrow 1.0$).
- Outlined a concrete 4-step implementation and verification strategy for the worker subagent.

## Artifact Index
- `handoff.md` — Final structured handoff report
- `progress.md` — Liveness heartbeat
- `DISPATCH.md` — Incoming dispatch archive