# HyperTwist Phase I-D reactive session-state environment cues preparation packet

Date: `2026-05-31`

## Goal

Reopen the landed `Phase I-A` through `Phase I-C` immersive lane one bounded
step further through explicit first-party reactive environment cues.

## Why this slice is justified

After `Phase I-C`, the immersive lane still lacked the careful feedback surfaces
promised by the roadmap scaffold:

- subtle transitions for review, mastery, correction, or failure states
- pacing-aware lighting shifts
- pacing-aware audio shifts
- challenge-mode versus study-mode differentiation

Those are the pieces that make the immersive lane responsive to training state
without becoming theatrical or distracting.

## Bounded implementation target

Land the first reactive-cue packet only:

- first-party session-state cue contract
- first-party lighting-reaction boundary
- first-party audio-pacing boundary
- first-party mode-differentiation contract
- runtime-library accessors for all four surfaces
- focused automation coverage

## Explicit non-goals

Do not widen this packet into:

- generic VFX ownership
- broad soundtrack scoring ownership
- cross-product mode framework ownership
- cinematic spectacle transitions
- later immersive hardening work like performance budgets or reduced-effects fallback

## Files expected to move

- `UnrealHyperTwist/Source/UnrealHyperTwist/Public/HyperTwistTraining/HyperTwistTrainingImmersiveEnvironmentLibrary.h`
- `UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistTraining/HyperTwistTrainingImmersiveEnvironmentLibrary.cpp`
- `UnrealHyperTwist/Source/UnrealHyperTwist/Public/HyperTwistTraining/HyperTwistTrainingRuntimeLibrary.h`
- `UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistTraining/HyperTwistTrainingRuntimeLibrary.cpp`
- `UnrealHyperTwist/Source/UnrealHyperTwist/Tests/HyperTwistImmersivePhaseIDReactiveCueContractTest.cpp`
- canon sync docs

## Validation target

Safe source-level validation only on this VPS:

- focused contract coverage for the new reactive state, lighting, audio, and mode-differentiation surfaces
- targeted wiring sweep
- `git diff --check`
