plan.md

Chess Emotions App - Plan

My Understanding

You want a chess app where:

1. You play chess in the browser against Stockfish
2. Reachy Mini reacts with emotions based on how good/bad your moves are

The fun twist: Reachy is "rooting for" Stockfish (the computer), so when you make a bad move, Reachy is happy - and when you make a good move, Reachy gets nervous or upset!

Technical Approach

Architecture

┌─────────────────────────────────────────────────────┐
│                    Browser (static/)                │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐  │
│  │ Chess Board │  │ Stockfish   │  │  Emotion    │  │
│  │ (chessboard │  │   (WASM)    │  │  Trigger    │  │
│  │    .js)     │  │             │  │  (to REST)  │  │
│  └─────────────┘  └─────────────┘  └─────────────┘  │
└───────────────────────────┬─────────────────────────┘
                            │ REST API calls
                            ▼
┌─────────────────────────────────────────────────────┐
│              Reachy Mini Daemon (port 8000)         │
│   /api/move/play/recorded-move-dataset/{dataset}/  │
│                     {emotion}                       │
└─────────────────────────────────────────────────────┘

Components

1. Chess UI - Using chess.js + chessboard.js libraries (both run in browser)
2. Stockfish - Using stockfish.js (WebAssembly, runs entirely in browser)
3. Move Evaluation - Stockfish provides centipawn scores to evaluate moves
4. Emotion Mapping - Map evaluation changes to emotions via REST API

Emotion Mapping (Draft)

Move Quality	Eval Change	Reachy's Reaction
Brilliant!	User gains 200+ cp	fear1, scared1, anxiety1
Good move	User gains 50-200 cp	worried, uncomfortable1
OK move	-50 to +50 cp	attentive1, thoughtful1
Mistake	User loses 50-200 cp	cheerful1, enthusiastic2
Blunder!	User loses 200+ cp	laughing1, success1, dance1
User checkmates	Game over	sad2, furious1, rage1
Stockfish wins	Game over	enthusiastic1, dance2, proud3

Libraries (all browser-based, no backend needed)

• chess.js - Chess logic, move validation, game state
• chessboard.js - Interactive board UI
• stockfish.js - Stockfish WASM for move generation & evaluation

---

Questions

Q1: Reachy's allegiance?

Should Reachy root for Stockfish (funny) or for you (supportive)?

• [ x ] Stockfish - Reachy is happy when you blunder, sad when you play well (funnier!)
• You - Reachy cheers your good moves, sad when you blunder (supportive)

Q2: Stockfish difficulty?

Should Stockfish play at full strength or be adjustable?

• Full strength - Maximum pain, Reachy will be happy a lot
• [ x ] Adjustable - Slider to set ELO (e.g., 800-3000)
• Fixed weaker - Set to ~1500 ELO for casual play

Q3: Reaction frequency?

How often should Reachy react?

• [ x ] Every move - Constant reactions (might be chaotic)
• Significant moves only - Only react to mistakes/good moves (>50cp change)
• Dramatic moments - Only blunders, brilliant moves, and game end

Q4: Additional features?

Any extras you'd like?

• Move commentary - Brief text explaining why the move was good/bad
• [ x ] Sound effects - Reachy makes sounds with emotions --> Note that the emotions already have sounds when played !
• Game history - Show evaluation graph over time
• Hints - Button to ask Stockfish for a hint

---

Implementation - DONE!

How to Run

1. Make sure the Reachy Mini daemon is running (on port 8000)
2. Run the app:

   cd /home/remi/reachy_mini_apps/chess_emotions_app
   python -m chess_emotions_app.main
   

3. Open http://localhost:8042/static/index.html in your browser
4. Play chess! Reachy will react to every move.

What Was Implemented

• Web UI with chessboard.js (drag & drop pieces)
• Stockfish 16 WASM running in browser with adjustable ELO (800-2800)
• Live evaluation bar showing position advantage
• Emotion mapping based on centipawn changes:
  • Brilliant move (>200cp gain): Reachy gets scared/anxious
  • Good move (50-200cp): Reachy is uncomfortable
  • Neutral move: Reachy watches attentively
  • Mistake (-50 to -200cp): Reachy is cheerful
  • Blunder (>200cp loss): Reachy laughs and dances!
  • Game over: Rage if you win, celebration if Stockfish wins

Files

• static/index.html - Chess UI layout
• static/style.css - Dark theme styling
• static/main.js - Chess logic, Stockfish integration, emotion triggers
• main.py - Minimal Python wrapper (serves static files)