twisty

A partially-observable twisty puzzle environment exposed as MCP tools.

The cube is fixed in space. From any viewpoint you see exactly 3 of 6 faces — the other 3 are hidden. Rotate the camera to reveal new faces, apply moves to solve, and try to minimize total steps.

Quick start

Claude Code:

claude mcp add --transport stdio twisty -- uvx twisty

Codex CLI:

codex mcp add twisty -- uvx twisty

Claude Desktop / Cursor / VS Code — add to your MCP config:

{
  "mcpServers": {
    "twisty": {
      "type": "stdio",
      "command": "uvx",
      "args": ["twisty"]
    }
  }
}

Or commit .mcp.json to your repo for team sharing — Claude Code will auto-detect it.

How it works

This is a Partially Observable Markov Decision Process (POMDP). The agent interacts with a standard 3x3 cube through a constrained observation model:

• Fixed cube — the cube doesn't rotate; R always turns the Right face clockwise
• 8 viewpoints — 4 top-ring and 4 bottom-ring camera positions, each revealing 3 faces
• Partial observability — at any moment, 3 faces are visible and 3 are hidden
• Cost model — face turns cost 1 move step, camera rotations cost 1 inspection step
• Goal — solve the cube while minimizing total steps (moves + inspections)

A typical session: scramble() → look() → plan → move() / rotate_view() → repeat until is_solved() returns true.

Tools

Tool	Description	Cost
scramble(num_moves)	Scramble with n random moves (default 20)	—
look()	Read the current 3-face view	Free
rotate_view(direction)	Orbit camera: left, right, up, down	1 inspection
move(notation)	Apply a face turn: R, U', F2, L, D', B2, etc.	1 move
is_solved()	Check if the cube is solved	Free
get_history()	Moves applied since last scramble	Free
get_stats()	Moves, inspections, total steps, solved status	Free
reset()	Reset to solved state	—

What the model sees

Each tool call returns a net render of the cube — visible faces in color, hidden faces hatched out:

Front-Right-Top	Front-Left-Top	Front-Right-Bottom
Sees F, R, U	Sees F, L, U	Sees F, R, D

Live viewer

A browser-based 3D viewer launches automatically at localhost:4321 when the server starts. It shows:

• Animated cube state via cubing.js TwistyPlayer
• Camera synced to the agent's current viewpoint
• Viewpoint net highlighting visible faces
• Move and inspection counters
• Tool call history
• Picture-in-Picture mode for watching while the agent works in another window

Development

git clone https://github.com/tejadhith/cube.git
cd cube
uv sync
uv run cube-server

Built with

• magiccube — cube simulation
• cubing.js — 3D puzzle viewer
• MCP — Model Context Protocol SDK