LegalMiniUCI is a simple, single-file chess engine written in C, designed to support the UCI (Universal Chess Interface) protocol. It features iterative deepening, alpha-beta pruning, and basic evaluation with material and positional heuristics.

Note: This engine is still in development. Features, evaluation, and performance may change as the project evolves.

• Singe-file C implementation
• Supports UCI protocol
• Iterative deepening up to user-defined depth.
• Alpha-beta pruning for efficient search
• Simple evaluation with:
  • Material values
  • Piece-square tables(PSTs)
  • Mobility and positional considerations
• PV (principal variation) printing in UCI style
• Cross-platform: works on Windows, Linux, macOS
• Configurable search depth

You can compile manually using your VS Code terminal or any C compiler:

# Using GCC (on Linux / macOS)
gcc -O2 -Wall -Wextra -std=c11 legalminiuci.c -o legalminiuci.exe

# Using MinGW on Windows
gcc -O2 -Wall -Wextra -std=c11 legalminiuci.c -o legalminiuci.exe

For debugging, you can add -go O0 instead of -O2

./legalminiuci.exe   # Linux/macOS
legalminiuci.exe     # Windows

Then connect it to any UCI-compatible GUI like Arena, Cute Chess, or ChessGUI.

• uci – Initialize UCI mode
• isready – Engine readiness check
• ucinewgame – Start a new game
• position [fen ...] moves ... – Set position and moves
• go [depth ...] [nodes ...] [movetime ...] [wtime ...] [btime ...] – Start search
• quit – Exit the engine

uci
isready
ucinewgame
position startpos moves e2e4 e7e5
go depth 5

• Depth 5 works smoothly for normal hardware.
• Engine is single-threaded and designed for simplicity and education.
• For VS Code users, just open the terminal in the folder with legalminiuci.c and run the GCC command above.