Introduction

C# dotnet Universal Chess Interface wrapper for interacting with chess engine processes.

Getting started

Installation

You can install it with the Package Manager in your IDE or alternatively using the command line:

dotnet add package pax.uciChessEngine

Usage

The library now exposes a UciEngine that talks to a UCI-compatible binary and a small pooling helper in pax.uciChessEngine.EngineServices for safe reuse.

Quick start (single engine)

using pax.uciChessEngine;

await using var engine = new UciEngine(@"path\to\engine.binary");
await engine.StartAsync();
await engine.SetOption("Threads", 4);
await engine.SendAsync("ucinewgame", CancellationToken.None);
var bestMove = await engine.GetBestMoveAsync("1r1qr2k/p1n2p2/b1np1Np1/2p5/8/2NPB1PP/Pb1Q2B1/4RRK1 w - - 2 21", TimeSpan.FromSeconds(2));
Console.WriteLine($"Best move: {bestMove}");

Pooled usage (multiple consumers)

using pax.uciChessEngine;
using pax.uciChessEngine.EngineServices;

var options = new EngineRunOptions
{
    BinaryPath = @"path\to\engine.exe",
    PoolSize = 2,
    Threads = 4,
    Pvs = 2,
    HashMb = 256
};

var provider = EngineService.GetEngineSessionProvider(options);

await using var lease = await provider.AcquireAsync(CancellationToken.None);
var evals = await lease.Session.UseAsync(
    engine => EngineService.GetEvaluation(
        fen: "startpos",
        sideToMove: pax.chess.PieceColor.White,
        thinkTime: TimeSpan.FromMilliseconds(300),
        engine: engine,
        token: CancellationToken.None),
    CancellationToken.None);

Console.WriteLine($"Depth: {evals[0].Depth}, Score: {evals[0].Score}");

Migration from v0.6.* to v0.7

v0.7 is a breaking API refresh and targets .NET 10. Projects using v0.6.* on .NET 8 should update their target framework before upgrading the package.

The old Engine type has been replaced by UciEngine:

// v0.6.*
using var engine = new Engine("Stockfish", @"path\to\engine.exe");
await engine.Start();
await engine.IsReady();
await engine.SetOption("Threads", 4);
await engine.Send("ucinewgame");
await engine.Send("go");
await Task.Delay(2000);
await engine.Send("stop");
var info = engine.GetInfo();

// v0.7
await using var engine = new UciEngine(@"path\to\engine.exe");
await engine.StartAsync();
await engine.SetOption("Threads", 4);
var bestMove = await engine.GetBestMoveAsync(
    "1r1qr2k/p1n2p2/b1np1Np1/2p5/8/2NPB1PP/Pb1Q2B1/4RRK1 w - - 2 21",
    TimeSpan.FromSeconds(2));

Main changes:

• Replace Engine with UciEngine; the engine name constructor argument and LogLevel overload are no longer part of the public entry point.
• Use async lifecycle methods: StartAsync, SendAsync, StopAsync, and await using/DisposeAsync.
• StartAsync performs the UCI handshake, so callers usually do not need separate GetOptions() or IsReady() calls.
• Read engine options from engine.Status.EngineOptions instead of Status.Options.
• Read engine state from engine.Status.EngineState instead of Status.State.
• BestMove and Ponder are now UCI move strings (string?) instead of EngineMove values.
• For one-shot searches, prefer GetBestMoveAsync(fen, thinkTime, token) instead of manually sending position, go, waiting, and sending stop.
• For repeated analysis or concurrent consumers, use pax.uciChessEngine.EngineServices.EngineService.GetEngineSessionProvider(...) with EngineRunOptions so engine processes are reused instead of repeatedly started and disposed.

Sample Project pax.BlazorChess

ChangeLog

v0.7.0

• ** Breaking Changes **
• Update to dotnet 10

• UciEngine usability refreshed with async API.
• Engine pooling

v0.6.1

• ** Breaking Changes **
• Update to dotnet 8
• Logging disabled by default. Enable it with: Engine engine = new Engine("EngineName", @"path\to\engine\binary", LogLevel.Warning);