HotRepl

Runtime C# REPL and typed command bridge for Unity games

Embed in any Unity game via BepInEx or MelonLoader. Inspect and automate a running game from your terminal, scripts, or AI agents — without rebuilding.

Raw Eval

Write C# on the game's main thread. Inspect live objects, run one-off repair snippets, explore the runtime interactively.

Typed Commands

Schema-validated operations registered by the host. Stable contract for repeatable exports, tests, and agent workflows.

Agent & MCP Ready

Connect via WebSocket SDK, CLI, or the nine-tool MCP stdio server. Plug into any coding agent, script, or automation pipeline.

Quickstart

import { connect } from "@hotrepl/sdk";

const session = await connect(); // ws://127.0.0.1:18590 by default
const name = await session.eval("UnityEngine.Application.productName");
const preflight = await session.run("archive.preflight", {});

console.log(name.value, preflight.output);

Integration paths

PathUse forEntry
Raw evalInteractive inspection, one-off repairsession.eval() / hotrepl eval
Typed commandsAutomation, exports, repeatable testssession.run() / command_call
CLIShell scripts, local workflows@hotrepl/cli
MCPAI agent tool catalog@hotrepl/mcp
Host embeddingNew loader adapters, test hostsIReplHost + ReplEngine.Tick()

Real consumers