reeutils 1.6.0

🧩 reeutils, IntelOrca.Biohazard.REE

A .NET library for working with RE Engine resource formats and PAK files. Primarily developed to support the biorand project, but useful for modding most RE engine games.

🚀 Usage

Add the package to your project by referencing the NuGet package in your .csproj:

<PackageReference Include="IntelOrca.Biohazard.REE" Version="1.6.0" />

Basic example showing how to open a file from the game's patched pak files, modify it and write a new patch pak:

using IntelOrca.Biohazard.REE.Package;
using IntelOrca.Biohazard.REE.Rsz;

var repo = RszRepositorySerializer.Default.FromJsonFile(@"C:\reasy\rszre4.json");
using var pak = new RePakCollection(@"C:\Program Files (x86)\Steam\steamapps\common\RESIDENT EVIL 4  BIOHAZARD RE4");

// Get user data and create new modified version
const string guiParamPath = "natives/stm/_chainsaw/appsystem/ui/userdata/guiparamholdersettinguserdata.user.2";
var userFileBuilder = new UserFile(pak.GetEntryData(guiParamPath)).ToBuilder(repo);
var root = userFileBuilder.Objects[0];
root = root.Set("_InGameShopGuiParamHolder._HoldTime_Purchase", 0.1f);
userFileBuilder.Objects = [root];
var newUserFile = userFileBuilder.Build();

// Create new patch pak file with modified user file
var pakBuilder = new PakFileBuilder();
pakBuilder.AddEntry(guiParamPath, newUserFile.Data);
pakBuilder.Save("re_chunk_000.pak.patch_006.pak");

🤖 MCP server

reeutils also runs as a Model Context Protocol server, so AI coding assistants can browse, search and inspect game files for you. It exposes the CLI functionality as tools: open_pak, set_game, find, list_files, read, search, get_type, generate_class and get_engine_details, backed by embedded pak listings and RSZ type data for oniws, re2, re3, re4, re7, re8 and re9.

The server speaks stdio and requires the .NET 10 SDK, which provides dnx — the .NET equivalent of npx. No install step is needed, the client runs the published tool directly:

{
  "mcpServers": {
    "reeutils": {
      "command": "dnx",
      "args": ["reeutils", "mcp"]
    }
  }
}

Put this in your client's MCP configuration file, for example:

• Claude Code / Cursor: .mcp.json or .cursor/mcp.json, using the mcpServers key shown above.
• Claude Desktop: claude_desktop_config.json, also using mcpServers.
• VS Code: .vscode/mcp.json, which uses a top level servers key with "type": "stdio" alongside the same command and args.

By default the latest release is used. A version can be pinned the same way as with npx, either exactly ("args": ["reeutils@1.6.0", "mcp"]) or as a range ("args": ["reeutils@1.*", "mcp"]).

If you prefer a permanent install, run dotnet tool install --global reeutils and then use "command": "reeutils" with "args": ["mcp"] instead.

When developing reeutils itself, point the client at the local build:

{
  "mcpServers": {
    "reeutils": {
      "command": "dotnet",
      "args": ["run", "--project", "src/reeutils", "--", "mcp"]
    }
  }
}

A typical session starts with the assistant calling open_pak on a game install directory or .pak file, followed by set_game (e.g. re4), after which it can locate and read files without further setup.

📦 Build

• Requirements: .NET SDK 10.0.
• Build the solution:

dotnet build reeutils.sln

🧪 Tests

• Run tests with the dotnet test runner:

dotnet test

• Note: many tests require access to original game PAK files and RSZ type JSON dumps. You must configure local paths to where Resident Evil games are installed before running those tests.
  • By default the test helper test/IntelOrca.Biohazard.REE.Tests/OriginalPakHelper.cs contains example paths used on the author machine. Edit that file to point to your game installation directories or ensure equivalent paths exist on your machine.
  • The RSZ type JSON files used by tests are referenced from a local reasy clone in the tests (see GetTypeRepository in OriginalPakHelper.cs). Place or point those JSON dumps to the expected paths or update the test helper accordingly.

⚙️ Design

• The library is designed around immutability and builder patterns for thread-safety and efficient cloning. Builders provide explicit, safe mutation paths while core types remain immutable to allow safe sharing across threads and cheap copy-on-write style operations.

Supported formats (RE Engine)

Note: Onimusha .pog.12 point graphs (placed enemy/item/gimmick nodes, .poglst.0 lists, and .cset.6 collider sets) are fully read+write. .fsmv2.42 behaviour trees now support import for versions 30, 40, and 42 (RE2/RE3, RE8, and RE9/Onimusha-era).

Note: when invoking the CLI on versioned files, keep the version suffix (.19/.16/.30) — bare extensions default to the RT/newer versions.

🙏 Credits

• Thanks to the REasy project for RSZ JSON dumps and type information used in tests and tooling.
• Historical tooling and ideas inspired by RSZTool.
• Additional contributions and community tooling from Namsku.

🧾 License

This repository is MIT licensed.