MCP server for Minecraft mod configuration file management. Reads, validates, compares, and cleans up .cfg, .toml, and .json config files from modpacks.

Tools

Tool	Description
`read_mod_config`	Parse a single config file (`.cfg`, `.toml`, `.json`) and return structured data with any issues
`list_mod_configs`	Recursively scan a config directory and list all configs with mod ID, format, and size
`validate_mod_configs`	Validate all configs for common issues: empty values, invalid numbers, parse errors, oversized strings
`compare_mod_configs`	Diff two config directories (before/after modpack update) and report added/removed/changed files
`find_orphaned_configs`	Find config files whose mod JAR is no longer present in the `mods/` directory
`get_mod_default_config`	Return known default/baseline config for popular mods (Sodium, OptiFine, Phosphor, Lithium, Fabric API)

Supported Config Formats

Format	Extension	Loader
Forge INI-style	`.cfg`	Forge
Fabric TOML	`.toml`	Fabric
JSON	`.json`	Any

Features

Multi-format parsing — handles Forge .cfg, Fabric .toml, and .json configs natively
Validation engine — detects empty values, invalid numbers, parse errors, and oversized strings
Config comparison — key-level diff for tracking changes across modpack updates
Orphan detection — matches config files against installed mod JARs plus a built-in known-mods database
Default configs — bundled known-good defaults for popular performance mods
Fully offline — no network calls; all data is local or built-in

Installation

Prerequisites

Node.js 18+
npm

Build

cd mc-mod-config-mcp
npm install
npm run build

Run as standalone MCP server

node dist/index.js

The server communicates via stdio (JSON-RPC 2.0). It can be consumed by any MCP-compatible client.

Configuration for MCP clients

Add to your MCP client config:

{
  "mcpServers": {
    "mc-mod-config": {
      "command": "node",
      "args": ["${MC_MOD_CONFIG_ROOT}/dist/index.js"]
    }
  }
}

Path note: Replace ${MC_MOD_CONFIG_ROOT} with the absolute path to this project's root directory. On Windows, use forward slashes: ["C:/path/to/mc-mod-config-mcp/dist/index.js"]（把 C:/path/to/ 替换成你的实际路径）。 Alternatively, set an environment variable MC_MOD_CONFIG_ROOT pointing to the project root and use the variable in the config.

Configuration

本工具零配置即可用（内置默认值，任何环境开箱即用）。以下项目可通过环境变量或项目根目录 .env 文件覆盖（复制 .env.example 为 .env）：

变量	默认值	说明
`MOD_CONFIG_EXTENSIONS`	`cfg,toml,json`	支持扫描/解析的配置文件扩展名（逗号分隔，可扩展自定义扩展名）
`MOD_CONFIG_MAX_FILE_MB`	`50`	单个配置文件大小上限（MB），超过则跳过
`MOD_CONFIG_MAX_STRING_LEN`	`500`	校验时字符串值长度告警阈值

扩展已知模组默认配置库：编辑 src/mod-defaults.json（构建后为 dist/mod-defaults.json），在 defaults 下新增/覆盖模组即可，无需改代码。例如新增 "iris": { "name": "Iris", "fallbackConfig": { "enableShaders": true } }。

优先级：环境变量 > .env 文件 > 内置默认值。改动后重启 MCP server 生效。

Usage Examples

Read a config file

{
  "name": "read_mod_config",
  "arguments": {
    "configPath": "/path/to/mods/sodium/sodium.toml"
  }
}

List all configs in a modpack

{
  "name": "list_mod_configs",
  "arguments": {
    "configDir": "/path/to/modpack/config"
  }
}

Validate configs for issues

{
  "name": "validate_mod_configs",
  "arguments": {
    "configDir": "/path/to/modpack/config"
  }
}

Compare configs before and after an update

{
  "name": "compare_mod_configs",
  "arguments": {
    "oldConfigDir": "/path/to/old-modpack/config",
    "newConfigDir": "/path/to/new-modpack/config"
  }
}

Find orphaned configs

{
  "name": "find_orphaned_configs",
  "arguments": {
    "modsDir": "/path/to/modpack/mods",
    "configDir": "/path/to/modpack/config"
  }
}

Get default config for a mod

{
  "name": "get_mod_default_config",
  "arguments": {
    "modId": "sodium"
  }
}

Architecture

mc-mod-config-mcp/
├── src/
│   └── index.ts        # MCP server + all tool implementations
├── dist/               # Compiled JavaScript (output of tsc)
├── skills/
│   └── mc-mod-config-helper.md  # Trae Work skill for config management
├── __tests__/
│   └── unit.test.ts    # Unit tests (fully offline)
├── package.json        # Node.js dependencies (@modelcontextprotocol/sdk, zod)
├── tsconfig.json       # TypeScript config (CommonJS output)
└── .gitignore

The MCP uses the official @modelcontextprotocol/sdk v1.x with McpServer and StdioServerTransport.

Testing

npm run build
npm test

All unit tests are fully offline and do not require a Minecraft installation.

Platform Compatibility

Tool	Windows	macOS	Linux
`read_mod_config`	✅	✅	✅
`list_mod_configs`	✅	✅	✅
`validate_mod_configs`	✅	✅	✅
`compare_mod_configs`	✅	✅	✅
`find_orphaned_configs`	✅	✅	✅
`get_mod_default_config`	✅	✅	✅

All tools use cross-platform Node.js fs and path APIs. All paths are resolved as absolute paths before processing. The Forge .cfg parser handles sections, type detection, and quoted values; the Fabric .toml parser handles nested tables and arrays.