gamecode-mcp2

A minimal, auditable Model Context Protocol (MCP) server for safe LLM-to-system interaction.

Overview

gamecode-mcp2 implements the Model Context Protocol specification, enabling Large Language Models to execute tools and interact with systems in a controlled, secure manner. It prioritizes security and auditability through explicit configuration and minimal dependencies.

Key Features

Security-first design: No dynamic code execution, only explicitly configured tools
Minimal dependencies: Pure JSON-RPC 2.0 over stdio
Explicit configuration: All tools defined in YAML with clear permissions
Auditable: Simple codebase designed for security review
Least-privilege alternatives: Replace risky MCP tools with safer, more restricted versions

Installation

cargo install gamecode-mcp2

Quick Start

Create a tools.yaml file:

tools:
  - name: read_file
    description: Read the contents of a file
    command: cat
    args:
      - name: path
        description: Path to the file to read
        required: true
        type: string
        cli_flag: null  # Positional argument

Run the server:

gamecode-mcp2

Configure your MCP client (e.g., Claude Desktop):

{
  "mcpServers": {
    "gamecode": {
      "command": "/path/to/gamecode-mcp2"
    }
  }
}

Tool Configuration

Tools are defined in YAML with the following structure:

tools:
  - name: tool_name
    description: What this tool does
    command: command_to_execute  # or "internal" for built-in handlers
    args:
      - name: argument_name
        description: What this argument is for
        required: true
        type: string  # string, number, boolean, or array
        cli_flag: --flag  # optional, null for positional args
        is_path: true  # optional, enables path validation
    validation:  # optional
      validate_paths: true
      allow_absolute_paths: false

Built-in Handlers

The server includes safe implementations of common operations:

add, multiply: Basic arithmetic
list_files: List directory contents
write_file: Write content to files (with validation)

Tool Loading Order

The server looks for tools in this order:

Command-line flag: --tools-file
Environment variable: GAMECODE_TOOLS_FILE
Local tools.yaml in current directory
Auto-detection based on project type
Config directory: ~/.config/gamecode-mcp/tools.yaml

Examples

See the examples/ directory for tool configurations for various use cases:

core/: Basic file and system operations
development/: Language-specific development tools
security/: Security-focused configurations
data/: Data processing tools

Security Considerations

Create least-privilege versions of risky tools by disabling other MCP servers and defining safer alternatives here
Commands are executed directly without shell interpretation
Optional path validation prevents directory traversal
All operations are logged to stderr for auditing
Single-threaded processing ensures predictable behavior
No dynamic code evaluation - all tools must be explicitly configured

License

MIT License - see LICENSE file for details

gamecode-mcp2 0.6.3