FxKit MCP Server

A Model Context Protocol (MCP) server that provides comprehensive documentation and assistance for the FxKit C# functional programming library.

Overview

FxKit MCP dynamically fetches and serves documentation from the official FxKit documentation site, providing AI models with:

• Complete documentation for all FxKit types (Option, Result, Validation, Unit)
• Compiler services documentation (source generators, analyzers)
• Code examples and API references
• Search capabilities across all documentation
• Pre-built prompts for common FxKit patterns

Features

Resources

The server exposes FxKit documentation sections as MCP resources:

• introduction - FxKit overview and concepts
• getting-started - Installation and setup guide
• option - Option type documentation
• result - Result type documentation
• validation - Validation type documentation
• unit - Unit type documentation
• compiler-overview - Compiler services overview
• enum-match - EnumMatch generator
• union - Union type generator
• lambda - Lambda generator
• transformer - Transformer generator
• testing - Testing utilities

Tools

Interactive tools for querying FxKit documentation:

• search_documentation - Search across all documentation
• get_examples - Get code examples for specific features
• list_packages - List available NuGet packages

Prompts

Pre-configured prompts for common FxKit patterns:

• convert-nullable-to-option - Convert nullable types to Option
• railway-oriented-programming - Implement railway-oriented patterns
• validation-multiple-errors - Use Validation for error accumulation
• generate-union-types - Create union types with source generators

Installation

From Source

1. Clone this repository:

git clone https://github.com/taxfyle/fxkit-mcp.git
cd fxkit-mcp

1. Install dependencies:

npm install

1. Build the project:

npm run build

Global Installation

npm install -g @taxfyle/fxkit-mcp

Usage

With Claude Code

{
  "mcpServers": {
    "fxkit-docs": {
      "command": "npx",
      "args": [
        "-y",
        "@taxfyle/fxkit-mcp@latest"
      ],
      "env": {}
    }
  }
}

With Claude Desktop

Add the following to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "fxkit-docs": {
      "command": "node",
      "args": ["/path/to/fxkit-mcp/dist/index.js"]
    }
  }
}

Or if installed globally:

{
  "mcpServers": {
    "fxkit-docs": {
      "command": "fxkit-mcp"
    }
  }
}

With MCP Inspector

Test the server using the MCP Inspector:

npx @modelcontextprotocol/inspector tsx src/index.ts

Programmatic Usage

import { FxKitMcpServer } from 'fxkit-mcp';

const server = new FxKitMcpServer();
await server.start();

Development

Running in Development Mode

npm run dev

Project Structure

fxkit-mcp/
├── src/
│   ├── index.ts              # Main entry point
│   ├── server.ts              # MCP server implementation
│   ├── types.ts               # TypeScript type definitions
│   ├── fetcher/
│   │   └── docs-fetcher.ts    # Documentation fetching logic
│   ├── resources/             # Resource handlers (if extended)
│   ├── tools/                 # Tool implementations (if extended)
│   └── prompts/               # Prompt templates (if extended)
├── dist/                      # Compiled JavaScript
├── package.json
├── tsconfig.json
└── README.md

Testing

The server includes a test mode that verifies all documentation endpoints are accessible:

npm test

Examples

Using with an AI Assistant

Once configured, you can ask your AI assistant questions like:

• "Show me the FxKit documentation for the Result type"
• "Search for examples of railway-oriented programming with FxKit"
• "How do I convert nullable types to Option in FxKit?"
• "Generate a union type for payment methods using FxKit"

The AI will use the MCP server to fetch relevant documentation and provide accurate, up-to-date information about FxKit.

Architecture

The server uses a dynamic fetching approach:

1. No Static Content: Documentation is fetched on-demand from the live FxKit documentation site
2. Caching: Responses are cached for 5 minutes to improve performance
3. HTML Parsing: Uses Cheerio to extract content and code examples from documentation pages
4. Type Safety: Full TypeScript implementation with strict typing

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

Adding New Documentation Sections

To add new documentation sections:

1. Update the paths array in src/fetcher/docs-fetcher.ts
2. Add corresponding resource registration in src/server.ts
3. Test that the new section is accessible

Extending Tools

New tools can be added in src/server.ts in the setupTools() method. Follow the existing pattern using registerTool().

License

MIT

Acknowledgments

• FxKit - The functional programming library for C#
• Model Context Protocol - The protocol specification
• effect-mcp - Inspiration for MCP server structure

Support

For issues related to:

• FxKit library: Visit the FxKit GitHub repository
• This MCP server: Open an issue in this repository
• MCP protocol: Check the MCP documentation# fxkit-mcp