MCPInvoke 1.3.3

MCPInvoke

MCPInvoke is a complete Model Context Protocol (MCP) server implementation for ASP.NET Core applications. Originally designed as a companion to MCPBuckle for tool execution, MCPInvoke now provides full MCP protocol support including tool discovery and execution.

Purpose

This library enables ASP.NET Core applications with existing REST APIs and Swagger/OpenAPI documentation to easily become MCP-enabled. It provides a complete MCP server implementation that handles both tool discovery and execution, making your APIs accessible to AI agents and tools like Claude Code CLI.

Features

• Attribute-Driven (Optional, Extensible) - Leverages existing OpenAPI/Swagger metadata by default, with optional MCP-specific attributes for customization
• Standard-Compliant - Implements JSON-RPC 2.0 and MCP specifications
• Developer-Friendly - Minimal friction for projects already using Swagger/OpenAPI
• Secure - Input validation, sanitized outputs, and support for human-in-the-loop confirmations

What's New in 1.3.3

• Claude Code CLI Content Schema Fix - Fixed critical MCP response format to comply with Claude Code CLI content schema requirements
• MCP Content Format Compliance - All tool responses now properly formatted as {"content": [{"type": "text", "text": "json_data"}]}
• Full Claude Code CLI Compatibility - MCPInvoke now works seamlessly with Claude Code CLI and other MCP clients expecting content schema format

What's New in 1.3.2

• Critical Complex Object Fix - Fixed major bug where complex objects like BusinessProcessRequest failed with JsonElement conversion errors
• Enhanced Test Coverage - Added 6 new test methods specifically for complex object deserialization scenarios
• Improved Error Handling - Better error messages and logging for complex object deserialization failures

What's New in 1.3.1

• Aligned with MCPBuckle 1.5.1 - Updated to use the latest MCPBuckle version
• Added Comprehensive Test Suite - First test suite with 53 tests covering all functionality

What's New in 1.3.0

• Full MCP Protocol Support - MCPInvoke now implements the complete MCP protocol specification:
  • initialize - Returns server capabilities with protocol version 2025-06-18
  • notifications/initialized - Acknowledges client initialization
  • tools/list - Returns the list of available tools with proper JSON Schema
  • tools/call - Executes tool methods (existing functionality)
• Claude Code CLI Integration - Fully compatible with Anthropic's Claude Code CLI
• JSON Schema Compliance - Fixed schema generation to comply with JSON Schema draft 2020-12
• Improved Error Handling - Better error messages and protocol-compliant error responses

What's New in 1.2.0

• Enhanced API Response Handling - Improved handling of complex ASP.NET Core return types including ActionResult<T>, ObjectResult, and other IActionResult implementations
• MCPBuckle 1.5.0 Integration - Updated to use MCPBuckle 1.5.0 with enhanced schema generation, better parameter binding, and improved enum support
• Advanced Enum Support - Added full support for enum types, including both integer and string-based enums with JsonStringEnumConverter compatibility
• Collection Type Support - Better handling of array and collection return types for improved client compatibility
• New Middleware Architecture - Introduced dedicated McpInvokeMiddleware for more efficient request processing
• Simplified Configuration - Added ApplicationBuilderExtensions with UseMcpInvoke extension method for easier integration
• Parameter Annotations - Added support for additional parameter metadata through Annotations property

What's New in 1.1.0

• MCPBuckle 1.4.0 Integration - Updated to use the MCPBuckle 1.4.0 NuGet package for better MCP specification compliance
• Special JSON-RPC Method Handling - Added support for standard JSON-RPC methods:
  • notifications/initialized - Properly acknowledges initialization notifications from MCP clients
  • tools/list - Returns a helpful error message directing clients to use the MCP context endpoint instead

Getting Started

Installation

dotnet add package MCPInvoke

Basic Setup

// In Program.cs or Startup.cs
using MCPInvoke.Extensions;
using MCPInvoke.AspNetCore.Extensions;

// Register MCPInvoke services
builder.Services.AddMcpInvoke();

// Register an implementation of IMcpToolDefinitionProvider
// See below for ASP.NET Core controller integration

// Register endpoint using the middleware
app.UseMcpInvoke("/mcpinvoke");

ASP.NET Core Controller Integration

MCPInvoke provides automatic ASP.NET Core controller integration:

// In Program.cs or Startup.cs
using MCPInvoke.AspNetCore.Extensions;

// Register MCPInvoke with ASP.NET Core controller integration
builder.Services.AddMcpInvokeWithControllers(options => {
    // Include controller name in tool name
    options.IncludeControllerNameInToolName = true;
    
    // Optionally exclude specific controllers
    // options.ExcludedControllers.Add("Health");
});

// Use the MCP Invoke middleware
app.UseMcpInvoke("/mcpinvoke");

For more detailed information on ASP.NET Core integration, see the AspNetCore README.

Claude Code CLI Integration

MCPInvoke 1.3.0+ is fully compatible with Anthropic's Claude Code CLI. To integrate your API with Claude:

1. Configure your API with MCPInvoke:

   // In Program.cs
   builder.Services.AddMcpInvokeWithControllers();
   app.UseMcpInvoke("/mcpinvoke");
   

2. Add your API as an MCP server in Claude Code CLI:

   claude mcp add --transport http my-api http://localhost:5000/mcpinvoke
   

3. Use your API tools in Claude:

   echo "Use the mcp__my-api__ToolName to perform task X" | claude
   

Your API tools will be available with the prefix mcp__<server-name>__ in Claude Code CLI.

MCP Protocol Support

MCPInvoke implements the full MCP protocol specification:

The server supports protocol version 2025-06-18 and is compatible with all MCP-compliant clients.