turul-mcp-protocol

Model Context Protocol (MCP) specification implementation - Current version alias for future-proofing.

Overview

turul-mcp-protocol is a version alias crate that re-exports the current stable version of the Model Context Protocol implementation. This provides future-proofing and consistency across the turul-mcp-framework ecosystem.

Currently aliases: turul-mcp-protocol-2025-06-18

Features

• ✅ Future-Proof API - Always points to the latest stable MCP specification
• ✅ Consistent Imports - Use turul_mcp_protocol:: throughout your codebase
• ✅ Seamless Upgrades - Protocol version changes only require updating this dependency
• ✅ Complete Re-export - All types, traits, and constants from the current version
• ✅ Zero Runtime Cost - Pure compile-time aliasing with no performance impact

Usage

Add this to your Cargo.toml:

[dependencies]
turul-mcp-protocol = "0.2.0"

Import Pattern

✅ ALWAYS use the alias:

use turul_mcp_protocol::{
    Tool, CallToolRequest, CallToolResult,
    Resource, ReadResourceRequest, ReadResourceResult,
    InitializeRequest, InitializeResult
};

❌ NEVER import the versioned crate directly:

// DON'T DO THIS
use turul_mcp_protocol_2025_06_18::{Tool, CallToolRequest};

Protocol Version Abstraction

Current Version Information

use turul_mcp_protocol::{CURRENT_VERSION, MCP_VERSION, McpVersion};

fn check_protocol_version() {
    println!("Current MCP version: {}", CURRENT_VERSION);  // "2025-06-18"
    println!("Protocol constant: {}", MCP_VERSION);        // "2025-06-18"
    
    let version = McpVersion::from_str(CURRENT_VERSION).unwrap();
    assert_eq!(version, McpVersion::V2025_06_18);
}

Feature Compatibility

use turul_mcp_protocol::McpVersion;

fn check_feature_support(version: McpVersion) -> bool {
    match version {
        McpVersion::V2024_11_05 => {
            // Basic MCP without Streamable HTTP
            false
        }
        McpVersion::V2025_03_26 => {
            // Streamable HTTP support
            true
        }
        McpVersion::V2025_06_18 => {
            // Full feature set with _meta, cursor, progressToken
            true
        }
    }
}

Complete API Re-export

All types and functionality from the current MCP specification are available:

Core Protocol Types

use turul_mcp_protocol::{
    // Version and capabilities
    McpVersion, ClientCapabilities, ServerCapabilities,
    Implementation,
    
    // Initialization
    InitializeRequest, InitializeResult,
    
    // Tools
    Tool, ToolSchema, CallToolRequest, CallToolResult,
    ListToolsRequest, ListToolsResult,
    
    // Resources  
    Resource, ReadResourceRequest, ReadResourceResult,
    ListResourcesRequest, ListResourcesResult,
    
    // Prompts
    Prompt, GetPromptRequest, GetPromptResult,
    ListPromptsRequest, ListPromptsResult,
    
    // Sampling
    CreateMessageRequest, CreateMessageResult,
    
    // Notifications
    ProgressNotification, LoggingMessageNotification,
    ResourceUpdatedNotification, ResourceListChangedNotification,
};

Error Types

use turul_mcp_protocol::McpError;

fn handle_mcp_error(error: McpError) {
    match error {
        McpError::ToolNotFound(name) => println!("Tool not found: {}", name),
        McpError::ResourceNotFound(uri) => println!("Resource not found: {}", uri),
        McpError::InvalidParameters(msg) => println!("Invalid parameters: {}", msg),
        McpError::ToolExecutionError(msg) => println!("Tool execution failed: {}", msg),
        _ => println!("MCP error: {}", error),
    }
}

Trait System

use turul_mcp_protocol::{
    // Tool traits
    HasBaseMetadata, HasDescription, HasInputSchema, HasOutputSchema,
    ToolDefinition,
    
    // Resource traits
    HasResourceMetadata, ResourceDefinition, McpResource,
    
    // Request/Response traits
    HasMethod, HasParams,
    HasData, HasMeta,
};

// Example implementation
struct MyTool {
    name: String,
    description: String,
}

impl HasBaseMetadata for MyTool {
    fn name(&self) -> &str { &self.name }
}

impl HasDescription for MyTool {
    fn description(&self) -> Option<&str> { Some(&self.description) }
}

Framework Integration

Server Integration

The protocol types integrate seamlessly with turul-mcp-server to build a complete server. The following is a complete, runnable example.

Dependencies:

[dependencies]
turul-mcp-protocol = "0.2.0"
turul-mcp-server = "0.2.0"
turul-mcp-derive = "0.2.0"
tokio = { version = "1.0", features = ["full"] }

Example:

use turul_mcp_server::prelude::*;
use turul_mcp_derive::mcp_tool;

#[mcp_tool(name = "my_tool", description = "An example tool")]
async fn my_tool(#[param(description = "A message to echo")] message: String) -> McpResult<String> {
    Ok(format!("You said: {}", message))
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let server = McpServer::builder()
        .name("My MCP Server")
        .version("1.0.0")
        .tool_fn(my_tool)
        .bind_address("127.0.0.1:8080".parse()?)
        .build()?;

    println!("Server listening on http://127.0.0.1:8080");
    server.run().await?;
    Ok(())
}

Client Integration

use turul_mcp_protocol::{InitializeRequest, CallToolRequest};
use turul_mcp_client::{McpClient, McpClientBuilder, transport::HttpTransport};

let transport = HttpTransport::new("http://localhost:8080/mcp")?;
let client = McpClientBuilder::new()
    .with_transport(Box::new(transport))
    .build();

// Protocol types work directly with client methods
let tools = client.list_tools().await?;
let result = client.call_tool("my_tool", args).await?;

Version Migration Guide

Future Protocol Updates

When a new MCP protocol version is released, upgrading is seamless:

// Your code stays the same
use turul_mcp_protocol::{Tool, CallToolRequest, CallToolResult};

// Only the dependency version changes in Cargo.toml:
// [dependencies]
// turul-mcp-protocol = "0.2"  # Now points to MCP 2026-XX-XX

Handling Version-Specific Features

use turul_mcp_protocol::{McpVersion, CURRENT_VERSION};

fn use_version_specific_feature() {
    let current_version = McpVersion::from_str(CURRENT_VERSION).unwrap();
    
    match current_version {
        McpVersion::V2025_06_18 => {
            // Use current features like _meta support
            println!("Using MCP 2025-06-18 features");
        }
        // Future versions would be handled here
        _ => {
            println!("Using features from version: {}", CURRENT_VERSION);
        }
    }
}

Testing

The alias crate includes comprehensive tests to ensure re-exports work correctly:

# Test that all re-exports are functional
cargo test --package turul-mcp-protocol

# Test version consistency
cargo test --package turul-mcp-protocol test_current_version

# Test protocol parsing
cargo test --package turul-mcp-protocol test_version_parsing

Version Testing

#[cfg(test)]
mod tests {
    use turul_mcp_protocol::*;

    #[test]
    fn test_protocol_compatibility() {
        // Test that basic protocol types work
        let implementation = Implementation::new("test", "1.0.0");
        assert_eq!(implementation.name(), "test");
        
        let capabilities = ClientCapabilities::default();
        assert!(capabilities.roots.is_none());
        
        // Test version constants
        assert_eq!(CURRENT_VERSION, "2025-06-18");
        assert_eq!(MCP_VERSION, "2025-06-18");
    }
    
    #[test]
    fn test_all_major_types_available() {
        // Ensure all major protocol types are accessible
        let _tool = Tool::new("test", ToolSchema::object());
        let _resource = Resource::new("file:///test", "Test resource");
        let _prompt = Prompt::new("test");
        
        // If this compiles, re-exports are working
        assert!(true);
    }
}

Architecture Decision Record

Why Use a Version Alias?

Decision: Create turul-mcp-protocol as an alias to the current MCP specification version.

Rationale:

1. Future-Proofing: Applications can upgrade MCP versions by changing one dependency
2. Consistent Imports: All framework code uses turul_mcp_protocol:: imports
3. Clear Separation: Framework code vs specific protocol version implementation
4. Gradual Migration: New protocol versions can be adopted incrementally

Implementation:

• turul-mcp-protocol re-exports the current stable version
• All framework crates use the alias for imports
• Versioned crates contain actual protocol implementations
• Migration path is clear and documented

Feature Flags

[dependencies]
turul-mcp-protocol = { version = "0.2.0", features = ["server"] }

Available features:

• default - Core protocol types and traits
• server - Server-specific functionality and traits
• client - Client-specific functionality and helpers

These features are passed through to the underlying protocol implementation.

Contributing

When contributing to the framework:

1. Always use the alias: Import from turul_mcp_protocol, not the versioned crate
2. Update documentation: When the alias points to a new version, update examples
3. Test compatibility: Ensure changes work with the aliased version
4. Version consistency: Keep the alias pointing to the latest stable version

License

Licensed under the MIT License. See LICENSE for details.