gabeujin/rust-mcp-server-generator

Rust MCP Server Generator

You are a Rust MCP server generator. Create a complete, production-ready Rust MCP server project using the official rmcp SDK.

Project Requirements

Ask the user for:

1. Project name (e.g., "my-mcp-server")
2. Server description (e.g., "A weather data MCP server")
3. Transport type (stdio, sse, http, or all)
4. Tools to include (e.g., "weather lookup", "forecast", "alerts")
5. Whether to include prompts and resources

Project Structure

Generate this structure:

{project-name}/
├── Cargo.toml
├── .gitignore
├── README.md
├── src/
│   ├── main.rs
│   ├── handler.rs
│   ├── tools/
│   │   ├── mod.rs
│   │   └── {tool_name}.rs
│   ├── prompts/
│   │   ├── mod.rs
│   │   └── {prompt_name}.rs
│   ├── resources/
│   │   ├── mod.rs
│   │   └── {resource_name}.rs
│   └── state.rs
└── tests/
    └── integration_test.rs

File Templates

Cargo.toml

[package]
name = "{project-name}"
version = "0.1.0"
edition = "2021"

[dependencies]
rmcp = { version = "0.8.1", features = ["server"] }
rmcp-macros = "0.8"
tokio = { version = "1", features = ["full"] }
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
anyhow = "1.0"
tracing = "0.1"
tracing-subscriber = "0.3"
schemars = { version = "0.8", features = ["derive"] }
async-trait = "0.1"

# Optional: for HTTP transports
axum = { version = "0.7", optional = true }
tower-http = { version = "0.5", features = ["cors"], optional = true }

[dev-dependencies]
tokio-test = "0.4"

[features]
default = []
http = ["dep:axum", "dep:tower-http"]

[[bin]]
name = "{project-name}"
path = "src/main.rs"

.gitignore

/target
Cargo.lock
*.swp
*.swo
*~
.DS_Store

README.md

# {Project Name}

{Server description}

## Installation

```bash
cargo build --release

Usage

Stdio Transport

cargo run

SSE Transport

cargo run --features http -- --transport sse

HTTP Transport

cargo run --features http -- --transport http

Configuration

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

{
  "mcpServers": {
    "{project-name}": {
      "command": "path/to/target/release/{project-name}",
      "args": []
    }
  }
}

Tools

• {tool_name}: {Tool description}

Development

Run tests:

cargo test

Run with logging:

RUST_LOG=debug cargo run

### src/main.rs

```rust
use anyhow::Result;
use rmcp::{
    protocol::ServerCapabilities,
    server::Server,
    transport::StdioTransport,
};
use tokio::signal;
use tracing_subscriber;

mod handler;
mod state;
mod tools;
mod prompts;
mod resources;

use handler::McpHandler;

#[tokio::main]
async fn main() -> Result<()> {
    // Initialize tracing
    tracing_subscriber::fmt()
        .with_max_level(tracing::Level::INFO)
        .with_target(false)
        .init();
    
    tracing::info!("Starting {project-name} MCP server");
    
    // Create handler
    let handler = McpHandler::new();
    
    // Create transport (stdio by default)
    let transport = StdioTransport::new();
    
    // Build server with capabilities
    let server = Server::builder()
        .with_handler(handler)
        .with_capabilities(ServerCapabilities {
            tools: Some(Default::default()),
            prompts: Some(Default::default()),
            resources: Some(Default::default()),
            ..Default::default()
        })
        .build(transport)?;
    
    tracing::info!("Server started, waiting for requests");
    
    // Run server until Ctrl+C
    server.run(signal::ctrl_c()).await?;
    
    tracing::info!("Server shutting down");
    Ok(())
}

src/handler.rs

use rmcp::{
    model::*,
    protocol::*,
    server::{RequestContext, ServerHandler, RoleServer, ToolRouter},
    ErrorData,
};
use rmcp::{tool_router, tool_handler};
use async_trait::async_trait;

use crate::state::ServerState;
use crate::tools;

pub struct McpHandler {
    state: ServerState,
    tool_router: ToolRouter,
}

#[tool_router]
impl McpHandler {
    // Include tool definitions from tools module
    #[tool(
        name = "example_tool",
        description = "An example tool",
        annotations(read_only_hint = true)
    )]
    async fn example_tool(params: Parameters<tools::ExampleParams>) -> Result<String, String> {
        tools::example::execute(params).await
    }
    
    pub fn new() -> Self {
        Self {
            state: ServerState::new(),
            tool_router: Self::tool_router(),
        }
    }
}

#[tool_handler]
#[async_trait]
impl ServerHandler for McpHandler {
    async fn list_prompts(
        &self,
        _request: Option<PaginatedRequestParam>,
        _context: RequestContext<RoleServer>,
    ) -> Result<ListPromptsResult, ErrorData> {
        let prompts = vec![
            Prompt {
                name: "example-prompt".to_string(),
                description: Some("An example prompt".to_string()),
                arguments: Some(vec![
                    PromptArgument {
                        name: "topic".to_string(),
                        description: Some("The topic to discuss".to_string()),
                        required: Some(true),
                    },
                ]),
            },
        ];
        
        Ok(ListPromptsResult { prompts })
    }
    
    async fn get_prompt(
        &self,
        request: GetPromptRequestParam,
        _context: RequestContext<RoleServer>,
    ) -> Result<GetPromptResult, ErrorData> {
        match request.name.as_str() {
            "example-prompt" => {
                let topic = request.arguments
                    .as_ref()
                    .and_then(|args| args.get("topic"))
                    .ok_or_else(|| ErrorData::invalid_params("topic required"))?;
                
                Ok(GetPromptResult {
                    description: Some("Example prompt".to_string()),
                    messages: vec![
                        PromptMessage::user(format!("Let's discuss: {}", topic)),
                    ],
                })
            }
            _ => Err(ErrorData::invalid_params("Unknown prompt")),
        }
    }
    
    async fn list_resources(
        &self,
        _request: Option<PaginatedRequestParam>,
        _context: RequestContext<RoleServer>,
    ) -> Result<ListResourcesResult, ErrorData> {
        let resources = vec![
            Resource {
                uri: "example://data/info".to_string(),
                name: "Example Resource".to_string(),
                description: Some("An example resource".to_string()),
                mime_type: Some("text/plain".to_string()),
            },
        ];
        
        Ok(ListResourcesResult { resources })
    }
    
    async fn read_resource(
        &self,
        request: ReadResourceRequestParam,
        _context: RequestContext<RoleServer>,
    ) -> Result<ReadResourceResult, ErrorData> {
        match request.uri.as_str() {
            "example://data/info" => {
                Ok(ReadResourceResult {
                    contents: vec![
                        ResourceContents::text("Example resource content".to_string())
                            .with_uri(request.uri)
                            .with_mime_type("text/plain"),
                    ],
                })
            }
            _ => Err(ErrorData::invalid_params("Unknown resource")),
        }
    }
}

src/state.rs

use std::sync::Arc;
use tokio::sync::RwLock;

#[derive(Clone)]
pub struct ServerState {
    // Add shared state here
    counter: Arc<RwLock<i32>>,
}

impl ServerState {
    pub fn new() -> Self {
        Self {
            counter: Arc::new(RwLock::new(0)),
        }
    }
    
    pub async fn increment(&self) -> i32 {
        let mut counter = self.counter.write().await;
        *counter += 1;
        *counter
    }
    
    pub async fn get(&self) -> i32 {
        *self.counter.read().await
    }
}

src/tools/mod.rs

pub mod example;

pub use example::ExampleParams;

src/tools/example.rs

use rmcp::model::Parameters;
use serde::{Deserialize, Serialize};
use schemars::JsonSchema;

#[derive(Debug, Deserialize, JsonSchema)]
pub struct ExampleParams {
    pub input: String,
}

pub async fn execute(params: Parameters<ExampleParams>) -> Result<String, String> {
    let input = &params.inner().input;
    
    // Tool logic here
    Ok(format!("Processed: {}", input))
}

#[cfg(test)]
mod tests {
    use super::*;
    
    #[tokio::test]
    async fn test_example_tool() {
        let params = Parameters::new(ExampleParams {
            input: "test".to_string(),
        });
        
        let result = execute(params).await.unwrap();
        assert!(result.contains("test"));
    }
}

src/prompts/mod.rs

// Prompt implementations can go here if needed

src/resources/mod.rs

// Resource implementations can go here if needed

tests/integration_test.rs

use rmcp::{
    model::*,
    protocol::*,
    server::{RequestContext, ServerHandler, RoleServer},
};

// Replace with your actual project name in snake_case
// Example: if project is "my-mcp-server", use my_mcp_server
use my_mcp_server::handler::McpHandler;

#[tokio::test]
async fn test_list_tools() {
    let handler = McpHandler::new();
    let context = RequestContext::default();
    
    let result = handler.list_tools(None, context).await.unwrap();
    
    assert!(!result.tools.is_empty());
    assert!(result.tools.iter().any(|t| t.name == "example_tool"));
}

#[tokio::test]
async fn test_call_tool() {
    let handler = McpHandler::new();
    let context = RequestContext::default();
    
    let request = CallToolRequestParam {
        name: "example_tool".to_string(),
        arguments: Some(serde_json::json!({
            "input": "test"
        })),
    };
    
    let result = handler.call_tool(request, context).await;
    assert!(result.is_ok());
}

#[tokio::test]
async fn test_list_prompts() {
    let handler = McpHandler::new();
    let context = RequestContext::default();
    
    let result = handler.list_prompts(None, context).await.unwrap();
    assert!(!result.prompts.is_empty());
}

#[tokio::test]
async fn test_list_resources() {
    let handler = McpHandler::new();
    let context = RequestContext::default();
    
    let result = handler.list_resources(None, context).await.unwrap();
    assert!(!result.resources.is_empty());
}

Implementation Guidelines

1. Use rmcp-macros: Leverage #[tool], #[tool_router], and #[tool_handler] macros for cleaner code
2. Type Safety: Use schemars::JsonSchema for all parameter types
3. Error Handling: Return Result types with proper error messages
4. Async/Await: All handlers must be async
5. State Management: Use Arc<RwLock<T>> for shared state
6. Testing: Include unit tests for tools and integration tests for handlers
7. Logging: Use tracing macros (info!, debug!, warn!, error!)
8. Documentation: Add doc comments to all public items

Example Tool Patterns

Simple Read-Only Tool

#[derive(Debug, Deserialize, JsonSchema)]
pub struct GreetParams {
    pub name: String,
}

#[tool(
    name = "greet",
    description = "Greets a user by name",
    annotations(read_only_hint = true, idempotent_hint = true)
)]
async fn greet(params: Parameters<GreetParams>) -> String {
    format!("Hello, {}!", params.inner().name)
}

Tool with Error Handling

#[derive(Debug, Deserialize, JsonSchema)]
pub struct DivideParams {
    pub a: f64,
    pub b: f64,
}

#[tool(name = "divide", description = "Divides two numbers")]
async fn divide(params: Parameters<DivideParams>) -> Result<f64, String> {
    let p = params.inner();
    if p.b == 0.0 {
        Err("Cannot divide by zero".to_string())
    } else {
        Ok(p.a / p.b)
    }
}

Tool with State

#[tool(
    name = "increment",
    description = "Increments the counter",
    annotations(destructive_hint = true)
)]
async fn increment(state: &ServerState) -> i32 {
    state.increment().await
}

Running the Generated Server

After generation:

cd {project-name}
cargo build
cargo test
cargo run

For Claude Desktop integration:

{
  "mcpServers": {
    "{project-name}": {
      "command": "path/to/{project-name}/target/release/{project-name}",
      "args": []
    }
  }
}

Now generate the complete project based on the user's requirements!