Struct McpHub 

pub struct McpHub { /* private fields */ }

Central hub for MCP tool routing across multiple servers.

The McpHub provides:

• Connection management for multiple MCP servers
• Tool discovery and caching
• Automatic routing of tool calls to the correct server
• Circuit breaker protection for resilience
• Parallel tool discovery for performance

Example

use mcp::{McpHub, McpServerConnectionConfig};

let hub = McpHub::new();

// Connect to an external server
let config = McpServerConnectionConfig::stdio("my-server", "node", vec!["server.js".into()]);
hub.connect(config).await?;

// List all available tools
let tools = hub.list_all_tools().await?;

// Call a tool (automatically routed to correct server)
let result = hub.call_tool("my_tool", serde_json::json!({"arg": "value"})).await?;

Implementations

impl McpHub

pub fn new() -> Self

Create a new empty hub.

pub fn with_discovery_timeout(timeout: Duration) -> Self

Create a hub with a custom discovery timeout.

pub async fn connect( &self, config: McpServerConnectionConfig, ) -> Result<Arc<dyn McpTransport>, McpTransportError>

Connect to an MCP server.

This method:

1. Creates the appropriate transport based on config
2. Initializes the connection
3. Discovers tools and caches the mapping
4. Returns the transport for direct access if needed

pub async fn call_tool( &self, name: &str, args: Value, ) -> Result<Value, McpTransportError>

Call a tool, automatically routing to the correct server.

Uses circuit breaker to prevent cascading failures - if a server is unhealthy, requests will be rejected immediately.

pub async fn list_tools( &self, ) -> Result<Vec<(String, McpToolDefinition)>, McpTransportError>

List all tools from all connected servers.

pub async fn list_all_tools( &self, ) -> Result<Vec<McpToolDefinition>, McpTransportError>

Get all registered tools as a flat list.

pub async fn discover_tools_parallel( &self, ) -> Result<Vec<(String, McpToolDefinition)>, McpTransportError>

Discover tools from all servers in parallel.

This is faster than sequential discovery when connecting to many servers.

pub async fn refresh_tool_cache(&self) -> Result<(), McpTransportError>

Populate the tool cache by querying all servers (parallel).

pub async fn shutdown_all(&self) -> Result<(), McpTransportError>

Shutdown all connected servers.

pub async fn disconnect( &self, server_name: &str, ) -> Result<(), McpTransportError>

Disconnect a specific server.

pub fn list_servers(&self) -> Vec<String>

Get list of connected server names.

pub fn is_connected(&self, server_name: &str) -> bool

Check if a server is connected.

pub async fn health_check(&self) -> Vec<(String, bool)>

Get health status of all servers (includes circuit breaker state).

pub fn server_for_tool(&self, tool_name: &str) -> Option<String>

Get the server name that provides a specific tool.

pub fn circuit_breaker_stats( &self, server_name: &str, ) -> Option<CircuitBreakerStats>

Get circuit breaker statistics for a server.

pub fn reset_circuit_breaker(&self, server_name: &str)

Reset circuit breaker for a server (e.g., after manual recovery).

Trait Implementations

impl Default for McpHub

fn default() -> Self

Returns the “default value” for a type.