simplify error msgs im mcp-client

crates/mcp-client/src/client.rs

@@ -10,6 +10,8 @@ use thiserror::Error;
 use tokio::sync::Mutex;
 use tower::{Service, ServiceExt}; // for Service::ready()
 
+pub type BoxError = Box<dyn std::error::Error + Sync + Send>;
+
 /// Error type for MCP client operations.
 #[derive(Debug, Error)]
 pub enum Error {
@@ -31,13 +33,16 @@ pub enum Error {
     #[error("Timeout or service not ready")]
     NotReady,
 
-    #[error("Box error: {0}")]
-    BoxError(Box<dyn std::error::Error + Send + Sync>),
+    #[error("Request timed out")]
+    Timeout(#[from] tower::timeout::error::Elapsed),
+
+    #[error("MCP Server error: {0}")]
+    McpServerError(BoxError),
 }
 
-impl From<Box<dyn std::error::Error + Send + Sync>> for Error {
-    fn from(err: Box<dyn std::error::Error + Send + Sync>) -> Self {
-        Error::BoxError(err)
+impl From<BoxError> for Error {
+    fn from(err: BoxError) -> Self {
+        Error::McpServerError(err)
     }
 }
 

crates/mcp-client/src/service.rs

@@ -50,10 +50,3 @@ where
             .service(McpService::new(transport))
     }
 }
-
-// Implement From<tower::timeout::error::Elapsed> for our Error type
-impl From<tower::timeout::error::Elapsed> for Error {
-    fn from(_: tower::timeout::error::Elapsed) -> Self {
-        Error::Timeout
-    }
-}

crates/mcp-client/src/transport/mod.rs

@@ -4,6 +4,7 @@ use std::collections::HashMap;
 use thiserror::Error;
 use tokio::sync::{mpsc, oneshot, RwLock};
 
+pub type BoxError = Box<dyn std::error::Error + Sync + Send>;
 /// A generic error type for transport operations.
 #[derive(Debug, Error)]
 pub enum Error {
@@ -13,41 +14,23 @@ pub enum Error {
     #[error("Transport was not connected or is already closed")]
     NotConnected,
 
-    #[error("Invalid URL provided")]
-    InvalidUrl,
-
-    #[error("Connection timeout")]
-    Timeout,
-
-    #[error("Failed to send message")]
-    SendFailed,
-
     #[error("Channel closed")]
     ChannelClosed,
 
     #[error("Serialization error: {0}")]
     Serialization(#[from] serde_json::Error),
 
-    #[error("HTTP error: {status} - {message}")]
-    HttpError { status: u16, message: String },
+    #[error("Unsupported message type. JsonRpcMessage can only be Request or Notification.")]
+    UnsupportedMessage,
+
+    #[error("Stdio process error: {0}")]
+    StdioProcessError(String),
 
     #[error("SSE connection error: {0}")]
     SseConnection(String),
 
-    #[error("Connection closed by server")]
-    ConnectionClosed,
-
-    #[error("Unexpected transport error: {0}")]
-    Other(String),
-
-    #[error("Box error: {0}")]
-    BoxError(Box<dyn std::error::Error + Send + Sync>),
-}
-
-impl From<Box<dyn std::error::Error + Send + Sync>> for Error {
-    fn from(err: Box<dyn std::error::Error + Send + Sync>) -> Self {
-        Error::BoxError(err)
-    }
+    #[error("HTTP error: {status} - {message}")]
+    HttpError { status: u16, message: String },
 }
 
 /// A message that can be sent through the transport
@@ -100,7 +83,7 @@ pub async fn send_message(
             sender.send(msg).await.map_err(|_| Error::ChannelClosed)?;
             Ok(JsonRpcMessage::Nil)
         }
-        _ => Err(Error::Other("Unsupported message type".to_string())),
+        _ => Err(Error::UnsupportedMessage),
     }
 }
 

crates/mcp-client/src/transport/stdio.rs

@@ -143,17 +143,17 @@ impl StdioTransport {
             // 0 sets the process group ID equal to the process ID
             .process_group(0) // don't inherit signal handling from parent process
             .spawn()
-            .map_err(|e| Error::Other(e.to_string()))?;
+            .map_err(|e| Error::StdioProcessError(e.to_string()))?;
 
         let stdin = process
             .stdin
             .take()
-            .ok_or_else(|| Error::Other("Failed to get stdin".into()))?;
+            .ok_or_else(|| Error::StdioProcessError("Failed to get stdin".into()))?;
 
         let stdout = process
             .stdout
             .take()
-            .ok_or_else(|| Error::Other("Failed to get stdout".into()))?;
+            .ok_or_else(|| Error::StdioProcessError("Failed to get stdout".into()))?;
 
         Ok((process, stdin, stdout))
     }