fix: address review feedback on MCP parameter handling and run status

crates/tower-cmd/src/mcp.rs

@@ -854,8 +854,15 @@ impl TowerService {
         Self::modify_towerfile(&request.common, |tf| {
             let existing = tf.parameters.iter().find(|p| p.name == name)
                 .ok_or_else(|| format!("Parameter '{name}' not found"))?;
+            let target_name = request
+                .new_name
+                .clone()
+                .unwrap_or_else(|| existing.name.clone());
+            if target_name != name && tf.parameters.iter().any(|p| p.name == target_name) {
+                return Err(format!("Parameter '{}' already exists", target_name));
+            }
             let param = Parameter {
-                name: request.new_name.unwrap_or_else(|| existing.name.clone()),
+                name: target_name,
                 description: request.description.unwrap_or_else(|| existing.description.clone()),
                 default: request.default.unwrap_or_else(|| existing.default.clone()),
                 hidden: request.hidden.unwrap_or(existing.hidden),

crates/tower-cmd/src/run.rs

@@ -254,6 +254,16 @@ where
             output::error(&format!("Your local run crashed with exit code: {}", code));
             return Err(Error::AppCrashed);
         }
+        Status::Failed {
+            error_code,
+            error_message,
+        } => {
+            output::error(&format!(
+                "Your local run failed due to a platform error (code: {}, message: {})",
+                error_code, error_message
+            ));
+            return Err(Error::AppCrashed);
+        }
         _ => {
             debug!("Unexpected status after monitoring: {:?}", status_result);
             output::error("An unexpected error occurred while monitoring your local run status!");
@@ -703,6 +713,10 @@ async fn monitor_cli_status(
                         debug!("Run crashed, stopping status monitoring");
                         return status;
                     }
+                    Status::Failed { .. } => {
+                        debug!("Run failed at platform layer, stopping status monitoring");
+                        return status;
+                    }
                     _ => {
                         debug!("Handle status: other, continuing to monitor");
                         sleep(Duration::from_millis(100)).await;