fix: restore AppError::Internal for AST parser error, keeping BadRequest for JSON schema validation

server/src/handlers/env.rs

@@ -21,7 +21,7 @@ impl McpTool for EnvironmentHandler {
     }
 
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> crate::error::Result<String> {
-        let req: EnvironmentTool = serde_json::from_value(args).map_err(|e| e.to_string())?;
+        let req: EnvironmentTool = serde_json::from_value(args).map_err(|e| crate::error::AppError::BadRequest(format!("Schema validation failed. Your JSON arguments do not match the expected tool schema: {}", e)))?;
         let ns = req
             .namespace
             .unwrap_or_else(crate::models::default_namespace);