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

server/src/handlers/vision.rs

@@ -700,7 +700,7 @@ impl McpTool for ClipboardHandler {
     }
 
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> crate::error::Result<String> {
-        let req: ClipboardTool = serde_json::from_value(args).map_err(|e| e.to_string())?;
+        let req: ClipboardTool = 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)))?;
         match req.action {
             ClipboardAction::Image => {
                 let cached_opt = {