Fix error swallowing by propagating JSON serialization errors to LLM

server/src/handlers/notes.rs

@@ -49,8 +49,8 @@ impl McpTool for ReadStickyNotesHandler {
     async fn execute(&self, _args: Value, state: Arc<MemoryState>) -> Result<String, String> {
         let data = state
             .sticky
-            .read_with(|s| serde_json::to_string(s).unwrap_or_else(|_| "[]".to_string()));
-        Ok(data.to_string())
+            .read_with(|s| serde_json::to_string(s).map_err(|e| e.to_string()))?;
+        Ok(data)
     }
 }
 
@@ -167,9 +167,9 @@ impl McpTool for ReadHandoffMemosHandler {
                     }
                 })
                 .collect();
-            serde_json::to_string(&filtered).unwrap_or_default()
-        });
-        Ok(data.to_string())
+            serde_json::to_string(&filtered).map_err(|e| e.to_string())
+        })?;
+        Ok(data)
     }
 }