This is a comment left during a code review.
Path: nemo_retriever/src/nemo_retriever/graph/react_agent_operator.py
Line: 437-441

Comment:
**Single-query fast path skips the exception safety net present in the multi-query path**

When `len(query_rows) == 1`, `_run_single_query` is called directly with no surrounding `try/except`. The multi-query path (lines 446-463) wraps `future.result()` with handlers for `TimeoutError`, `RuntimeError`, `requests.RequestException`, `json.JSONDecodeError`, and a broad `except Exception` fallback, ensuring one failing query never kills the batch. In the single-query branch any unhandled exception from `_run_single_query` propagates straight through `process()`. While the inner loop already catches most expected errors, aligning both paths prevents silent behavioral divergence for unexpected exceptions.

```suggestion
        if len(query_rows) == 1:
            # Fast path: single query, no threading overhead
            qid, qtxt = query_rows[0]
            try:
                rows.extend(self._run_single_query(qid, qtxt, api_key))
            except Exception as exc:
                logger.warning("ReActAgentOperator: query %r failed: %s", qid, exc, exc_info=True)
```

How can I resolve this? If you propose a fix, please make it concise.

---

This is a comment left during a code review.
Path: nemo_retriever/src/nemo_retriever/graph/react_agent_operator.py
Line: 657-693

Comment:
**Unused credential parameter in `_call_retriever`**

The third parameter (`Optional[str]`) is accepted but never used inside the method — `self._retriever_fn` is called with only `query_text` and `fetch_k`. Every call site in `_run_single_query` passes the resolved credential, which is silently dropped. Either remove the parameter (the retriever is expected to close over its own auth) or document why it is forwarded but unused, to avoid misleading future readers.

How can I resolve this? If you propose a fix, please make it concise.

---

This is a comment left during a code review.
Path: nemo_retriever/tests/test_agentic_operators.py
Line: 293

Comment:
**`MagicMock` without `spec=` will hide future `retriever_fn` contract drift**

Per the mocking-discipline rule, `MagicMock(return_value=...)` without `spec=` or `spec_set=` accepts any attribute access or call signature on the mock, so a change to the expected `retriever_fn(query_text, top_k)` signature would go undetected. Use `spec=` with the concrete callable type or a `Callable` annotation to catch API drift early.

How can I resolve this? If you propose a fix, please make it concise.