NousResearch/hermes-agent · error · RuntimeError

Responses API returned no output items

Error message

Responses API returned no output items

What it means

Error "Responses API returned no output items" thrown in NousResearch/hermes-agent.

Source

Thrown at agent/codex_responses_adapter.py:1315

                "Codex response has empty output but output_text is present (%d chars); "
                "synthesizing output item.", len(out_text.strip()),
            )
            output = [SimpleNamespace(
                type="message", role="assistant", status="completed",
                content=[SimpleNamespace(type="output_text", text=out_text.strip())],
            )]
            response.output = output
        elif response_incomplete_content_filter:
            # This is a deterministic provider safety block, not a partial
            # answer. Synthesize an empty message so finish_reason below becomes
            # content_filter and the conversation loop can fallback/surface it
            # instead of burning three continuation attempts.
            output = [SimpleNamespace(
                type="message", role="assistant", status="completed", content=[]
            )]
            response.output = output
        else:
            raise RuntimeError("Responses API returned no output items")

    if response_status in {"failed", "cancelled"}:
        error_obj = getattr(response, "error", None)
        error_msg = _format_responses_error(error_obj, response_status)
        raise RuntimeError(error_msg)

    content_parts: List[str] = []
    reasoning_parts: List[str] = []
    reasoning_items_raw: List[Dict[str, Any]] = []
    message_items_raw: List[Dict[str, Any]] = []
    tool_calls: List[Any] = []
    has_incomplete_items = response_status in {"queued", "in_progress", "incomplete"}
    saw_streaming_or_item_incomplete = response_status in {"queued", "in_progress"}
    saw_commentary_phase = False
    saw_final_answer_phase = False
    saw_reasoning_item = False

    # Server-side built-in tool calls (xAI's native web_search, code

View on GitHub (pinned to c896c09c42)

Solutions

1. Retry the request; the Responses API returned no output items.
2. Check the request (model, tools, input) is valid for the Responses endpoint.
3. Review provider logs for an upstream error that yielded an empty output.

When it happens

Trigger: Thrown at agent/codex_responses_adapter.py:1315 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of NousResearch/hermes-agent@c896c09c42 (2026-08-14). Data as JSON: /api/errors/3fb5889c4cfd78a1. Report an issue: GitHub.