microsoft/autogen · error · ValueError

No TaskResult or Response was processed.

Error message

No TaskResult or Response was processed.

What it means

The console UI helper raises ValueError when a stream completes without any TaskResult or Response object being processed — the loop iterated only over events/other message types (or nothing at all). This indicates the run ended abnormally early or the stream source produced no terminal result.

Source

Thrown at python/packages/autogen-agentchat/src/autogen_agentchat/ui/_console.py:202

                    streaming_chunks.clear()
                    # Chunked messages are already printed, so we just print a newline.
                    await aprint("", end="\n", flush=True)
                elif isinstance(message, MultiModalMessage):
                    await aprint(message.to_text(iterm=render_image_iterm), end="\n", flush=True)
                else:
                    await aprint(message.to_text(), end="\n", flush=True)
                if message.models_usage:
                    if output_stats:
                        await aprint(
                            f"[Prompt tokens: {message.models_usage.prompt_tokens}, Completion tokens: {message.models_usage.completion_tokens}]",
                            end="\n",
                            flush=True,
                        )
                    total_usage.completion_tokens += message.models_usage.completion_tokens
                    total_usage.prompt_tokens += message.models_usage.prompt_tokens

    if last_processed is None:
        raise ValueError("No TaskResult or Response was processed.")

    return last_processed

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Ensure the underlying run_stream always yields a final TaskResult (use the built-in team/agent run_stream implementations).
2. If the run was cancelled or errored, handle that path separately instead of relying on console() to return a value.
3. For custom task runners, yield TaskResult(messages=[...]) as the last item of the stream.

Example fix

# before
async for _ in team.run_stream(task="x"):  # if cancelled, no TaskResult
    ...
result = await console(run_stream)  # ValueError

# after
stream = team.run_stream(task="x")
result = await console(stream)  # rely on built-in teams which always emit TaskResult; catch cancellation upstream

try:
    result = await console(stream, output_stats=True)
except ValueError as e:
    if "No TaskResult" in str(e):
        # stream ended without a TaskResult: cancelled or errored run
        raise RuntimeError("Run produced no TaskResult; inspect cancellation/errors upstream") from e
    raise

When it happens

Trigger: Calling the console(...) helper over a run_stream that yields only BaseAgentEvent items or nothing before finishing; a team whose stream was cancelled or errored such that the final TaskResult never arrived.

Common situations: Consuming console output of a team run that raised internally, was cancelled via CancellationToken, or a custom task runner that yields messages but never a TaskResult.

Related errors

• Please set OPENAI_API_KEY environment variable.
• Failed to deserialize response
• Value was null.
• Role mismatch
• From mismatch

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/3641caff192e15fb. Report an issue: GitHub.