microsoft/semantic-kernel · error · ArgumentException

The streaming configuration must be null for non-streaming r

Error message

The streaming configuration must be null for non-streaming responses.

What it means

Thrown by the internal non-streaming InvokeInternalAsync on BedrockAgent when the request's StreamingConfigurations has StreamFinalResponse set true. Because this is the non-streaming code path, a streaming configuration is contradictory; the guard prevents misuse where a caller (or a shared request builder) accidentally enables streaming on a non-streaming call.

Source

Thrown at dotnet/src/Agents/Bedrock/BedrockAgent.cs:434

    }

    #region internal methods

    internal string CodeInterpreterActionGroupSignature { get => $"{this.GetDisplayName()}_CodeInterpreter"; }
    internal string KernelFunctionActionGroupSignature { get => $"{this.GetDisplayName()}_KernelFunctions"; }
    internal string UseInputActionGroupSignature { get => $"{this.GetDisplayName()}_UserInput"; }

    #endregion

    #region private methods

    private IAsyncEnumerable<ChatMessageContent> InvokeInternalAsync(
        InvokeAgentRequest invokeAgentRequest,
        KernelArguments? arguments,
        CancellationToken cancellationToken = default)
    {
        return invokeAgentRequest.StreamingConfigurations != null && (invokeAgentRequest.StreamingConfigurations.StreamFinalResponse ?? false)
            ? throw new ArgumentException("The streaming configuration must be null for non-streaming responses.")
            : InvokeInternal();

        // Collect all responses from the agent and return them as a single chat message content since this
        // is a non-streaming API.
        // The Bedrock Agent API streams beck different types of responses, i.e. text, files, metadata, etc.
        // The Bedrock Agent API also won't stream back any content when it needs to call a function. It will
        // only start streaming back content after the function has been called and the response is ready.
        async IAsyncEnumerable<ChatMessageContent> InvokeInternal()
        {
            ChatMessageContentItemCollection items = [];
            string content = "";
            Dictionary<string, object?> metadata = [];
            List<object?> innerContents = [];

            await foreach (var message in this.InternalInvokeAsync(invokeAgentRequest, arguments, cancellationToken).ConfigureAwait(false))
            {
                items.AddRange(message.Items);
                content += message.Content ?? "";

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Do not set StreamingConfigurations (or set it null) when invoking the non-streaming path.
2. If reusing a request builder, parameterize whether streaming is enabled and only set StreamingConfigurations on the streaming path.

Example fix

// before
var request = new InvokeAgentRequest
{
    StreamingConfigurations = new() { StreamFinalResponse = true },
};
await agent.InvokeInternalAsync(request, args); // non-streaming -> throws 175

// after
var request = new InvokeAgentRequest();
// StreamingConfigurations left null for non-streaming
await agent.InvokeInternalAsync(request, args);

if (request.StreamingConfigurations is not null && (request.StreamingConfigurations.StreamFinalResponse ?? false))
    request.StreamingConfigurations = null; // clear for non-streaming path

static bool IsNonStreamingSafe(InvokeAgentRequest r) =>
    r.StreamingConfigurations is null || !(r.StreamingConfigurations.StreamFinalResponse ?? false);

try { await agent.InvokeInternalAsync(request, args, ct); }
catch (ArgumentException ex) when (ex.Message.Contains("null for non-streaming"))
{ /* clear StreamingConfigurations and retry */ }

When it happens

Trigger: Calling the non-streaming invoke path with an InvokeAgentRequest whose StreamingConfigurations.StreamFinalResponse is true. Often happens when the same request object is reused for both paths, or a wrapper sets streaming config unconditionally.

Common situations: Request-builder helper that always sets StreamFinalResponse; copy-pasted request object from a streaming call into a non-streaming call.

Related errors

• The streaming configuration must have StreamFinalResponse se
• The Bedrock agent requires a message to be invoked.
• Bedrock agents must be invoked with a user message
• Invalid role: {authorRole}
• Message content cannot be null.

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/a73bd5012df17401. Report an issue: GitHub.