microsoft/autogen · error · ArgumentException

ImageMessage is not supported when message.From is the same

Error message

ImageMessage is not supported when message.From is the same with agent

What it means

Error "ImageMessage is not supported when message.From is the same with agent" thrown in microsoft/autogen.

Source

Thrown at dotnet/src/AutoGen.AzureAIInference/Middleware/AzureAIInferenceChatRequestMessageConnector.cs:225

        }
        else
        {
            return message.From switch
            {
                null when message.Role == Role.User => [new ChatRequestUserMessage(message.Content)],
                null when message.Role == Role.Assistant => [new ChatRequestAssistantMessage() { Content = message.Content }],
                null => throw new InvalidOperationException("Invalid Role"),
                _ => [new ChatRequestUserMessage(message.Content)]
            };
        }
    }

    private IEnumerable<ChatRequestMessage> ProcessImageMessage(IAgent agent, ImageMessage message)
    {
        if (agent.Name == message.From)
        {
            // image message from assistant is not supported
            throw new ArgumentException("ImageMessage is not supported when message.From is the same with agent");
        }

        var imageContentItem = this.CreateChatMessageImageContentItemFromImageMessage(message);
        return [new ChatRequestUserMessage([imageContentItem])];
    }

    private IEnumerable<ChatRequestMessage> ProcessMultiModalMessage(IAgent agent, MultiModalMessage message)
    {
        if (agent.Name == message.From)
        {
            // image message from assistant is not supported
            throw new ArgumentException("MultiModalMessage is not supported when message.From is the same with agent");
        }

        IEnumerable<ChatMessageContentItem> items = message.Content.Select<IMessage, ChatMessageContentItem>(ci => ci switch
        {
            TextMessage text => new ChatMessageTextContentItem(text.Content),
            ImageMessage image => this.CreateChatMessageImageContentItemFromImageMessage(image),

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Images from the assistant are not supported; only user messages may carry images

Example fix

Do not attach ImageMessage with From equal to the agent name

When it happens

Trigger: Thrown at dotnet/src/AutoGen.AzureAIInference/Middleware/AzureAIInferenceChatRequestMessageConnector.cs:225 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/3c73e7331fa5b51e. Report an issue: GitHub.