microsoft/aspire · error · InvalidOperationException

An interaction ID is required when uploading a file.

Error message

An interaction ID is required when uploading a file.

What it means

UploadFileAsync requires the upload to be associated with an active interaction; it throws InvalidOperationException when request.InteractionId is zero or negative. The uploaded file must be attached to a pending file-upload interaction identified by that id.

Solutions

1. Set InteractionId to the id of the pending file-upload interaction that requested the file.
2. Only call UploadFileAsync from within the interaction callback where the interaction id is available.
3. Verify the id was copied correctly from the interaction payload (not left at the default 0).

Example fix

// before
await rpc.UploadFileAsync(new UploadFileRequest { FileName = f, Data = bytes }); // InteractionId = 0
// after
await rpc.UploadFileAsync(new UploadFileRequest { FileName = f, Data = bytes, InteractionId = interaction.Id, InputName = "file" });

if (request.InteractionId <= 0)
{
    throw new InvalidOperationException("Set InteractionId from the pending file-upload interaction before uploading.");
}

static bool HasInteractionId(UploadFileRequest r) => r.InteractionId > 0;

try
{
    await rpc.UploadFileAsync(request, cancellationToken);
}
catch (InvalidOperationException ex) when (ex.Message.Contains("interaction ID is required"))
{
    // rebuild the request with the active interaction's id
}

When it happens

Trigger: Calling UploadFileAsync with a request whose InteractionId was never set (default 0) or is a stale/negative value — e.g., constructing UploadFileRequest without an interaction context.

Common situations: Uploading a file outside of an actual file-upload interaction flow; reusing a request object whose interaction id field defaulted to 0; an interaction that already completed so the stored id is no longer valid/positive in caller state.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• An input name is required when uploading a file.
• -32000
• Already connected to AppHost backchannel.
• AppHost server process exited before the RPC connection…
• callback ID missing

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/d4e2f1473048282e. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting/Backchannel/AppHostRpcTarget.cs:263

        await activityReporter.CompleteInteractionAsync(promptId, answers, updateResponse: true, cancellationToken).ConfigureAwait(false);
    }

    /// <summary>
    /// Registers a local file in the upload store by copying it to a managed temp location.
    /// Returns the file ID that can be used to reference the file in interaction responses.
    /// </summary>
    public async Task<UploadFileResponse> UploadFileAsync(UploadFileRequest request, CancellationToken cancellationToken = default)
    {
        var maxUploadSize = FileUploadHelpers.GetMaxFileUploadSize(configuration);

        if (request.Data.Length > maxUploadSize)
        {
            throw new InvalidOperationException($"File '{request.FileName}' exceeds the maximum upload size of {maxUploadSize} bytes.");
        }

        if (request.InteractionId <= 0)
        {
            throw new InvalidOperationException("An interaction ID is required when uploading a file.");
        }
        if (string.IsNullOrEmpty(request.InputName))
        {
            throw new InvalidOperationException("An input name is required when uploading a file.");
        }

        var (fileId, filePath) = fileUploadStore.CreateEntry(request.FileName, request.InteractionId, request.InputName);

        try
        {
            var destStream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None, bufferSize: 81920, useAsync: true);
            await using (destStream.ConfigureAwait(false))
            {
                await destStream.WriteAsync(request.Data, cancellationToken).ConfigureAwait(false);
            }
        }
        catch
        {

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