GPT-5.2 (Azure AI Foundry, Canada East) Chat Completions ignores PDF files (inline CreateFilePart + uploaded file_id both ignored) — Azure.AI.OpenAI 2.2.0-beta.4

Hi everyone,

I’m seeing what looks like a model/deployment behavior change when moving from a GPT-4.1 deployment to GPT-5.2 in Azure AI Foundry. My models are deployed in Canada East.

What I’m trying to do

Include a PDF as part of a Chat Completions request, so the model can summarize/quote from it.

What worked before (GPT-4.1)

With GPT-4.1, I could include a PDF using ChatMessageContentPart.CreateFilePart(...) and the model clearly used the PDF content in its response.

What happens now (GPT-5.2)

With GPT-5.2, the call returns success (no refusal, no error), but the PDF content is ignored. The answer is generic and behaves as if the file was not provided.

I tried these two approaches:

1. Inline file part (bytes in request)
2. Upload first + reference by file id (The upload was successful, but again, file content was ignored)

Packages / versions

<PackageReference Include="Azure.AI.OpenAI" Version="2.2.0-beta.4" />
<PackageReference Include="Azure.Core" Version="1.54.0" />
<PackageReference Include="OpenAI" Version="2.2.0-beta.4" />
<PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="2.3.9" />

Region / deployment

• Azure AI Foundry
• Region: Canada East
• Model deployment: gpt-5.2
• Previously: gpt-4.1

Minimal code (upload + fileId reference)

using Azure.AI.OpenAI;
using OpenAI.Chat;
using OpenAI.Files;
using System.ClientModel;
var azureClient = new AzureOpenAIClient(new Uri(endpoint), new ApiKeyCredential(apiKey));
var chatClient = azureClient.GetChatClient(deploymentName);   // gpt-5.2 deployment
var fileClient = azureClient.GetOpenAIFileClient();
var upload = fileClient.UploadFile(localPdfPath, FileUploadPurpose.Assistants);
var fileId = upload.Value.Id;
#pragma warning disable OPENAI001
var parts = new List<ChatMessageContentPart>
{
    ChatMessageContentPart.CreateTextPart("Summarize the attached PDF and quote the first paragraph verbatim."),
    ChatMessageContentPart.CreateFilePart(fileId),
};
#pragma warning restore OPENAI001
var messages = new List<ChatMessage>
{
    ChatMessage.CreateUserMessage(parts)
};
var completion = chatClient.CompleteChat(messages);
Console.WriteLine(completion.Value.Content[0].Text);

Minimal code (inline bytes in request)

#pragma warning disable OPENAI001
var parts = new List<ChatMessageContentPart>
{
    ChatMessageContentPart.CreateTextPart("Summarize the attached PDF."),
    ChatMessageContentPart.CreateFilePart(
        BinaryData.FromBytes(pdfBytes, "application/pdf"),
        "application/pdf",
        "document.pdf")
};
#pragma warning restore OPENAI001

Questions

1. Does GPT-5.2 on Azure currently support using PDFs in Chat Completions via ChatMessageContentPart.CreateFilePart(...) (either inline bytes or fileId)?
2. If not, what’s the recommended Azure-supported approach for document grounding with GPT-5.2 (Responses API? Assistants + vector store? something else)?
3. Is this a known limitation/bug for gpt-5.2 or for Canada East deployments?
4. Are there any required request options, headers, or deployment settings to enable file usage?

Any guidance or confirmation would be appreciated. I can provide sanitized logs / raw request payload if needed.