microsoft/autogen · error · Exception

Please set AZURE_OPENAI_ENDPOINT environment variable.

Error message

Please set AZURE_OPENAI_ENDPOINT environment variable.

What it means

Second guard in LLMConfiguration.GetAzureOpenAIGPT3_5_Turbo(): after the API key, it requires AZURE_OPENAI_ENDPOINT because AzureOpenAIConfig needs the resource endpoint URL (e.g. https://<resource>.openai.azure.com) to route requests. Seeing this exact message means AZURE_OPENAI_API_KEY was present but the endpoint variable was not.

Source

Thrown at dotnet/samples/AgentChat/AutoGen.Basic.Sample/LLMConfiguration.cs:22

using OpenAI;
using OpenAI.Chat;

namespace AutoGen.Basic.Sample;

internal static class LLMConfiguration
{
    public static ChatClient GetOpenAIGPT4o_mini()
    {
        var openAIKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY") ?? throw new Exception("Please set OPENAI_API_KEY environment variable.");
        var modelId = "gpt-4o-mini";

        return new OpenAIClient(openAIKey).GetChatClient(modelId);
    }

    public static AzureOpenAIConfig GetAzureOpenAIGPT3_5_Turbo(string? deployName = null)
    {
        var azureOpenAIKey = Environment.GetEnvironmentVariable("AZURE_OPENAI_API_KEY") ?? throw new Exception("Please set AZURE_OPENAI_API_KEY environment variable.");
        var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new Exception("Please set AZURE_OPENAI_ENDPOINT environment variable.");
        deployName = deployName ?? Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOY_NAME") ?? throw new Exception("Please set AZURE_OPENAI_DEPLOY_NAME environment variable.");
        return new AzureOpenAIConfig(endpoint, deployName, azureOpenAIKey);
    }
}

View on GitHub (pinned to 027ecf0a37)

Solutions

Set AZURE_OPENAI_ENDPOINT to your resource endpoint (Azure Portal -> your Azure OpenAI resource -> Keys and Endpoint -> Endpoint), e.g. export AZURE_OPENAI_ENDPOINT=https://myresource.openai.azure.com.
Also set AZURE_OPENAI_DEPLOY_NAME, which the helper validates immediately after this line.
Copy all three values (key, endpoint, deployment) from the same Portal page to avoid partial config.
Use the exact variable names the helper reads — no OPENAI_ENDPOINT or AZURE_OPENAI_RESOURCE variants.

Example fix

// before
var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new Exception("Please set AZURE_OPENAI_ENDPOINT environment variable.");

// after
var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT")
    ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set. Use the Endpoint value from your Azure OpenAI resource's 'Keys and Endpoint' page.");

Defensive patterns

Strategy: validation

Validate before calling

var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT");
if (string.IsNullOrWhiteSpace(endpoint) || !Uri.IsWellFormedUriString(endpoint, UriKind.Absolute))
{
    throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT must be set to your resource endpoint, e.g. https://<resource>.openai.azure.com");
}

Try / catch

try
{
    var config = LLMConfiguration.GetAzureOpenAIGPT3_5_Turbo();
}
catch (Exception ex) when (ex.Message.Contains("AZURE_OPENAI_ENDPOINT"))
{
    Console.Error.WriteLine($"Incomplete Azure OpenAI config: {ex.Message}");
}

Prevention

Set the endpoint at the same time as the key — both come from the same Portal page.
Use the full https://<resource>.openai.azure.com URL; a bare resource name passes the null check but breaks later.
Batch-validate all AZURE_OPENAI_* variables in one startup check.

When it happens

Trigger: A sample calling LLMConfiguration.GetAzureOpenAIGPT3_5_Turbo() where AZURE_OPENAI_API_KEY is set but AZURE_OPENAI_ENDPOINT is unset/empty. The deployment-name check (AZURE_OPENAI_DEPLOY_NAME) runs after and has not executed yet.

Common situations: Partial Azure configuration — developers copy the key but forget the endpoint from the same Azure Portal page; endpoint stored under a different name (OPENAI_ENDPOINT); CI secret list missing one of the three Azure variables.

Related errors

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/7aa52f7d8af864ea. Report an issue: GitHub.