microsoft/autogen · error · InvalidOperationException

Please set environment variable OPENAI_API_KEY

Error message

Please set environment variable OPENAI_API_KEY

What it means

Guard in the o1-preview connection sample: it reads OPENAI_API_KEY and throws InvalidOperationException when absent, because OpenAIClient(apiKey) must authenticate the o1-preview chat client. Sample-authored fail-fast: thrown before the OpenAIChatAgent (configured with null systemMessage/temperature/maxTokens for o1-preview limitations) is created.

Source

Thrown at dotnet/samples/AgentChat/AutoGen.OpenAI.Sample/Connect_To_OpenAI_o1_preview.cs:14

// Copyright (c) Microsoft Corporation. All rights reserved.
// Connect_To_OpenAI_o1_preview.cs

using AutoGen.Core;
using OpenAI;

namespace AutoGen.OpenAI.Sample;

public class Connect_To_OpenAI_o1_preview
{
    public static async Task RunAsync()
    {
        #region create_agent
        var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY") ?? throw new InvalidOperationException("Please set environment variable OPENAI_API_KEY");
        var openAIClient = new OpenAIClient(apiKey);

        // until 2024/09/12
        // openai o1-preview doesn't support systemMessage, temperature, maxTokens, streaming output
        // so in order to use OpenAIChatAgent with o1-preview, you need to set those parameters to null
        var agent = new OpenAIChatAgent(
            chatClient: openAIClient.GetChatClient("o1-preview"),
            name: "assistant",
            systemMessage: null,
            temperature: null,
            maxTokens: null,
            seed: 0)
            // by using RegisterMiddleware instead of RegisterStreamingMiddleware
            // it turns an IStreamingAgent into an IAgent and disables streaming
            .RegisterMiddleware(new OpenAIChatRequestMessageConnector())
            .RegisterPrintMessage();
        #endregion create_agent

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Export OPENAI_API_KEY in the shell or IDE run profile that launches the sample.
2. Confirm your organization has been granted access to the o1-preview model, otherwise the next failure is an API-level model-access error.
3. Respect the sample's o1-preview constraints (no systemMessage, temperature, maxTokens, streaming) when adapting the code.
4. If o1-preview is unavailable to your account, swap the model name to one you can access.

Example fix

// before
var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY") ?? throw new InvalidOperationException("Please set environment variable OPENAI_API_KEY");

// after
var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY")
    ?? throw new InvalidOperationException("OPENAI_API_KEY is not set; export it before running this o1-preview sample.");

var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY");
if (string.IsNullOrWhiteSpace(apiKey))
{
    Console.Error.WriteLine("Set OPENAI_API_KEY before running the o1-preview sample.");
    return;
}

try
{
    await Connect_To_OpenAI_o1_preview.RunAsync();
}
catch (InvalidOperationException ex) when (ex.Message.Contains("OPENAI_API_KEY"))
{
    Console.Error.WriteLine($"Missing credential: {ex.Message}");
}

When it happens

Trigger: Calling Connect_To_OpenAI_o1_preview.RunAsync() with OPENAI_API_KEY unset or empty in the process. Nothing network-related runs before the throw.

Common situations: Running the OpenAI sample project without credentials; key expired or not granted o1-preview access (that fails later at the API, not here); IDE processes missing shell exports.

Related errors

• Please set OPENAI_API_KEY environment variable.
• Please set OPENAI_API_KEY environment variable.
• Please set OPENAI_API_KEY environment variable.
• Please set OPENAI_API_KEY environment variable.
• Please set OPENAI_API_KEY environment variable.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/2ae979cb785343a7. Report an issue: GitHub.