microsoft/autogen · error · Exception

Please set OPENAI_API_KEY environment variable.

Error message

Please set OPENAI_API_KEY environment variable.

What it means

Same file as error 83: after the BING_API_KEY guard passes, the sample throws this if OPENAI_API_KEY is also missing, because it builds the chat-completion kernel with AddOpenAIChatCompletion('gpt-3.5-turbo', openAIKey). The sample needs two independent keys: a Bing key for search and an OpenAI key for the LLM.

Source

Thrown at dotnet/samples/AgentChat/AutoGen.SemanticKernel.Sample/Use_Bing_Search_With_Semantic_Kernel_Agent.cs:20

// Use_Bing_Search_With_Semantic_Kernel_Agent.cs

using AutoGen.Core;
using AutoGen.SemanticKernel.Extension;
using Microsoft.SemanticKernel;
using Microsoft.SemanticKernel.Plugins.Web;
using Microsoft.SemanticKernel.Plugins.Web.Bing;

namespace AutoGen.SemanticKernel.Sample;

public class Use_Bing_Search_With_Semantic_Kernel_Agent
{
    public static async Task RunAsync()
    {
        var bingApiKey = Environment.GetEnvironmentVariable("BING_API_KEY") ?? throw new Exception("BING_API_KEY environment variable is not set");
        var bingSearch = new BingConnector(bingApiKey);
        var webSearchPlugin = new WebSearchEnginePlugin(bingSearch);

        var openAIKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY") ?? throw new Exception("Please set OPENAI_API_KEY environment variable.");
        var modelId = "gpt-3.5-turbo";
        var kernelBuilder = Kernel.CreateBuilder()
            .AddOpenAIChatCompletion(modelId: modelId, apiKey: openAIKey);
        kernelBuilder.Plugins.AddFromObject(webSearchPlugin);

        var kernel = kernelBuilder.Build();

        var skAgent = new SemanticKernelAgent(
            kernel: kernel,
            name: "assistant",
            systemMessage: "You are a helpful AI assistant")
            .RegisterMessageConnector() // register message connector so it support AutoGen built-in message types like TextMessage.
            .RegisterPrintMessage(); // pretty print the message to the console

        await skAgent.SendAsync("Tell me more about gpt-4-o");
    }
}

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Export OPENAI_API_KEY alongside BING_API_KEY in the same session and rerun.
2. If your org uses Azure OpenAI, edit the sample to use AddAzureOpenAIChatCompletion with endpoint/deployment/key configuration instead.
3. Add both keys to launchSettings.json when debugging from an IDE so they are always present.

Example fix

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

// after
var openAIKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY")
    ?? throw new InvalidOperationException("OPENAI_API_KEY is not set; this sample needs both BING_API_KEY and OPENAI_API_KEY.");

var missing = new[] { "BING_API_KEY", "OPENAI_API_KEY" }
    .Where(k => string.IsNullOrWhiteSpace(Environment.GetEnvironmentVariable(k)))
    .ToArray();
if (missing.Length > 0) { Console.Error.WriteLine($"Missing env vars: {string.Join(", ", missing)}"); return; }

When it happens

Trigger: Running the Bing-search sample with BING_API_KEY set but OPENAI_API_KEY unset; the exception fires at the openAIKey line just after the Bing connector is created.

Common situations: Developer configured only the search key; OpenAI key present in another shell/session; organization uses Azure OpenAI only, so no public-OpenAI key exists.

Related errors

• Please set OPENAI_API_KEY environment variable.
• Please set OPENAI_API_KEY environment variable.
• BING_API_KEY environment variable is not set
• 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/fc9d6be6ad505b7e. Report an issue: GitHub.