diff --git a/src/Samples/Program.cs b/src/Samples/Program.cs
index e3ca628..421f002 100644
--- a/src/Samples/Program.cs
+++ b/src/Samples/Program.cs
@@ -6,7 +6,7 @@
 };
 
 // Env supports .env as well as all standard .NET configuration sources
-var grok = new GrokClient(Env.Get("XAI_API_KEY")!, new GrokClientOptions()
+var grok = new GrokClient(Throw.IfNullOrEmpty(Env.Get("XAI_API_KEY")), new GrokClientOptions()
     .UseJsonConsoleLogging(new() { WrapLength = 80 }));
 
 var options = new ChatOptions
diff --git a/src/Weaving/readme.md b/src/Weaving/readme.md
index ed0a0d5..d640ea0 100644
--- a/src/Weaving/readme.md
+++ b/src/Weaving/readme.md
@@ -11,7 +11,7 @@ var messages = new Chat()
     { "user", "What is 101*3?" },
 };
 
-var grok = new GrokClient(Env.Get("XAI_API_KEY")!);
+var grok = new GrokClient(Throw.IfNullOrEmpty(Env.Get("XAI_API_KEY")));
 
 var options = new GrokChatOptions
 {