Improve API validation error examples

Author: jelaniwoods

examples/15_proxy.rb

@@ -11,14 +11,37 @@
 puts "\n=== AI::Chat Proxy Examples ==="
 puts
 
-puts "0. Validate API key:"
-chat = AI::Chat.new(api_key_env_var: "PROXY_API_KEY")
-chat.proxy = true
-chat.user("What's the capital of Florida?")
-chat.generate![:content]
-puts "   API Key validated: #{chat.instance_variable_get(:@api_key_validated)}"
+puts "0. Validates API key:"
+chat0 = AI::Chat.new(api_key_env_var: "PROXY_API_KEY")
+chat0.proxy = true
+chat0.user("What's the capital of Florida?")
+chat0.generate![:content]
+puts "   API Key validated: #{chat0.instance_variable_get(:@api_key_validated)}"
+puts
+
+puts "0.a Validates API key when invalid key used and proxy disabled:"
+chat0a = AI::Chat.new(api_key_env_var: "PROXY_API_KEY")
+chat0a.user("What's the capital of Florida?")
+begin
+  chat0a.generate![:content]
+  puts "✗ API validation should have failed"
+rescue AI::Chat::WrongAPITokenUsedError => e
+  puts "✓ API validation correctly rejects call: #{e.message}"
+end
 puts
 
+puts "0.b Validates API key when invalid key used and proxy enabled:"
+chat0b = AI::Chat.new
+chat0b.proxy = true
+chat0b.user("What's the capital of Florida?")
+begin
+  chat0b.generate![:content]
+  puts "✗ API validation should have failed"
+rescue AI::Chat::WrongAPITokenUsedError => e
+  puts "✓ API validation correctly rejects call: #{e.message}"
+end
+puts
+exit 0
 puts "1. Basic conversation:"
 chat = AI::Chat.new(api_key_env_var: "PROXY_API_KEY")
 chat.proxy = true

lib/ai/chat.rb

@@ -572,16 +572,17 @@ def validate_api_key
       # Simple API call to validate the token
       client.models.list
       @api_key_validated = true
-    rescue OpenAI::Errors::AuthenticationError => e
-      if proxy
-        raise WrongAPITokenUsedError, <<~STRING
+    rescue OpenAI::Errors::AuthenticationError
+      message = if proxy
+         <<~STRING
           It looks like you're using an invalid API key. Proxying is enabled, so you must use an OpenAI API key from prepend.me. Please disable proxy or update your API key before generating a response.
         STRING
       else
-        raise WrongAPITokenUsedError, <<~STRING
+        <<~STRING
           It looks like you're using an invalid API key. Check to make sure your API key is valid before generating a response.
         STRING
       end
+      raise WrongAPITokenUsedError, message, cause: nil
     end
 
     # :reek:FeatureEnvy