fix(tracing): add system prompt, model to google genai (#18424)

Related to getsentry/testing-ai-sdk-integrations#10

Fix JS-1218

Author: isaacs

packages/core/src/tracing/google-genai/index.ts

@@ -16,6 +16,7 @@ import {
   GEN_AI_REQUEST_TEMPERATURE_ATTRIBUTE,
   GEN_AI_REQUEST_TOP_K_ATTRIBUTE,
   GEN_AI_REQUEST_TOP_P_ATTRIBUTE,
+  GEN_AI_RESPONSE_MODEL_ATTRIBUTE,
   GEN_AI_RESPONSE_TEXT_ATTRIBUTE,
   GEN_AI_RESPONSE_TOOL_CALLS_ATTRIBUTE,
   GEN_AI_SYSTEM_ATTRIBUTE,
@@ -134,27 +135,48 @@ function extractRequestAttributes(
  * Handles different parameter formats for different Google GenAI methods.
  */
 function addPrivateRequestAttributes(span: Span, params: Record<string, unknown>): void {
+  const messages: { role: 'system' | 'user'; content: string | string[] }[] = [];
+
+  // include system prompt if present in config param
+  if (
+    'config' in params &&
+    params.config &&
+    typeof params.config === 'object' &&
+    'systemInstruction' in params.config
+  ) {
+    const content = params.config.systemInstruction as string | string[];
+    messages.push({ role: 'system', content });
+  }
+
   // For models.generateContent: ContentListUnion: Content | Content[] | PartUnion | PartUnion[]
   if ('contents' in params) {
-    const contents = params.contents;
     // For models.generateContent: ContentListUnion: Content | Content[] | PartUnion | PartUnion[]
-    const truncatedContents = getTruncatedJsonString(contents);
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: truncatedContents });
+    messages.push({
+      role: 'user',
+      content: getTruncatedJsonString(params.contents),
+    });
   }
 
   // For chat.sendMessage: message can be string or Part[]
   if ('message' in params) {
-    const message = params.message;
-    const truncatedMessage = getTruncatedJsonString(message);
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: truncatedMessage });
+    messages.push({
+      role: 'user',
+      content: getTruncatedJsonString(params.message),
+    });
   }
 
   // For chats.create: history contains the conversation history
   if ('history' in params) {
-    const history = params.history;
-    const truncatedHistory = getTruncatedJsonString(history);
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: truncatedHistory });
+    messages.push({
+      role: 'user',
+      content: getTruncatedJsonString(params.history),
+    });
   }
+
+  span.setAttributes({
+    [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(messages),
+    [GEN_AI_RESPONSE_MODEL_ATTRIBUTE]: String(params.model),
+  });
 }
 
 /**