fix: minor

Author: mmilanta

demo.py

@@ -7,15 +7,17 @@
 from invariant_sdk.client import Client as InvariantClient
 from dotenv import load_dotenv
 import sys
+import os
 load_dotenv()
 
 anthropic_client = Anthropic()
-invariant_client = InvariantClient()
+invariant_client = InvariantClient() if "INVARIANT_API_KEY" in os.environ else None
 
 async def run(playwright: Playwright, prompt: str):
     browser = await playwright.firefox.launch(headless=False)
     context = await browser.new_context()
     page = await context.new_page()
+    await page.set_viewport_size({"width": 1024, "height": 768}) # Computer-use default
     await page.goto("https://www.google.com")
     playwright_tools = PlaywrightToolbox(page, use_cursor=True)
     messages = await sampling_loop(
@@ -27,12 +29,15 @@ async def run(playwright: Playwright, prompt: str):
         verbose=True
     )
     print(messages[-1]["content"][0]["text"])
-    response = invariant_client.create_request_and_push_trace(
-        messages=[anthropic_to_invariant(messages)],
-        dataset="playwright_computer_use_trace"
-    )
-    url = f"{invariant_client.api_url}/trace/{response.id[0]}"
-    print(f"View the trace at {url}")
+    if invariant_client is not None:
+        response = invariant_client.create_request_and_push_trace(
+            messages=[anthropic_to_invariant(messages)],
+            dataset="playwright_computer_use_trace"
+        )
+        url = f"{invariant_client.api_url}/trace/{response.id[0]}"
+        print(f"View the trace at {url}")
+    else:
+        print("No INVARIANT_API_KEY found. Add it to your .env file to push the trace to Invariant explorer https://explorer.invariantlabs.ai.")
     await browser.close()
 
 prompt = sys.argv[1]