SerpAPI not triggered and inconsistent output from AI Agent

Workflow executes without calling SerpAPI, and the AI Agent returns inconsistent or variable outputs instead of expected results.

n8n:

Payload:
{ "prompt": "Who is Mathesh Natarajan?" }
File:

SerpAPI : 67cd6b0c28aaa78a590394c7f5215c5574341fed4fe550c775f5b59e0471c860