1.5The History Buffer

The history buffer is critical for preventing infinite loops and enabling learning within a test run.

# Keep the last N steps to fit in context window
self.history = self.history[-5:]

# Each history entry includes:
{
    "step": 3,
    "observation": "Page shows login form with email/password fields",
    "decision": "TYPE input[name=email] test@example.com",
    "result": "success"
}

Without history: The agent might click the same button repeatedly, not remembering it already tried that.

With history: The agent reasons, "I already tried clicking the submit button and it did not navigate. Let me check if there is a validation error I missed."