⚡ Bolt: optimize prompt evaluation loop to skip redundant calls (#152)

- Avoid re-evaluating the current prompt if metrics are already available from the previous iteration.
- Pass metrics from the best variation to the next iteration.
- Reduces N-1 expensive LLM calls in an N-iteration optimization loop.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

plugins/llm-application-dev/skills/prompt-engineering-patterns/scripts/optimize-prompt.py

@@ -106,12 +106,18 @@ class PromptOptimizer:
         current_prompt = base_prompt
         best_prompt = base_prompt
         best_score = 0
+        current_metrics = None
 
         for iteration in range(max_iterations):
             print(f"\nIteration {iteration + 1}/{max_iterations}")
 
             # Evaluate current prompt
+            # Bolt Optimization: Avoid re-evaluating if we already have metrics from previous iteration
+            if current_metrics:
+                metrics = current_metrics
+            else:
                 metrics = self.evaluate_prompt(current_prompt)
+
             print(f"Accuracy: {metrics['avg_accuracy']:.2f}, Latency: {metrics['avg_latency']:.2f}s")
 
             # Track results
@@ -137,14 +143,17 @@ class PromptOptimizer:
             # Test variations and pick best
             best_variation = current_prompt
             best_variation_score = metrics['avg_accuracy']
+            best_variation_metrics = metrics
 
             for variation in variations:
                 var_metrics = self.evaluate_prompt(variation)
                 if var_metrics['avg_accuracy'] > best_variation_score:
                     best_variation_score = var_metrics['avg_accuracy']
                     best_variation = variation
+                    best_variation_metrics = var_metrics
 
             current_prompt = best_variation
+            current_metrics = best_variation_metrics
 
         return {
             'best_prompt': best_prompt,