harden retrieval logic

bugfixes

src/Agent/PromptBuilder.php

@@ -42,6 +42,13 @@ final readonly class PromptBuilder
      */
     private const MIN_PROMPT_BUDGET_TOKENS = 1024;
 
+    /**
+     * Limit how many ranked shop results are passed into the final prompt.
+     * The shop search may return many candidates, but the LLM should only see
+     * the most relevant top subset after local reranking.
+     */
+    private const MAX_SHOP_RESULTS_IN_PROMPT = 8;
+
     /**
      * Technical product prompts should be answered like documentation,
      * not like sales copy.
@@ -84,8 +91,7 @@ final readonly class PromptBuilder
         private ContextService $contextService,
         private SystemPromptRepository $systemPromptRepository,
         private ModelGenerationConfigProvider $modelGenerationConfigProvider,
-    )
-    {
+    ) {
     }
 
     /**
@@ -222,18 +228,21 @@ final readonly class PromptBuilder
                 "Source: Shop Search";
         }
 
-        if ($shopResults === []) {
+        $normalizedShopResults = array_values(array_filter(
+            $shopResults,
+            static fn(mixed $product): bool => $product instanceof ShopProductResult
+        ));
+
+        if ($normalizedShopResults === []) {
             return $this->implodeBlocks($parts);
         }
 
-        $isDetailed = count($shopResults) <= 5;
+        $totalCount = count($normalizedShopResults);
+        $limitedShopResults = array_slice($normalizedShopResults, 0, self::MAX_SHOP_RESULTS_IN_PROMPT);
+        $isDetailed = count($limitedShopResults) <= 5;
         $lines = [];
 
-        foreach ($shopResults as $i => $product) {
-            if (!$product instanceof ShopProductResult) {
-                continue;
-            }
-
+        foreach ($limitedShopResults as $i => $product) {
             $n = $i + 1;
             $entryParts = [
                 "[{$n}] " . $this->normalizeBlockText($product->name),
@@ -283,13 +292,19 @@ final readonly class PromptBuilder
         }
 
         if ($lines !== []) {
-            $parts[] =
+            $header =
                 "LIVE SHOP RESULTS (authoritative for current commercial details):\n" .
                 "Use these results as the primary source for current price, availability, URL, and current shop-visible product naming.\n" .
                 "If retrieved documents conflict with shop data on price, availability, URL, or current naming, prefer the shop data.\n" .
                 "Output real URL values exactly as provided in the shop results. Do not replace them with placeholders, link labels, or product names.\n" .
-                "Do not infer undocumented technical specifications from shop data.\n\n" .
-                implode("\n\n", $lines);
+                "Do not infer undocumented technical specifications from shop data.";
+
+            if ($totalCount > count($limitedShopResults)) {
+                $header .= "\n" .
+                    "Only the top " . count($limitedShopResults) . " ranked shop results are shown here out of {$totalCount} total results.";
+            }
+
+            $parts[] = $header . "\n\n" . implode("\n\n", $lines);
         }
 
         return $this->implodeBlocks($parts);