diff --git a/RETRIEX_P29_SHOP_RESULT_DEDUPE_HARDENING_README.md b/RETRIEX_P29_SHOP_RESULT_DEDUPE_HARDENING_README.md
new file mode 100644
index 0000000..c482f1b
--- /dev/null
+++ b/RETRIEX_P29_SHOP_RESULT_DEDUPE_HARDENING_README.md
@@ -0,0 +1,18 @@
+# RetrieX p29 - Shop Result Dedupe Hardening
+
+Purpose:
+- Prevent repeated shop product records from being passed into prompts or rendered in fallback output.
+- Treat product number as the strongest deduplication key, so SKU variants with slightly different display names do not appear repeatedly.
+- Keep the existing shop ranking and technical suitability logic unchanged.
+
+Changed files:
+- `src/Commerce/ShopSearchService.php`
+- `src/Agent/PromptBuilder.php`
+
+Validation:
+```bash
+bin/console mto:agent:config:validate
+bin/console mto:agent:regression:test
+bin/console mto:agent:config:audit-source --details
+bin/console mto:agent:config:audit-patterns --details
+```
diff --git a/src/Agent/PromptBuilder.php b/src/Agent/PromptBuilder.php
index fceb9d1..9d964c8 100644
--- a/src/Agent/PromptBuilder.php
+++ b/src/Agent/PromptBuilder.php
@@ -202,10 +202,10 @@ final readonly class PromptBuilder
             ]);
         }
 
-        $normalizedShopResults = array_values(array_filter(
+        $normalizedShopResults = $this->deduplicateShopResultsForPrompt(array_values(array_filter(
             $shopResults,
             static fn(mixed $product): bool => $product instanceof ShopProductResult
-        ));
+        )));
 
         if ($normalizedShopResults === []) {
             return $this->implodeBlocks($parts);
@@ -1174,6 +1174,81 @@ final readonly class PromptBuilder
         return false;
     }
 
+    /**
+     * @param ShopProductResult[] $shopResults
+     * @return ShopProductResult[]
+     */
+    private function deduplicateShopResultsForPrompt(array $shopResults): array
+    {
+        $unique = [];
+        $seen = [];
+
+        foreach ($shopResults as $product) {
+            $keys = $this->buildShopResultPromptDeduplicationKeys($product);
+
+            if ($keys === []) {
+                $unique[] = $product;
+                continue;
+            }
+
+            $isDuplicate = false;
+            foreach ($keys as $key) {
+                if (isset($seen[$key])) {
+                    $isDuplicate = true;
+                    break;
+                }
+            }
+
+            if ($isDuplicate) {
+                continue;
+            }
+
+            foreach ($keys as $key) {
+                $seen[$key] = true;
+            }
+
+            $unique[] = $product;
+        }
+
+        return $unique;
+    }
+
+    /**
+     * @return string[]
+     */
+    private function buildShopResultPromptDeduplicationKeys(ShopProductResult $product): array
+    {
+        $productNumber = $this->normalizeShopResultDeduplicationValue((string) ($product->productNumber ?? ''));
+        if ($productNumber !== '') {
+            return ['number|' . $productNumber];
+        }
+
+        $id = $this->normalizeShopResultDeduplicationValue($product->id);
+        if ($id !== '') {
+            return ['id|' . $id];
+        }
+
+        $url = $this->normalizeShopResultDeduplicationValue((string) ($product->url ?? ''));
+        if ($url !== '') {
+            return ['url|' . $url];
+        }
+
+        $name = $this->normalizeShopResultDeduplicationValue($product->name);
+        if ($name !== '') {
+            return ['name|' . $name];
+        }
+
+        return [];
+    }
+
+    private function normalizeShopResultDeduplicationValue(string $value): string
+    {
+        $value = mb_strtolower(trim($value), 'UTF-8');
+        $value = preg_replace('/\s+/u', ' ', $value) ?? $value;
+
+        return trim($value);
+    }
+
     private function normalizeNullableBlockText(?string $value): ?string
     {
         if ($value === null) {
@@ -1233,4 +1308,4 @@ final readonly class PromptBuilder
     {
         return max($min, min($max, $value));
     }
-}
\ No newline at end of file
+}
diff --git a/src/Commerce/ShopSearchService.php b/src/Commerce/ShopSearchService.php
index b5baa08..43b1016 100644
--- a/src/Commerce/ShopSearchService.php
+++ b/src/Commerce/ShopSearchService.php
@@ -1665,21 +1665,70 @@ final class ShopSearchService
         $seen = [];
 
         foreach ($products as $product) {
-            $key = mb_strtolower(trim(implode($this->shopConfig->getDeduplicationSeparator(), [
-                $product->id,
-                $product->productNumber ?? '',
-                $product->name,
-                $product->url ?? '',
-            ])), 'UTF-8');
+            $keys = $this->buildProductDeduplicationKeys($product);
 
-            if (isset($seen[$key])) {
+            if ($keys === []) {
+                $unique[] = $product;
                 continue;
             }
 
-            $seen[$key] = true;
+            $isDuplicate = false;
+            foreach ($keys as $key) {
+                if (isset($seen[$key])) {
+                    $isDuplicate = true;
+                    break;
+                }
+            }
+
+            if ($isDuplicate) {
+                continue;
+            }
+
+            foreach ($keys as $key) {
+                $seen[$key] = true;
+            }
+
             $unique[] = $product;
         }
 
         return $unique;
     }
-}
\ No newline at end of file
+
+    /**
+     * @return string[]
+     */
+    private function buildProductDeduplicationKeys(ShopProductResult $product): array
+    {
+        $separator = $this->shopConfig->getDeduplicationSeparator();
+
+        $productNumber = $this->normalizeDeduplicationValue($product->productNumber ?? '');
+        if ($productNumber !== '') {
+            return ['number' . $separator . $productNumber];
+        }
+
+        $id = $this->normalizeDeduplicationValue($product->id);
+        if ($id !== '') {
+            return ['id' . $separator . $id];
+        }
+
+        $url = $this->normalizeDeduplicationValue((string) ($product->url ?? ''));
+        if ($url !== '') {
+            return ['url' . $separator . $url];
+        }
+
+        $name = $this->normalizeDeduplicationValue($product->name);
+        if ($name !== '') {
+            return ['name' . $separator . $name];
+        }
+
+        return [];
+    }
+
+    private function normalizeDeduplicationValue(string $value): string
+    {
+        $value = mb_strtolower(trim($value), 'UTF-8');
+        $value = preg_replace($this->shopConfig->getWhitespaceCollapsePattern(), ' ', $value) ?? $value;
+
+        return trim($value);
+    }
+}