diff --git a/backend/src/lib/embeddings.ts b/backend/src/lib/embeddings.ts
index 0dcd448..54353ab 100644
--- a/backend/src/lib/embeddings.ts
+++ b/backend/src/lib/embeddings.ts
@@ -24,23 +24,9 @@ export async function embedText(text: string): Promise<number[] | null> {
 }
 
 /**
- * Compute cosine similarity between two embedding vectors.
- * Returns a value between -1 and 1 (1 = identical).
+ * Re-export cosine similarity from @bytelyst/palace shared primitives.
  */
-export function cosineSimilarity(a: number[], b: number[]): number {
-  if (a.length !== b.length || a.length === 0) return 0;
-  let dot = 0;
-  let magA = 0;
-  let magB = 0;
-  for (let i = 0; i < a.length; i++) {
-    dot += a[i] * b[i];
-    magA += a[i] * a[i];
-    magB += b[i] * b[i];
-  }
-  const denom = Math.sqrt(magA) * Math.sqrt(magB);
-  if (denom === 0) return 0;
-  return dot / denom;
-}
+export { cosineSimilarity } from '@bytelyst/palace';
 
 /**
  * Strip HTML and normalize whitespace for embedding input.