diff --git a/mem0-ts/src/oss/src/memory/index.ts b/mem0-ts/src/oss/src/memory/index.ts
index a8dde5d01..f41d161ac 100644
--- a/mem0-ts/src/oss/src/memory/index.ts
+++ b/mem0-ts/src/oss/src/memory/index.ts
@@ -750,7 +750,13 @@ export class Memory {
         // getLastMessages not supported — proceed without context
       }
     }
-    const parsedMessages = messages.map((m) => m.content).join("\n");
+    // Preserve role on the messages being extracted so the prompt's role-aware
+    // logic and the required `attributed_to` output have the speaker to work
+    // with. Matches the Python oss `parse_messages` helper (`role: content`);
+    // without this, assistant statements get attributed to the user.
+    const parsedMessages = messages
+      .map((m) => `${m.role}: ${m.content}`)
+      .join("\n");
 
     // Phase 1: Existing memory retrieval
     const queryEmbedding = await this.embedder.embed(parsedMessages);
diff --git a/mem0-ts/src/oss/tests/memory.add.test.ts b/mem0-ts/src/oss/tests/memory.add.test.ts
index f3c637e5a..4e7ebe773 100644
--- a/mem0-ts/src/oss/tests/memory.add.test.ts
+++ b/mem0-ts/src/oss/tests/memory.add.test.ts
@@ -126,6 +126,22 @@ describe("Memory - add()", () => {
     expect(result.results.length).toBeGreaterThan(0);
   });
 
+  test("preserves message roles in the extraction prompt (## New Messages)", async () => {
+    // The OpenAI LLM mock echoes the `## New Messages` section of the prompt back
+    // as the extracted text, so the stored memory reveals what the LLM received.
+    // Roles must survive into that section, otherwise the prompt's role-aware
+    // logic and required `attributed_to` output have no speaker to attribute to
+    // and assistant statements get stored as user facts.
+    const messages = [
+      { role: "user", content: "I want to sleep earlier." },
+      { role: "assistant", content: "Aim for 00:30 sleep / 08:30 wake." },
+    ];
+    const result: SearchResult = await memory.add(messages, { userId });
+    const seen = result.results.map((r) => r.memory).join("\n");
+    expect(seen).toContain("user: I want to sleep earlier.");
+    expect(seen).toContain("assistant: Aim for 00:30 sleep / 08:30 wake.");
+  });
+
   test("works with agentId instead of userId", async () => {
     const result: SearchResult = await memory.add("test", {
       agentId: "agent_1",