diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10f6ea8d10..a1522443af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- WhatsApp: preserve original filenames for inbound documents. (#12691) Thanks @akramcodez.
 - Telegram: harden quote parsing; preserve quote context; avoid QUOTE_TEXT_INVALID; avoid nested reply quote misclassification. (#12156) Thanks @rybnikov.
 - Telegram: recover proactive sends when stale topic thread IDs are used by retrying without `message_thread_id`. (#11620)
 - Telegram: render markdown spoilers with `<tg-spoiler>` HTML tags. (#11543) Thanks @ezhikkk.
diff --git a/src/web/inbound.media.test.ts b/src/web/inbound.media.test.ts
index 91e37a5b4f..d7f7530d5c 100644
--- a/src/web/inbound.media.test.ts
+++ b/src/web/inbound.media.test.ts
@@ -235,4 +235,45 @@ describe("web inbound media saves with extension", () => {
 
     await listener.close();
   });
+
+  it("passes document filenames to saveMediaBuffer", async () => {
+    const onMessage = vi.fn();
+    const listener = await monitorWebInbox({ verbose: false, onMessage });
+    const { createWaSocket } = await import("./session.js");
+    const realSock = await (
+      createWaSocket as unknown as () => Promise<{
+        ev: import("node:events").EventEmitter;
+      }>
+    )();
+
+    const fileName = "invoice.pdf";
+    const upsert = {
+      type: "notify",
+      messages: [
+        {
+          key: { id: "doc1", fromMe: false, remoteJid: "333@s.whatsapp.net" },
+          message: { documentMessage: { mimetype: "application/pdf", fileName } },
+          messageTimestamp: 1_700_000_004,
+        },
+      ],
+    };
+
+    realSock.ev.emit("messages.upsert", upsert);
+
+    for (let i = 0; i < 50; i++) {
+      if (onMessage.mock.calls.length > 0) {
+        break;
+      }
+      await new Promise((resolve) => setTimeout(resolve, 10));
+    }
+
+    expect(onMessage).toHaveBeenCalledTimes(1);
+    const msg = onMessage.mock.calls[0][0];
+    expect(msg.mediaFileName).toBe(fileName);
+    expect(saveMediaBufferSpy).toHaveBeenCalled();
+    const lastCall = saveMediaBufferSpy.mock.calls.at(-1);
+    expect(lastCall?.[4]).toBe(fileName);
+
+    await listener.close();
+  });
 });