Optional replyId on send (API + MCP) — protocol-level threaded replies (#31)

src/mesh/mesh.service.spec.ts

@@ -296,6 +296,64 @@ describe('MeshService send', () => {
       bridge.close();
     }
   });
+
+  it('sets Data.reply_id when replyId is given and leaves it unset otherwise', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      const out: Uint8Array[] = [];
+      bridge.sockets[0].on('data', (c) => out.push(c));
+      await svc.sendText(42, 'reply send', 42); // replyId = 42
+      await svc.sendText(43, 'plain send');
+
+      const readOutbound = (): P.Mesh.MeshPacket[] => {
+        const merged = new Uint8Array(out.reduce((n, c) => n + c.length, 0));
+        let off = 0;
+        for (const c of out) {
+          merged.set(c, off);
+          off += c.length;
+        }
+        const { packets } = extractFrames(merged);
+        // outbound starts with the want_config_id frame — collect only text packets, in order
+        return packets.flatMap((p) => {
+          const tr = fromBinary(P.Mesh.ToRadioSchema, p);
+          if (tr.payloadVariant?.case === 'packet')
+            return [tr.payloadVariant.value];
+          return [];
+        });
+      };
+
+      await waitFor(() => readOutbound().length === 2);
+      const [replyPkt, plainPkt] = readOutbound();
+      const replyData =
+        replyPkt.payloadVariant?.case === 'decoded'
+          ? replyPkt.payloadVariant.value
+          : undefined;
+      expect(
+        new TextDecoder().decode(replyData?.payload ?? new Uint8Array()),
+      ).toBe('reply send');
+      expect(replyData?.replyId).toBe(42); // threaded reply to packet 42
+
+      const plainData =
+        plainPkt.payloadVariant?.case === 'decoded'
+          ? plainPkt.payloadVariant.value
+          : undefined;
+      expect(
+        new TextDecoder().decode(plainData?.payload ?? new Uint8Array()),
+      ).toBe('plain send');
+      expect(plainData?.replyId).toBe(0); // omitted → proto3 default, not a reply
+    } finally {
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
 });
 
 describe('MeshService node database', () => {