fix(gateway): ack agent requests immediately

src/gateway/server.test.ts

@@ -481,7 +481,7 @@ describe("gateway server", () => {
     await server.close();
   });
 
-  test("agent ack event then final response", { timeout: 8000 }, async () => {
+  test("agent ack response then final response", { timeout: 8000 }, async () => {
     const { server, ws } = await startServerWithClient();
     ws.send(
       JSON.stringify({
@@ -502,11 +502,13 @@ describe("gateway server", () => {
     const ackP = onceMessage(
       ws,
       (o) =>
-        o.type === "event" &&
-        o.event === "agent" &&
-        o.payload?.status === "accepted",
+        o.type === "res" && o.id === "ag1" && o.payload?.status === "accepted",
+    );
+    const finalP = onceMessage(
+      ws,
+      (o) =>
+        o.type === "res" && o.id === "ag1" && o.payload?.status !== "accepted",
     );
-    const finalP = onceMessage(ws, (o) => o.type === "res" && o.id === "ag1");
     ws.send(
       JSON.stringify({
         type: "req",
@@ -732,7 +734,8 @@ describe("gateway server", () => {
     const ws1 = await dial();
     const final1P = onceMessage(
       ws1,
-      (o) => o.type === "res" && o.id === "ag1",
+      (o) =>
+        o.type === "res" && o.id === "ag1" && o.payload?.status !== "accepted",
       6000,
     );
     ws1.send(
@@ -749,7 +752,8 @@ describe("gateway server", () => {
     const ws2 = await dial();
     const final2P = onceMessage(
       ws2,
-      (o) => o.type === "res" && o.id === "ag2",
+      (o) =>
+        o.type === "res" && o.id === "ag2" && o.payload?.status !== "accepted",
       6000,
     );
     ws2.send(

src/gateway/server.ts

@@ -1208,22 +1208,17 @@ export async function startGatewayServer(
 
             const deliver =
               params.deliver === true && resolvedChannel !== "webchat";
-            // Acknowledge via event to avoid double res frames
-            const ackEvent = {
-              type: "event",
-              event: "agent",
-              payload: { runId, status: "accepted" as const },
-              seq: ++seq,
-            };
-            socket.send(JSON.stringify(ackEvent));
-            logWs("out", "event", {
-              connId,
-              event: "agent",
-              runId,
-              status: "accepted",
+
+            const accepted = { runId, status: "accepted" as const };
+            // Store an in-flight ack so retries do not spawn a second run.
+            dedupe.set(`agent:${idem}`, {
+              ts: Date.now(),
+              ok: true,
+              payload: accepted,
             });
-            try {
-              await agentCommand(
+            respond(true, accepted, undefined, { runId });
+
+            void agentCommand(
               {
                 message,
                 to: resolvedTo,
@@ -1237,7 +1232,8 @@ export async function startGatewayServer(
               },
               defaultRuntime,
               deps,
-              );
+            )
+              .then(() => {
                 const payload = {
                   runId,
                   status: "ok" as const,
@@ -1248,8 +1244,11 @@ export async function startGatewayServer(
                   ok: true,
                   payload,
                 });
+                // Send a second res frame (same id) so TS clients with expectFinal can wait.
+                // Swift clients will typically treat the first res as the result and ignore this.
                 respond(true, payload, undefined, { runId });
-            } catch (err) {
+              })
+              .catch((err) => {
                 const error = errorShape(ErrorCodes.UNAVAILABLE, String(err));
                 const payload = {
                   runId,
@@ -1266,7 +1265,7 @@ export async function startGatewayServer(
                   runId,
                   error: formatForLog(err),
                 });
-            }
+              });
             break;
           }
           default: {