diff --git a/src/app/api/tools/agent-bridge/agents/[id]/dns/route.ts b/src/app/api/tools/agent-bridge/agents/[id]/dns/route.ts
index 368f8bcded..fa7f5f6abc 100644
--- a/src/app/api/tools/agent-bridge/agents/[id]/dns/route.ts
+++ b/src/app/api/tools/agent-bridge/agents/[id]/dns/route.ts
@@ -13,10 +13,10 @@ import { sanitizeErrorMessage } from "@omniroute/open-sse/utils/error";
 import { createErrorResponse } from "@/lib/api/errorResponse";
 import { ALL_TARGETS } from "@/mitm/targets/index";
 
-type Params = { params: { id: string } };
+type Params = { params: Promise<{ id: string }> };
 
 export async function POST(request: Request, { params }: Params): Promise<Response> {
-  const { id } = params;
+  const { id } = await params;
 
   let body: unknown;
   try {
diff --git a/tests/unit/agent-bridge-dns-params-7271.test.ts b/tests/unit/agent-bridge-dns-params-7271.test.ts
new file mode 100644
index 0000000000..013d5ade89
--- /dev/null
+++ b/tests/unit/agent-bridge-dns-params-7271.test.ts
@@ -0,0 +1,37 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { POST } from "../../src/app/api/tools/agent-bridge/agents/[id]/dns/route.ts";
+
+/**
+ * Regression for #7271: Agent Bridge "Start DNS" returned HTTP 404.
+ *
+ * Next.js 16 makes a dynamic route's `params` a Promise. The handler destructured
+ * `id` directly from the (un-awaited) Promise, so `id` was `undefined` and the
+ * agent lookup always missed — producing `404 Unknown agent: undefined` for every
+ * request, including valid agents.
+ *
+ * This test drives the handler with the Next.js 16 params shape (a Promise) and an
+ * unknown agent id. It never reaches the DNS side-effects (the 404 fires before
+ * `addDNSEntry`), so it is a pure, side-effect-free reproduction: the 404 message
+ * must echo the *resolved* id — proving `params` was awaited — not `undefined`.
+ */
+test("POST /agents/[id]/dns awaits params — 404 echoes the real id, not 'undefined'", async () => {
+  const agentId = "definitely-not-a-real-agent-7271";
+  const request = new Request("http://localhost/api/tools/agent-bridge/agents/x/dns", {
+    method: "POST",
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify({ enabled: false }),
+  });
+
+  const res = await POST(request, { params: Promise.resolve({ id: agentId }) });
+  const body = await res.json();
+
+  assert.equal(res.status, 404);
+  // Before the fix, `id` was `undefined`, so the message read "Unknown agent: undefined".
+  assert.equal(body.error.message, `Unknown agent: ${agentId}`);
+  assert.ok(
+    !body.error.message.includes("undefined"),
+    "params must be awaited — message should not contain 'undefined'"
+  );
+});