diff --git a/src/app-server.mjs b/src/app-server.mjs
index f8e8357..35303db 100644
--- a/src/app-server.mjs
+++ b/src/app-server.mjs
@@ -1026,8 +1026,8 @@ export class CodexAppServer {
       case "feedback/upload": return this.#feedbackUpload();
       case "config/value/write":
       case "config/batchWrite":
-      case "remoteControl/enable": return {};
       case "config/write": return this.#configWrite(params);
+      case "remoteControl/enable": return {};
       case "config/read": return this.#configRead(params);
       case "features/list": return this.#featuresList();
       case "thread/start": return this.#threadStart(peer, params);
diff --git a/test/app-server.test.mjs b/test/app-server.test.mjs
index 0b0fc02..1d02bc1 100644
--- a/test/app-server.test.mjs
+++ b/test/app-server.test.mjs
@@ -191,6 +191,34 @@ test("initialization and model discovery", () => withHarness({}, async (h) => {
   assert.deepEqual(await h.request("remoteControl/enable", { enabled: true }), {});
 }));
 
+test("new-thread model picker writes update the defaults used by thread/start", () => withHarness({
+  config: { defaultModel: "mock/omp", defaultReasoningEffort: "medium" },
+}, async (h) => {
+  await h.initialize();
+  const result = await h.request("config/batchWrite", {
+    edits: [
+      { keyPath: "model", value: "claude-opus-5", mergeStrategy: "upsert" },
+      { keyPath: "model_reasoning_effort", value: "xhigh", mergeStrategy: "upsert" },
+    ],
+    filePath: null,
+    expectedVersion: null,
+    reloadUserConfig: true,
+  });
+  assert.equal(result.status, "ok");
+
+  const { config } = await h.request("config/read", { cwd: h.temp });
+  assert.equal(config.model, "claude-opus-5");
+  assert.equal(config.model_reasoning_effort, "xhigh");
+
+  const { thread } = await h.request("thread/start", { cwd: h.temp });
+  assert.equal(thread.model, "claude-opus-5");
+  assert.equal(thread.reasoningEffort, "xhigh");
+
+  const persisted = JSON.parse(await fs.readFile(path.join(h.temp, "config.json"), "utf8"));
+  assert.equal(persisted.defaultModel, "claude-opus-5");
+  assert.equal(persisted.defaultReasoningEffort, "xhigh");
+}));
+
 test("fuzzy file search supports single-shot and streaming mention completion", () => withHarness({}, async (h) => {
   await h.initialize();
   await fs.mkdir(path.join(h.temp, "src"), { recursive: true });