fix(server): a Claude model change no longer blocks the next provider switch

apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts

@@ -6555,6 +6555,52 @@ describe("ClaudeAdapterV2 background wake turns", () => {
     ),
   );
 
+  it.effect("does not count a live model change's stdout echo as background work", () =>
+    Effect.scoped(
+      Effect.gen(function* () {
+        const harness = yield* makeWakeHarness;
+        yield* harness.runtime.startTurn(
+          makeClaudeTestTurnInput({
+            threadId: harness.threadId,
+            providerThread: harness.providerThread,
+            now: yield* DateTime.now,
+            attemptId: RunAttemptId.make("attempt-model-change-echo"),
+            text: "Hello",
+            attachments: [],
+          }),
+        );
+        yield* harness.offerAndWait(turnOneResult);
+        yield* Queue.take(harness.terminalReceipts);
+
+        // Claude Code answers set_model with this replayed user frame before the next turn attaches.
+        yield* harness.offerAndWait(
+          claudeSdkFrame({
+            type: "user",
+            message: {
+              role: "user",
+              content:
+                "<local-command-stdout>Set model to `claude-fable-5-2`</local-command-stdout>",
+            },
+            parent_tool_use_id: null,
+            isReplay: true,
+            uuid: "00000000-0000-4000-8000-000000000e01",
+            session_id: WAKE_NATIVE_SESSION,
+          }),
+        );
+        assert.isFalse(yield* harness.hasPendingBackgroundWork);
+      }).pipe(
+        Effect.provide(
+          Layer.mergeAll(
+            IdAllocator.layer,
+            McpProviderSessions.layer,
+            NodeServices.layer,
+            NodeCrypto.layer,
+          ),
+        ),
+      ),
+    ),
+  );
+
   it.effect.each([
     {
       content: { type: "advisor_tool_result_error", error_code: "overloaded" },

apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts

@@ -3618,6 +3618,17 @@ function isClaudeTurnStartMessage(message: SDKMessage): boolean {
   return message.type === "system" && message.subtype === "init";
 }
 
+// Claude Code replays a local command's stdout, such as set_model's "Set model to", as a user frame.
+function isClaudeLocalCommandEcho(message: SDKMessage): boolean {
+  return (
+    message.type === "user" &&
+    "isReplay" in message &&
+    message.isReplay === true &&
+    typeof message.message.content === "string" &&
+    message.message.content.startsWith("<local-command-stdout>")
+  );
+}
+
 function isClaudeRootTurnFrame(message: SDKMessage): boolean {
   return (
     isClaudeTurnStartMessage(message) ||
@@ -9374,6 +9385,8 @@ export const makeClaudeAdapterV2 = Effect.fn("makeClaudeAdapterV2")(function* (
           readonly message: SDKMessage;
         }) {
           const message = wakeInput.message;
+          // An idle echo is no wake: buffered, it reads as background work and blocks switches.
+          if (isClaudeLocalCommandEcho(message)) return;
           const isNotification =
             message.type === "system" && message.subtype === "task_notification";
           const isPendingTaskNotification =