diff --git a/apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.test.ts b/apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.test.ts
index 8a68e92b89..8b8c4c6bee 100644
--- a/apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.test.ts
+++ b/apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.test.ts
@@ -4009,6 +4009,71 @@ describe("AcpAdapterV2", () => {
     }).pipe(Effect.provide(layerTest), Effect.scoped),
   );
 
+  it.effect("SCRATCH-27022 model set requests", () =>
+    Effect.gen(function* () {
+      const childProcessSpawner = yield* ChildProcessSpawner.ChildProcessSpawner;
+      const path = yield* Path.Path;
+      const selfInvocation = yield* resolveSelfInvocation();
+      const mockAgentPath = yield* path.fromFileUrl(
+        new URL("../../../scripts/acp-mock-agent.ts", import.meta.url),
+      );
+      const protocolEvents = yield* Queue.bounded<EffectAcpProtocol.AcpProtocolLogEvent>(1024);
+      const instanceId = ProviderInstanceId.make("acp-test");
+      const adapter = yield* makeAcpAdapterV2({
+        instanceId,
+        flavor: {
+          driver: ACP_TEST_DRIVER,
+          capabilities: AcpProviderCapabilitiesV2,
+          makeRuntime: makeMockRuntime({ childProcessSpawner, mockAgentPath, protocolEvents }),
+        },
+        selfInvocation,
+      });
+      const threadId = ThreadId.make("thread-scratch-27022");
+      const runtimePolicy = ProviderAdapter.ProviderAdapterV2RuntimePolicy.make({
+        runtimeMode: "full-access",
+        interactionMode: "default",
+        cwd: process.cwd(),
+      });
+      const sentModels = Effect.map(Queue.takeAll(protocolEvents), (events) =>
+        Array.from(events)
+          .filter(
+            (event) =>
+              event.direction === "outgoing" &&
+              (rawProtocolMethod(event) === "session/set_model" ||
+                (rawProtocolMethod(event) === "session/set_config_option" &&
+                  rawProtocolRequestParam(event, "configId") === "model")),
+          )
+          .map((event) => rawProtocolMethod(event) + "=" + String(rawProtocolRequestParam(event, "value") ?? rawProtocolRequestParam(event, "modelId"))),
+      ).pipe(Effect.tap(() => Effect.void));
+      const allOut = Effect.map(Queue.takeAll(protocolEvents), (events) =>
+        Array.from(events).filter((e) => e.direction === "outgoing").map((e) => String(rawProtocolMethod(e)) + ":" + String(rawProtocolRequestParam(e, "configId") ?? "") + "=" + String(rawProtocolRequestParam(e, "value") ?? rawProtocolRequestParam(e, "modelId") ?? "")),
+      );
+      const sel = (model: string) => ({ instanceId, model }) satisfies ModelSelection;
+      const runtime = yield* adapter.openSession({
+        threadId,
+        providerSessionId: ProviderSessionId.make("provider-session-scratch-27022"),
+        modelSelection: sel("default"),
+        runtimePolicy,
+      });
+      const providerThread = yield* runtime.ensureThread({ threadId, modelSelection: sel("default"), runtimePolicy });
+      const turn = (model: string) =>
+        Effect.gen(function* () {
+          yield* runtime.startTurn(
+            makeTurnInput({ threadId, providerThread, instanceId, runtimePolicy, modelSelection: sel(model), now: yield* DateTime.now }),
+          );
+          yield* runtime.events.pipe(Stream.filter((event) => event.type === "turn.terminal"), Stream.runHead);
+        });
+      const afterOpen = yield* allOut;
+      yield* turn("default");
+      const afterSameTurn = yield* allOut;
+      yield* turn("composer-2");
+      const afterSwitch = yield* allOut;
+      yield* turn("composer-2");
+      const afterSameAgain = yield* allOut;
+      require("node:fs").writeFileSync("/tmp/issue-lead-27022-r1/scratch-result.json", JSON.stringify({ afterOpen, afterSameTurn, afterSwitch, afterSameAgain }, null, 1));
+    }).pipe(Effect.provide(layerTest), Effect.scoped),
+  );
+
   it.live("terminalizes an empty successful foreground Bash tool when the turn completes", () =>
     Effect.gen(function* () {
       const childProcessSpawner = yield* ChildProcessSpawner.ChildProcessSpawner;