fix(server): preserve reasoning effort after restart

apps/server/integration/orphanedProviderSessionStartup.integration.test.ts

@@ -374,6 +374,11 @@ it.effect.each(["opt-in desktop restart", "marked remote update"] as const)(
       const activeTurnId = TurnId.make("turn-started-after-original-send");
       const originalTurnId = TurnId.make("turn-from-original-send");
       const sent = yield* Deferred.make<ProviderSendTurnInput>();
+      const modelSelection = {
+        instanceId: providerInstanceId,
+        model: "gpt-5",
+        options: [{ id: "reasoningEffort", value: "high" }],
+      };
 
       yield* Effect.gen(function* () {
         const engine = yield* OrchestrationEngine.OrchestrationEngineService;
@@ -384,7 +389,7 @@ it.effect.each(["opt-in desktop restart", "marked remote update"] as const)(
           projectId,
           title: "Restart continuation",
           workspaceRoot: "/tmp/startup-orphan-project",
-          defaultModelSelection: { instanceId: providerInstanceId, model: "gpt-5" },
+          defaultModelSelection: modelSelection,
           createdAt,
         });
         yield* engine.dispatch({
@@ -393,7 +398,7 @@ it.effect.each(["opt-in desktop restart", "marked remote update"] as const)(
           threadId,
           projectId,
           title: "Newer running turn",
-          modelSelection: { instanceId: providerInstanceId, model: "gpt-5" },
+          modelSelection,
           interactionMode: DEFAULT_PROVIDER_INTERACTION_MODE,
           runtimeMode: "full-access",
           branch: null,
@@ -469,6 +474,7 @@ it.effect.each(["opt-in desktop restart", "marked remote update"] as const)(
         assert.deepStrictEqual(yield* Deferred.await(sent), {
           threadId,
           continuation: true,
+          modelSelection,
           interactionMode: DEFAULT_PROVIDER_INTERACTION_MODE,
         });
       }).pipe(

apps/server/src/provider/Layers/CodexSessionRuntime.test.ts

@@ -179,6 +179,26 @@ describe("buildTurnStartParams", () => {
     });
   });
 
+  it.effect("preserves a non-default reasoning effort in collaboration mode", () =>
+    Effect.gen(function* () {
+      const params = yield* buildTurnStartParams({
+        threadId: "provider-thread-1",
+        runtimeMode: "full-access",
+        prompt: "Continue the task",
+        model: "gpt-5.3-codex",
+        effort: "high",
+        interactionMode: "default",
+      });
+
+      NodeAssert.equal(params.effort, "high");
+      NodeAssert.equal(params.collaborationMode?.settings.reasoning_effort, "high");
+      NodeAssert.match(
+        params.collaborationMode?.settings.developer_instructions ?? "",
+        /with high reasoning effort/,
+      );
+    }),
+  );
+
   it("reports the same fallback model and effort in settings and instructions", () => {
     const params = Effect.runSync(
       buildTurnStartParams({

apps/server/src/serverRuntimeStartup.reconcile.test.ts

@@ -41,6 +41,11 @@ const makeThread = (
   id: ThreadId.make(id),
   archivedAt,
   deletedAt,
+  modelSelection: {
+    instanceId: providerInstanceId,
+    model: "gpt-5.3-codex",
+    options: [{ id: "reasoningEffort", value: "high" }],
+  },
   interactionMode: "default" as const,
   session: {
     threadId: ThreadId.make(id),
@@ -304,10 +309,16 @@ it.effect.each(
           String(left.threadId).localeCompare(String(right.threadId)),
         ),
         [
-          { threadId: codex.id, continuation: true, interactionMode: "default" },
+          {
+            threadId: codex.id,
+            continuation: true,
+            modelSelection: codex.modelSelection,
+            interactionMode: "default",
+          },
           {
             threadId: fallback.id,
             input: "Continue where you left off.",
+            modelSelection: fallback.modelSelection,
             interactionMode: "default",
           },
         ],
@@ -906,7 +917,12 @@ for (const preparedStatus of [
       yield* runReconciliation(input);
       yield* Deferred.await(cleared);
       assert.deepStrictEqual(sends, [
-        { threadId: thread.id, continuation: true, interactionMode: "default" },
+        {
+          threadId: thread.id,
+          continuation: true,
+          modelSelection: thread.modelSelection,
+          interactionMode: "default",
+        },
       ]);
       assert.deepStrictEqual(binding.runtimePayload, {
         activeTurnId: null,

apps/server/src/serverRuntimeStartup.ts

@@ -694,6 +694,7 @@ export const reconcileProviderSessions = Effect.gen(function* () {
               ...(capabilities.promptlessTurnContinuation === true
                 ? { continuation: true }
                 : { input: SERVER_UPDATE_CONTINUATION_PROMPT }),
+              modelSelection: thread.modelSelection,
               interactionMode: thread.interactionMode,
             });
           });