diff --git a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
index 2a72d59027..39f1376431 100644
--- a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
+++ b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
@@ -5,7 +5,6 @@ import {
   type OrchestrationEvent,
   type ProviderModelOptions,
   type ProviderKind,
-  type ProviderServiceTier,
   type ProviderStartOptions,
   type OrchestrationSession,
   ThreadId,
@@ -205,7 +204,6 @@ const make = Effect.gen(function* () {
       readonly provider?: ProviderKind;
       readonly model?: string;
       readonly modelOptions?: ProviderModelOptions;
-      readonly serviceTier?: ProviderServiceTier | null;
       readonly providerOptions?: ProviderStartOptions;
     },
   ) {
@@ -241,7 +239,6 @@ const make = Effect.gen(function* () {
           : {}),
         ...(effectiveCwd ? { cwd: effectiveCwd } : {}),
         ...(desiredModel ? { model: desiredModel } : {}),
-        ...(options?.serviceTier !== undefined ? { serviceTier: options.serviceTier } : {}),
         ...(options?.modelOptions !== undefined ? { modelOptions: options.modelOptions } : {}),
         ...(options?.providerOptions !== undefined ? { providerOptions: options.providerOptions } : {}),
         ...(input?.resumeCursor !== undefined ? { resumeCursor: input.resumeCursor } : {}),
@@ -328,7 +325,6 @@ const make = Effect.gen(function* () {
     readonly attachments?: ReadonlyArray<ChatAttachment>;
     readonly provider?: ProviderKind;
     readonly model?: string;
-    readonly serviceTier?: ProviderServiceTier | null;
     readonly modelOptions?: ProviderModelOptions;
     readonly providerOptions?: ProviderStartOptions;
     readonly interactionMode?: "default" | "plan";
@@ -344,7 +340,6 @@ const make = Effect.gen(function* () {
     yield* ensureSessionForThread(input.threadId, input.createdAt, {
       ...(input.provider !== undefined ? { provider: input.provider } : {}),
       ...(input.model !== undefined ? { model: input.model } : {}),
-      ...(input.serviceTier !== undefined ? { serviceTier: input.serviceTier } : {}),
       ...(input.modelOptions !== undefined ? { modelOptions: input.modelOptions } : {}),
       ...(input.providerOptions !== undefined ? { providerOptions: input.providerOptions } : {}),
     });
@@ -365,7 +360,6 @@ const make = Effect.gen(function* () {
       ...(normalizedInput ? { input: normalizedInput } : {}),
       ...(normalizedAttachments.length > 0 ? { attachments: normalizedAttachments } : {}),
       ...(modelForTurn !== undefined ? { model: modelForTurn } : {}),
-      ...(input.serviceTier !== undefined ? { serviceTier: input.serviceTier } : {}),
       ...(input.modelOptions !== undefined ? { modelOptions: input.modelOptions } : {}),
       ...(input.interactionMode !== undefined ? { interactionMode: input.interactionMode } : {}),
     });
@@ -480,7 +474,6 @@ const make = Effect.gen(function* () {
       ...(message.attachments !== undefined ? { attachments: message.attachments } : {}),
       ...(event.payload.provider !== undefined ? { provider: event.payload.provider } : {}),
       ...(event.payload.model !== undefined ? { model: event.payload.model } : {}),
-      ...(event.payload.serviceTier !== undefined ? { serviceTier: event.payload.serviceTier } : {}),
       ...(event.payload.modelOptions !== undefined ? { modelOptions: event.payload.modelOptions } : {}),
       ...(event.payload.providerOptions !== undefined ? { providerOptions: event.payload.providerOptions } : {}),
       interactionMode: event.payload.interactionMode,
@@ -639,9 +632,13 @@ const make = Effect.gen(function* () {
             return;
           }
           const cachedProviderOptions = threadProviderOptions.get(event.payload.threadId);
-          yield* ensureSessionForThread(event.payload.threadId, event.occurredAt, {
-            ...(cachedProviderOptions !== undefined ? { providerOptions: cachedProviderOptions } : {}),
-          });
+          yield* ensureSessionForThread(
+            event.payload.threadId,
+            event.occurredAt,
+            cachedProviderOptions !== undefined
+              ? { providerOptions: cachedProviderOptions }
+              : undefined,
+          );
           return;
         }
         case "thread.turn-start-requested":
diff --git a/apps/server/src/orchestration/decider.ts b/apps/server/src/orchestration/decider.ts
index 1c1ca4dd79..2218f88cf5 100644
--- a/apps/server/src/orchestration/decider.ts
+++ b/apps/server/src/orchestration/decider.ts
@@ -301,7 +301,6 @@ export const decideOrchestrationCommand = Effect.fn("decideOrchestrationCommand"
           messageId: command.message.messageId,
           ...(command.provider !== undefined ? { provider: command.provider } : {}),
           ...(command.model !== undefined ? { model: command.model } : {}),
-          ...(command.serviceTier !== undefined ? { serviceTier: command.serviceTier } : {}),
           ...(command.modelOptions !== undefined ? { modelOptions: command.modelOptions } : {}),
           ...(command.providerOptions !== undefined ? { providerOptions: command.providerOptions } : {}),
           assistantDeliveryMode: command.assistantDeliveryMode ?? DEFAULT_ASSISTANT_DELIVERY_MODE,
diff --git a/apps/server/src/provider/Layers/CodexAdapter.ts b/apps/server/src/provider/Layers/CodexAdapter.ts
index 9a6271b792..a31ba2907e 100644
--- a/apps/server/src/provider/Layers/CodexAdapter.ts
+++ b/apps/server/src/provider/Layers/CodexAdapter.ts
@@ -1354,7 +1354,6 @@ const makeCodexAdapter = (options?: CodexAdapterLiveOptions) =>
               threadId: input.threadId,
               ...(input.input !== undefined ? { input: input.input } : {}),
               ...(input.model !== undefined ? { model: input.model } : {}),
-              ...(input.serviceTier !== undefined ? { serviceTier: input.serviceTier } : {}),
               ...(input.modelOptions?.codex?.reasoningEffort !== undefined
                 ? { effort: input.modelOptions.codex.reasoningEffort }
                 : {}),
diff --git a/apps/web/src/appSettings.test.ts b/apps/web/src/appSettings.test.ts
index 5ab5d3c90a..6c6cbac495 100644
--- a/apps/web/src/appSettings.test.ts
+++ b/apps/web/src/appSettings.test.ts
@@ -4,8 +4,6 @@ import {
   getAppModelOptions,
   getSlashModelOptions,
   normalizeCustomModelSlugs,
-  resolveAppServiceTier,
-  shouldShowFastTierIcon,
   resolveAppModelSelection,
 } from "./appSettings";
 
@@ -84,22 +82,3 @@ describe("getSlashModelOptions", () => {
     expect(options.map((option) => option.slug)).toEqual(["openai/gpt-oss-120b"]);
   });
 });
-
-describe("resolveAppServiceTier", () => {
-  it("maps automatic to no override", () => {
-    expect(resolveAppServiceTier("auto")).toBeNull();
-  });
-
-  it("preserves explicit service tier overrides", () => {
-    expect(resolveAppServiceTier("fast")).toBe("fast");
-    expect(resolveAppServiceTier("flex")).toBe("flex");
-  });
-});
-
-describe("shouldShowFastTierIcon", () => {
-  it("shows the fast-tier icon only for gpt-5.4 on fast tier", () => {
-    expect(shouldShowFastTierIcon("gpt-5.4", "fast")).toBe(true);
-    expect(shouldShowFastTierIcon("gpt-5.4", "auto")).toBe(false);
-    expect(shouldShowFastTierIcon("gpt-5.3-codex", "fast")).toBe(false);
-  });
-});
diff --git a/apps/web/src/appSettings.ts b/apps/web/src/appSettings.ts
index e58f7af4a6..5ed218fb25 100644
--- a/apps/web/src/appSettings.ts
+++ b/apps/web/src/appSettings.ts
@@ -1,31 +1,11 @@
 import { useCallback, useSyncExternalStore } from "react";
 import { Option, Schema } from "effect";
-import { type ProviderKind, type ProviderServiceTier } from "@t3tools/contracts";
+import { type ProviderKind } from "@t3tools/contracts";
 import { getDefaultModel, getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
 
 const APP_SETTINGS_STORAGE_KEY = "t3code:app-settings:v1";
 const MAX_CUSTOM_MODEL_COUNT = 32;
 export const MAX_CUSTOM_MODEL_LENGTH = 256;
-export const APP_SERVICE_TIER_OPTIONS = [
-  {
-    value: "auto",
-    label: "Automatic",
-    description: "Use Codex defaults without forcing a service tier.",
-  },
-  {
-    value: "fast",
-    label: "Fast",
-    description: "Request the fast service tier when the model supports it.",
-  },
-  {
-    value: "flex",
-    label: "Flex",
-    description: "Request the flex service tier when the model supports it.",
-  },
-] as const;
-export type AppServiceTier = (typeof APP_SERVICE_TIER_OPTIONS)[number]["value"];
-const AppServiceTierSchema = Schema.Literals(["auto", "fast", "flex"]);
-const MODELS_WITH_FAST_SUPPORT = new Set(["gpt-5.4"]);
 const BUILT_IN_MODEL_SLUGS_BY_PROVIDER: Record<ProviderKind, ReadonlySet<string>> = {
   codex: new Set(getModelOptions("codex").map((option) => option.slug)),
 };
@@ -41,7 +21,6 @@ const AppSettingsSchema = Schema.Struct({
   enableAssistantStreaming: Schema.Boolean.pipe(
     Schema.withConstructorDefault(() => Option.some(false)),
   ),
-  codexServiceTier: AppServiceTierSchema.pipe(Schema.withConstructorDefault(() => Option.some("auto"))),
   customCodexModels: Schema.Array(Schema.String).pipe(
     Schema.withConstructorDefault(() => Option.some([])),
   ),
@@ -53,22 +32,6 @@ export interface AppModelOption {
   isCustom: boolean;
 }
 
-export function resolveAppServiceTier(serviceTier: AppServiceTier): ProviderServiceTier | null {
-  return serviceTier === "auto" ? null : serviceTier;
-}
-
-export function shouldShowFastTierIcon(
-  model: string | null | undefined,
-  serviceTier: AppServiceTier,
-): boolean {
-  const normalizedModel = normalizeModelSlug(model);
-  return (
-    resolveAppServiceTier(serviceTier) === "fast" &&
-    normalizedModel !== null &&
-    MODELS_WITH_FAST_SUPPORT.has(normalizedModel)
-  );
-}
-
 const DEFAULT_APP_SETTINGS = AppSettingsSchema.makeUnsafe({});
 
 let listeners: Array<() => void> = [];
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index 51b300ba8e..4485eff6b3 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -145,7 +145,6 @@ import {
   XIcon,
   CopyIcon,
   CheckIcon,
-  ZapIcon,
 } from "lucide-react";
 import { Button } from "./ui/button";
 import { Input } from "./ui/input";
@@ -205,9 +204,6 @@ import { readNativeApi } from "~/nativeApi";
 import {
   getAppModelOptions,
   resolveAppModelSelection,
-  resolveAppServiceTier,
-  shouldShowFastTierIcon,
-  type AppServiceTier,
   useAppSettings,
 } from "../appSettings";
 import {
@@ -410,7 +406,6 @@ type ComposerCommandItem =
       model: ModelSlug;
       label: string;
       description: string;
-      showFastBadge: boolean;
     };
 
 type SendPhase = "idle" | "preparing-worktree" | "sending-turn";
@@ -521,9 +516,6 @@ const ComposerCommandMenuItem = memo(function ComposerCommandMenuItem(props: {
         </Badge>
       ) : null}
       <span className="flex min-w-0 items-center gap-1.5 truncate">
-        {props.item.type === "model" && props.item.showFastBadge ? (
-          <ZapIcon className="size-3.5 shrink-0 text-amber-500" />
-        ) : null}
         <span className="truncate">{props.item.label}</span>
       </span>
       <span className="truncate text-muted-foreground/70 text-xs">{props.item.description}</span>
@@ -785,8 +777,6 @@ export default function ChatView({ threadId }: ChatViewProps) {
       activeThread.messages.length > 0 ||
       activeThread.session !== null),
   );
-  const selectedServiceTierSetting = settings.codexServiceTier;
-  const selectedServiceTier = resolveAppServiceTier(selectedServiceTierSetting);
   const lockedProvider: ProviderKind | null = hasThreadStarted
     ? (sessionProvider ?? selectedProviderByThreadId ?? null)
     : null;
@@ -1254,10 +1244,8 @@ export default function ChatView({ threadId }: ChatViewProps) {
         model: slug,
         label: name,
         description: `${providerLabel} · ${slug}`,
-        showFastBadge:
-          provider === "codex" && shouldShowFastTierIcon(slug, selectedServiceTierSetting),
       }));
-  }, [composerTrigger, searchableModelOptions, selectedServiceTierSetting, workspaceEntries]);
+  }, [composerTrigger, searchableModelOptions, workspaceEntries]);
   const composerMenuOpen = Boolean(composerTrigger);
   const activeComposerMenuItem = useMemo(
     () =>
@@ -2664,7 +2652,6 @@ export default function ChatView({ threadId }: ChatViewProps) {
           attachments: turnAttachments,
         },
         model: selectedModel || undefined,
-        serviceTier: selectedServiceTier,
         ...(selectedModelOptionsForDispatch
           ? { modelOptions: selectedModelOptionsForDispatch }
           : {}),
@@ -3699,7 +3686,6 @@ export default function ChatView({ threadId }: ChatViewProps) {
                     model={selectedModelForPickerWithCustomFallback}
                     lockedProvider={lockedProvider}
                     modelOptionsByProvider={modelOptionsByProvider}
-                    serviceTierSetting={selectedServiceTierSetting}
                     onProviderModelChange={onProviderModelSelect}
                   />
 
@@ -5542,7 +5528,6 @@ const ProviderModelPicker = memo(function ProviderModelPicker(props: {
   model: ModelSlug;
   lockedProvider: ProviderKind | null;
   modelOptionsByProvider: Record<ProviderKind, ReadonlyArray<{ slug: string; name: string }>>;
-  serviceTierSetting: AppServiceTier;
   disabled?: boolean;
   onProviderModelChange: (provider: ProviderKind, model: ModelSlug) => void;
 }) {
@@ -5575,9 +5560,6 @@ const ProviderModelPicker = memo(function ProviderModelPicker(props: {
       >
         <span className="flex min-w-0 items-center gap-2">
           <ProviderIcon aria-hidden="true" className="size-4 shrink-0 text-muted-foreground/70" />
-          {props.provider === "codex" && shouldShowFastTierIcon(props.model, props.serviceTierSetting) ? (
-            <ZapIcon className="size-3.5 shrink-0 text-amber-500" />
-          ) : null}
           <span className="truncate">{selectedModelLabel}</span>
           <ChevronDownIcon aria-hidden="true" className="size-3 opacity-60" />
         </span>
@@ -5620,10 +5602,6 @@ const ProviderModelPicker = memo(function ProviderModelPicker(props: {
                         value={modelOption.slug}
                         onClick={() => setIsMenuOpen(false)}
                       >
-                        {option.value === "codex" &&
-                        shouldShowFastTierIcon(modelOption.slug, props.serviceTierSetting) ? (
-                          <ZapIcon className="size-3.5 shrink-0 text-amber-500" />
-                        ) : null}
                         {modelOption.name}
                       </MenuRadioItem>
                     ))}
diff --git a/apps/web/src/routes/_chat.settings.tsx b/apps/web/src/routes/_chat.settings.tsx
index cc4a39a272..8dfeb210f2 100644
--- a/apps/web/src/routes/_chat.settings.tsx
+++ b/apps/web/src/routes/_chat.settings.tsx
@@ -3,14 +3,8 @@ import { useQuery } from "@tanstack/react-query";
 import { useCallback, useState } from "react";
 import { type ProviderKind } from "@t3tools/contracts";
 import { getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
-import { ZapIcon } from "lucide-react";
-
-import {
-  APP_SERVICE_TIER_OPTIONS,
-  MAX_CUSTOM_MODEL_LENGTH,
-  shouldShowFastTierIcon,
-  useAppSettings,
-} from "../appSettings";
+
+import { MAX_CUSTOM_MODEL_LENGTH, useAppSettings } from "../appSettings";
 import { isElectron } from "../env";
 import { useTheme } from "../hooks/useTheme";
 import { serverConfigQueryOptions } from "../lib/serverReactQuery";
@@ -18,7 +12,6 @@ import { ensureNativeApi } from "../nativeApi";
 import { preferredTerminalEditor } from "../terminal-links";
 import { Button } from "../components/ui/button";
 import { Input } from "../components/ui/input";
-import { Select, SelectItem, SelectPopup, SelectTrigger, SelectValue } from "../components/ui/select";
 import { Switch } from "../components/ui/switch";
 import { SidebarInset } from "~/components/ui/sidebar";
 
@@ -103,7 +96,6 @@ function SettingsRouteView() {
 
   const codexBinaryPath = settings.codexBinaryPath;
   const codexHomePath = settings.codexHomePath;
-  const codexServiceTier = settings.codexServiceTier;
   const keybindingsConfigPath = serverConfigQuery.data?.keybindingsConfigPath ?? null;
 
   const openKeybindingsFile = useCallback(() => {
@@ -310,43 +302,6 @@ function SettingsRouteView() {
               </div>
 
               <div className="space-y-5">
-                <label className="block space-y-1">
-                  <span className="text-xs font-medium text-foreground">Default service tier</span>
-                  <Select
-                    items={APP_SERVICE_TIER_OPTIONS.map((option) => ({
-                      label: option.label,
-                      value: option.value,
-                    }))}
-                    value={codexServiceTier}
-                    onValueChange={(value) => {
-                      if (!value) return;
-                      updateSettings({ codexServiceTier: value });
-                    }}
-                  >
-                    <SelectTrigger>
-                      <SelectValue />
-                    </SelectTrigger>
-                    <SelectPopup alignItemWithTrigger={false}>
-                      {APP_SERVICE_TIER_OPTIONS.map((option) => (
-                        <SelectItem key={option.value} value={option.value}>
-                          <div className="flex min-w-0 items-center gap-2">
-                            {option.value === "fast" ? (
-                              <ZapIcon className="size-3.5 text-amber-500" />
-                            ) : (
-                              <span className="size-3.5 shrink-0" aria-hidden="true" />
-                            )}
-                            <span className="truncate">{option.label}</span>
-                          </div>
-                        </SelectItem>
-                      ))}
-                    </SelectPopup>
-                  </Select>
-                  <span className="text-xs text-muted-foreground">
-                    {APP_SERVICE_TIER_OPTIONS.find((option) => option.value === codexServiceTier)
-                      ?.description ?? "Use Codex defaults without forcing a service tier."}
-                  </span>
-                </label>
-
                 {MODEL_PROVIDER_SETTINGS.map((providerSettings) => {
                   const provider = providerSettings.provider;
                   const customModels = getCustomModelsForProvider(settings, provider);
@@ -445,14 +400,9 @@ function SettingsRouteView() {
                                   key={`${provider}:${slug}`}
                                   className="flex items-center justify-between gap-3 rounded-lg border border-border bg-background px-3 py-2"
                                 >
-                                  <div className="flex min-w-0 flex-1 items-center gap-2">
-                                    {provider === "codex" && shouldShowFastTierIcon(slug, codexServiceTier) ? (
-                                      <ZapIcon className="size-3.5 shrink-0 text-amber-500" />
-                                    ) : null}
-                                    <code className="min-w-0 flex-1 truncate text-xs text-foreground">
-                                      {slug}
-                                    </code>
-                                  </div>
+                                  <code className="min-w-0 flex-1 truncate text-xs text-foreground">
+                                    {slug}
+                                  </code>
                                   <Button
                                     size="xs"
                                     variant="ghost"
diff --git a/packages/contracts/src/orchestration.ts b/packages/contracts/src/orchestration.ts
index af496ad2a9..ecc59f0b98 100644
--- a/packages/contracts/src/orchestration.ts
+++ b/packages/contracts/src/orchestration.ts
@@ -42,8 +42,6 @@ export const ProviderSandboxMode = Schema.Literals([
   "danger-full-access",
 ]);
 export type ProviderSandboxMode = typeof ProviderSandboxMode.Type;
-export const ProviderServiceTier = Schema.Literals(["fast", "flex"]);
-export type ProviderServiceTier = typeof ProviderServiceTier.Type;
 export const DEFAULT_PROVIDER_KIND: ProviderKind = "codex";
 const CodexProviderStartOptions = Schema.Struct({
   binaryPath: Schema.optional(TrimmedNonEmptyString),
@@ -371,7 +369,6 @@ export const ThreadTurnStartCommand = Schema.Struct({
   }),
   provider: Schema.optional(ProviderKind),
   model: Schema.optional(TrimmedNonEmptyString),
-  serviceTier: Schema.optional(Schema.NullOr(ProviderServiceTier)),
   modelOptions: Schema.optional(ProviderModelOptions),
   providerOptions: Schema.optional(ProviderStartOptions),
   assistantDeliveryMode: Schema.optional(AssistantDeliveryMode),
@@ -394,7 +391,6 @@ const ClientThreadTurnStartCommand = Schema.Struct({
   }),
   provider: Schema.optional(ProviderKind),
   model: Schema.optional(TrimmedNonEmptyString),
-  serviceTier: Schema.optional(Schema.NullOr(ProviderServiceTier)),
   modelOptions: Schema.optional(ProviderModelOptions),
   providerOptions: Schema.optional(ProviderStartOptions),
   assistantDeliveryMode: Schema.optional(AssistantDeliveryMode),
@@ -675,7 +671,6 @@ export const ThreadTurnStartRequestedPayload = Schema.Struct({
   messageId: MessageId,
   provider: Schema.optional(ProviderKind),
   model: Schema.optional(TrimmedNonEmptyString),
-  serviceTier: Schema.optional(Schema.NullOr(ProviderServiceTier)),
   modelOptions: Schema.optional(ProviderModelOptions),
   providerOptions: Schema.optional(ProviderStartOptions),
   assistantDeliveryMode: Schema.optional(AssistantDeliveryMode),
diff --git a/packages/contracts/src/provider.ts b/packages/contracts/src/provider.ts
index 5e551c5579..9d2a198b6d 100644
--- a/packages/contracts/src/provider.ts
+++ b/packages/contracts/src/provider.ts
@@ -19,7 +19,6 @@ import {
   ProviderKind,
   ProviderRequestKind,
   ProviderSandboxMode,
-  ProviderServiceTier,
   ProviderUserInputAnswers,
   RuntimeMode,
 } from "./orchestration";
@@ -65,7 +64,6 @@ export const ProviderSessionStartInput = Schema.Struct({
   model: Schema.optional(TrimmedNonEmptyStringSchema),
   modelOptions: Schema.optional(ProviderModelOptions),
   resumeCursor: Schema.optional(Schema.Unknown),
-  serviceTier: Schema.optional(Schema.NullOr(ProviderServiceTier)),
   approvalPolicy: Schema.optional(ProviderApprovalPolicy),
   sandboxMode: Schema.optional(ProviderSandboxMode),
   providerOptions: Schema.optional(ProviderStartOptions),
@@ -82,7 +80,6 @@ export const ProviderSendTurnInput = Schema.Struct({
     Schema.Array(ChatAttachment).check(Schema.isMaxLength(PROVIDER_SEND_TURN_MAX_ATTACHMENTS)),
   ),
   model: Schema.optional(TrimmedNonEmptyStringSchema),
-  serviceTier: Schema.optional(Schema.NullOr(ProviderServiceTier)),
   modelOptions: Schema.optional(ProviderModelOptions),
   interactionMode: Schema.optional(ProviderInteractionMode),
 });