diff --git a/apps/web/src/components/chat/TraitsPicker.test.ts b/apps/web/src/components/chat/TraitsPicker.test.ts
index 0cb199d64ba..b457f515ff7 100644
--- a/apps/web/src/components/chat/TraitsPicker.test.ts
+++ b/apps/web/src/components/chat/TraitsPicker.test.ts
@@ -35,39 +35,48 @@ const CONTEXT_WINDOW = selectDescriptor(
 
 const CODEX = ProviderDriverKind.make("codex");
 
-function display(descriptors: ReadonlyArray<ProviderOptionDescriptor>, fastModeEnabled: boolean) {
+function display(descriptors: ReadonlyArray<ProviderOptionDescriptor>) {
   return buildTraitsTriggerDisplay({
     provider: CODEX,
     descriptors,
     primarySelectDescriptorId: "reasoningEffort",
     ultrathinkPromptControlled: false,
-    fastModeEnabled,
   });
 }
 
 describe("buildTraitsTriggerDisplay", () => {
   it("omits fast mode from the label entirely when it is off", () => {
-    expect(display([EFFORT, fastModeDescriptor(false), CONTEXT_WINDOW], false)).toEqual({
+    expect(display([EFFORT, fastModeDescriptor(false), CONTEXT_WINDOW])).toEqual({
       label: "High · 1M",
       showFastModeIcon: false,
     });
   });
 
   it("shows the bolt instead of a text label when fast mode is on", () => {
-    expect(display([EFFORT, fastModeDescriptor(true), CONTEXT_WINDOW], true)).toEqual({
+    expect(display([EFFORT, fastModeDescriptor(true), CONTEXT_WINDOW])).toEqual({
       label: "High · 1M",
       showFastModeIcon: true,
     });
   });
 
-  it("omits Codex's default Standard tier beside reasoning", () => {
+  it("renders Codex's Standard and Fast service tiers as fast mode", () => {
     const serviceTier = selectDescriptor(
       "serviceTier",
-      [{ id: "default", label: "Standard", isDefault: true }],
+      [
+        { id: "default", label: "Standard", isDefault: true },
+        { id: "priority", label: "Fast" },
+      ],
       "default",
     );
 
-    expect(display([EFFORT, serviceTier], false).label).toBe("High");
+    expect(display([EFFORT, serviceTier])).toEqual({
+      label: "High",
+      showFastModeIcon: false,
+    });
+    expect(display([EFFORT, { ...serviceTier, currentValue: "priority" }])).toEqual({
+      label: "High",
+      showFastModeIcon: true,
+    });
   });
 
   it("keeps non-fastMode booleans as text labels", () => {
@@ -77,18 +86,18 @@ describe("buildTraitsTriggerDisplay", () => {
       type: "boolean",
       currentValue: true,
     };
-    expect(display([EFFORT, thinking], false)).toEqual({
+    expect(display([EFFORT, thinking])).toEqual({
       label: "High · Thinking On",
       showFastModeIcon: false,
     });
   });
 
   it("falls back to a text label when fast mode is the only trait", () => {
-    expect(display([fastModeDescriptor(true)], true)).toEqual({
+    expect(display([fastModeDescriptor(true)])).toEqual({
       label: "Fast",
       showFastModeIcon: false,
     });
-    expect(display([fastModeDescriptor(false)], false)).toEqual({
+    expect(display([fastModeDescriptor(false)])).toEqual({
       label: "Normal",
       showFastModeIcon: false,
     });
@@ -107,7 +116,7 @@ describe("buildTraitsTriggerDisplay", () => {
         { id: "high", label: "High" },
       ],
     };
-    expect(display([unresolved], false)).toEqual({ label: "", showFastModeIcon: false });
+    expect(display([unresolved])).toEqual({ label: "", showFastModeIcon: false });
   });
 
   it("still renders the prompt-controlled ultrathink label alongside the bolt", () => {
@@ -117,7 +126,6 @@ describe("buildTraitsTriggerDisplay", () => {
         descriptors: [EFFORT, fastModeDescriptor(true)],
         primarySelectDescriptorId: "reasoningEffort",
         ultrathinkPromptControlled: true,
-        fastModeEnabled: true,
       }),
     ).toEqual({ label: "Ultrathink", showFastModeIcon: true });
   });
diff --git a/apps/web/src/components/chat/TraitsPicker.tsx b/apps/web/src/components/chat/TraitsPicker.tsx
index f95f3a4c08a..a9f910ec064 100644
--- a/apps/web/src/components/chat/TraitsPicker.tsx
+++ b/apps/web/src/components/chat/TraitsPicker.tsx
@@ -134,8 +134,6 @@ function getSelectedTraits(
       : getDescriptorStringValue(primarySelectDescriptor)) ?? null;
   const thinkingEnabled =
     typeof thinkingDescriptor?.currentValue === "boolean" ? thinkingDescriptor.currentValue : null;
-  const fastModeEnabled =
-    typeof fastModeDescriptor?.currentValue === "boolean" ? fastModeDescriptor.currentValue : false;
   const contextWindow = getDescriptorStringValue(contextWindowDescriptor);
   const selectedAgent = getDescriptorStringValue(agentDescriptor);
   const selectedAgentLabel = agentDescriptor
@@ -154,7 +152,6 @@ function getSelectedTraits(
     thinkingDescriptor,
     effort,
     thinkingEnabled,
-    fastModeEnabled,
     contextWindow,
     ultrathinkPromptControlled,
     ultrathinkInBodyText,
@@ -392,24 +389,26 @@ export function buildTraitsTriggerDisplay(input: {
   descriptors: ReadonlyArray<ProviderOptionDescriptor>;
   primarySelectDescriptorId: string | null;
   ultrathinkPromptControlled: boolean;
-  fastModeEnabled: boolean;
 }): { label: string; showFastModeIcon: boolean } {
   let hasFastMode = false;
+  let fastModeEnabled = false;
   const labels: Array<string> = [];
   for (const descriptor of input.descriptors) {
     if (descriptor.id === "fastMode" && descriptor.type === "boolean") {
       hasFastMode = true;
+      fastModeEnabled = descriptor.currentValue === true;
       continue;
     }
     if (
       input.provider === "codex" &&
       descriptor.id === "serviceTier" &&
-      descriptor.type === "select" &&
-      input.descriptors.some(({ id }) => id === "reasoningEffort")
+      descriptor.type === "select"
     ) {
       const currentValue = getProviderOptionCurrentValue(descriptor);
-      const currentOption = descriptor.options.find((option) => option.id === currentValue);
-      if (currentOption?.id === "default" && currentOption.isDefault === true) {
+      const fastTier = descriptor.options.find(({ label }) => label === "Fast");
+      if (fastTier && (currentValue === "default" || currentValue === fastTier.id)) {
+        hasFastMode = true;
+        fastModeEnabled = currentValue === fastTier.id;
         continue;
       }
     }
@@ -428,9 +427,9 @@ export function buildTraitsTriggerDisplay(input: {
   // off an empty label list alone would also catch descriptors that resolved to
   // no label at all, printing a bogus "Normal" for a model without fast mode.
   if (labels.length === 0 && hasFastMode) {
-    return { label: input.fastModeEnabled ? "Fast" : "Normal", showFastModeIcon: false };
+    return { label: fastModeEnabled ? "Fast" : "Normal", showFastModeIcon: false };
   }
-  return { label: labels.join(" · "), showFastModeIcon: input.fastModeEnabled };
+  return { label: labels.join(" · "), showFastModeIcon: fastModeEnabled };
 }
 
 export const TraitsPicker = memo(function TraitsPicker({
@@ -447,7 +446,7 @@ export const TraitsPicker = memo(function TraitsPicker({
   ...persistence
 }: TraitsMenuContentProps & TraitsPersistence) {
   const [isMenuOpen, setIsMenuOpen] = useState(false);
-  const { descriptors, primarySelectDescriptor, ultrathinkPromptControlled, fastModeEnabled } =
+  const { descriptors, primarySelectDescriptor, ultrathinkPromptControlled } =
     getTraitsSectionVisibility({
       provider,
       models,
@@ -474,7 +473,6 @@ export const TraitsPicker = memo(function TraitsPicker({
     descriptors,
     primarySelectDescriptorId: primarySelectDescriptor?.id ?? null,
     ultrathinkPromptControlled,
-    fastModeEnabled,
   });
   const fastModeIcon = showFastModeIcon ? (
     <>