fix(codex): show catalog-default Fast tier (#1179)

* fix(codex): show catalog-default Fast tier

* fix(web): show inherited Fast tier in header

cli/src/modules/common/codexModels.ts

@@ -74,6 +74,7 @@ function normalizeModel(entry: unknown): CodexModelSummary | null {
         displayName: asNonEmptyString(record.displayName) ?? id,
         isDefault: record.isDefault === true,
         defaultReasoningEffort: asNonEmptyString(record.defaultReasoningEffort),
+        defaultServiceTier: asNonEmptyString(record.defaultServiceTier),
         supportedReasoningEfforts: normalizeSupportedReasoningEfforts(record.supportedReasoningEfforts),
         serviceTiers: normalizeServiceTiers(record.serviceTiers)
     };

shared/src/apiTypes.ts

@@ -433,6 +433,7 @@ export type CodexModelSummary = {
     displayName: string
     isDefault: boolean
     defaultReasoningEffort?: string | null
+    defaultServiceTier?: string | null
     supportedReasoningEfforts?: string[]
     /** Service tier ids advertised for this model in the current auth/plan context (e.g. 'fast'). */
     serviceTiers?: string[]

web/src/components/AssistantChat/codexFastMode.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import {
     codexModelAdvertisesFastTier,
+    getEffectiveCodexServiceTier,
     getDisplayedCodexServiceTier,
     isFastServiceTier
 } from './codexFastMode'
@@ -45,6 +46,7 @@ describe('isFastServiceTier', () => {
     it('detects the fast tier regardless of casing/spacing', () => {
         expect(isFastServiceTier('fast')).toBe(true)
         expect(isFastServiceTier(' Fast ')).toBe(true)
+        expect(isFastServiceTier('priority')).toBe(true)
     })
 
     it('treats null/standard as not fast', () => {
@@ -54,6 +56,17 @@ describe('isFastServiceTier', () => {
     })
 })
 
+describe('getEffectiveCodexServiceTier', () => {
+    it('uses the active model default only when the session has no override', () => {
+        const modelsWithDefault = models.map((model) => (
+            model.id === 'gpt-5.5' ? { ...model, defaultServiceTier: 'priority' } : model
+        ))
+
+        expect(getEffectiveCodexServiceTier(null, null, modelsWithDefault)).toBe('priority')
+        expect(getEffectiveCodexServiceTier('standard', null, modelsWithDefault)).toBe('standard')
+    })
+})
+
 describe('getDisplayedCodexServiceTier', () => {
     it('displays untouched and explicit non-fast tiers as standard', () => {
         expect(getDisplayedCodexServiceTier(null)).toBe('standard')

web/src/components/AssistantChat/codexFastMode.ts

@@ -8,6 +8,7 @@
 type CodexModelCatalogEntry = {
     id: string
     isDefault: boolean
+    defaultServiceTier?: string | null
     serviceTiers?: string[]
 }
 
@@ -47,7 +48,15 @@ export function codexModelAdvertisesFastTier(
 }
 
 export function isFastServiceTier(serviceTier?: string | null): boolean {
-    return serviceTier?.trim().toLowerCase() === 'fast'
+    return /^(fast|priority)$/i.test(serviceTier?.trim() ?? '')
+}
+
+export function getEffectiveCodexServiceTier(
+    serviceTier: string | null | undefined,
+    sessionModel: string | null | undefined,
+    models: ReadonlyArray<CodexModelCatalogEntry>
+): string | null | undefined {
+    return serviceTier ?? findActiveModel(sessionModel, models)?.defaultServiceTier
 }
 
 /**

web/src/components/SessionChat.tsx

@@ -26,7 +26,7 @@ import {
     supportsCodexReasoningEffort
 } from '@/lib/codexModelCapabilities'
 import { HappyComposer, type ComposerSendError } from '@/components/AssistantChat/HappyComposer'
-import { codexModelAdvertisesFastTier } from '@/components/AssistantChat/codexFastMode'
+import { codexModelAdvertisesFastTier, getEffectiveCodexServiceTier } from '@/components/AssistantChat/codexFastMode'
 import type { PendingSchedule } from '@/components/AssistantChat/ScheduleTimePicker'
 import { resolvePendingSchedule } from '@/components/AssistantChat/ScheduleTimePicker'
 import { HappyThread } from '@/components/AssistantChat/HappyThread'
@@ -543,6 +543,13 @@ function SessionChatInner(props: SessionChatProps) {
         sessionId: props.session.id,
         enabled: agentFlavor === 'codex' && props.session.active && !controlledByUser
     })
+    const effectiveCodexServiceTier = agentFlavor === 'codex'
+        ? getEffectiveCodexServiceTier(
+            props.session.serviceTier,
+            props.session.model,
+            codexModelsState.models
+        )
+        : undefined
     const codexModelOptions = useMemo(() => {
         if (agentFlavor !== 'codex') {
             return undefined
@@ -1199,6 +1206,7 @@ function SessionChatInner(props: SessionChatProps) {
         <div className="flex h-full min-h-0 flex-col">
             <SessionHeader
                 session={props.session}
+                serviceTier={effectiveCodexServiceTier}
                 onBack={props.onBack}
                 onToggleFiles={props.session.metadata?.path ? handleToggleFiles : undefined}
                 filesActive={false}
@@ -1431,7 +1439,7 @@ function SessionChatInner(props: SessionChatProps) {
                                     : undefined)
                                 : handleEffortChange
                         }
-                        serviceTier={agentFlavor === 'codex' ? props.session.serviceTier : undefined}
+                        serviceTier={effectiveCodexServiceTier}
                         onServiceTierChange={
                             agentFlavor === 'codex'
                                 && props.session.active

web/src/components/SessionHeader.test.tsx

@@ -0,0 +1,50 @@
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { cleanup, render, screen } from '@testing-library/react'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import type { Session } from '@/types/api'
+import { I18nProvider } from '@/lib/i18n-context'
+import { ToastProvider } from '@/lib/toast-context'
+import { SessionHeader } from './SessionHeader'
+
+afterEach(() => cleanup())
+
+describe('SessionHeader', () => {
+    it('shows an inherited catalog-default Fast tier', () => {
+        const session: Session = {
+            id: 'session-1',
+            namespace: 'default',
+            seq: 0,
+            createdAt: 0,
+            updatedAt: 0,
+            active: true,
+            activeAt: 0,
+            metadata: { flavor: 'codex', path: '/repo', host: 'machine' },
+            metadataVersion: 0,
+            agentState: null,
+            agentStateVersion: 0,
+            thinking: false,
+            thinkingAt: 0,
+            model: null,
+            modelReasoningEffort: null,
+            effort: null,
+            serviceTier: null
+        }
+
+        render(
+            <QueryClientProvider client={new QueryClient()}>
+                <ToastProvider>
+                    <I18nProvider>
+                        <SessionHeader
+                            session={session}
+                            serviceTier="priority"
+                            onBack={vi.fn()}
+                            api={null}
+                        />
+                    </I18nProvider>
+                </ToastProvider>
+            </QueryClientProvider>
+        )
+
+        expect(screen.getByText('fast')).toBeInTheDocument()
+    })
+})

web/src/components/SessionHeader.tsx

@@ -90,6 +90,7 @@ function MoreVerticalIcon(props: { className?: string }) {
 
 export function SessionHeader(props: {
     session: Session
+    serviceTier?: string | null
     onBack: () => void
     onToggleFiles?: () => void
     filesActive?: boolean
@@ -113,7 +114,7 @@ export function SessionHeader(props: {
         ? formatCodexReasoningLabel(session.modelReasoningEffort)
         : null
     // Match expected Fast badge semantics (#1004): only explicit service tier, no effort/model heuristics.
-    const showFastBadge = agentFlavor === 'codex' && isFastServiceTier(session.serviceTier)
+    const showFastBadge = agentFlavor === 'codex' && isFastServiceTier(props.serviceTier ?? session.serviceTier)
     const codexSessionId = session.metadata?.flavor === 'codex'
         ? session.metadata.codexSessionId?.trim() || null
         : null