diff --git a/desktop/src/components/controls/ModelSelector.test.tsx b/desktop/src/components/controls/ModelSelector.test.tsx
index 966fad8f..bb9760f4 100644
--- a/desktop/src/components/controls/ModelSelector.test.tsx
+++ b/desktop/src/components/controls/ModelSelector.test.tsx
@@ -1240,8 +1240,8 @@ describe('ModelSelector', () => {
 
   it('replaces a stale Grok runtime model with the current official default', async () => {
     const grokModels: ModelInfo[] = [{
-      id: 'grok-4.6',
-      name: 'Grok 4.6',
+      id: 'grok-4.7',
+      name: 'Grok 4.7',
       description: "SpaceXAI's latest frontier model",
       context: '500000',
       defaultReasoningEffort: 'high',
@@ -1272,11 +1272,11 @@ describe('ModelSelector', () => {
     render(<ModelSelector runtimeKey="session-stale-grok" />)
 
     expect(screen.queryByText('grok-build')).not.toBeInTheDocument()
-    expect(screen.getByRole('button', { name: 'Grok 4.6, Grok Official' })).toBeInTheDocument()
+    expect(screen.getByRole('button', { name: 'Grok 4.7, Grok Official' })).toBeInTheDocument()
     await waitFor(() => {
       expect(useSessionRuntimeStore.getState().selections['session-stale-grok']).toEqual({
         providerId: 'grok-official',
-        modelId: 'grok-4.6',
+        modelId: 'grok-4.7',
         effortLevel: 'high',
       })
     })
diff --git a/desktop/src/constants/grokOfficialProvider.ts b/desktop/src/constants/grokOfficialProvider.ts
index 3ca4979c..3c58eb89 100644
--- a/desktop/src/constants/grokOfficialProvider.ts
+++ b/desktop/src/constants/grokOfficialProvider.ts
@@ -1,18 +1,34 @@
 import type { ModelInfo } from '../types/settings'
 
 export const GROK_OFFICIAL_PROVIDER_ID = 'grok-official'
-export const GROK_OFFICIAL_DEFAULT_MODEL_ID = 'grok-4.6'
+export const GROK_OFFICIAL_DEFAULT_MODEL_ID = 'grok-4.7'
 export const GROK_OFFICIAL_PROVIDER_NAME = 'Grok Official'
 
 export const GROK_OFFICIAL_MODELS: ModelInfo[] = [
   {
     id: GROK_OFFICIAL_DEFAULT_MODEL_ID,
-    name: 'Grok 4.6',
+    name: 'Grok 4.7',
     description: "SpaceXAI's latest frontier model",
     context: '500000',
     defaultReasoningEffort: 'high',
     supportedReasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
   },
+  {
+    id: 'grok-4.7-build-fast',
+    name: 'Grok 4.7 Fast',
+    description: 'Fast variant. 2x the price.',
+    context: '500000',
+    defaultReasoningEffort: 'high',
+    supportedReasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
+  },
+  {
+    id: 'grok-4.6',
+    name: 'Grok 4.6',
+    description: 'Grok 4.6 frontier model',
+    context: '500000',
+    defaultReasoningEffort: 'high',
+    supportedReasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
+  },
   {
     id: 'grok-4.5',
     name: 'Grok 4.5',
@@ -21,11 +37,4 @@ export const GROK_OFFICIAL_MODELS: ModelInfo[] = [
     defaultReasoningEffort: 'high',
     supportedReasoningEfforts: ['low', 'medium', 'high'],
   },
-  {
-    id: 'grok-composer-2.5-fast',
-    name: 'Composer 2.5',
-    description: 'Grok coding model',
-    context: '200000',
-    supportedReasoningEfforts: [],
-  },
 ]
diff --git a/desktop/src/lib/runtimeSelection.test.ts b/desktop/src/lib/runtimeSelection.test.ts
index f5226266..d1f4cdd9 100644
--- a/desktop/src/lib/runtimeSelection.test.ts
+++ b/desktop/src/lib/runtimeSelection.test.ts
@@ -104,18 +104,16 @@ describe('normalizeRuntimeSelection', () => {
     })
   })
 
-  it('removes effort from a non-reasoning Grok model', () => {
+  it('keeps xhigh for Grok models that support it', () => {
     expect(normalizeRuntimeSelection({
       providerId: 'grok-official',
-      modelId: 'grok-composer-2.5-fast',
+      modelId: 'grok-4.7',
       effortLevel: 'xhigh',
     })).toEqual({
       providerId: 'grok-official',
-      modelId: 'grok-composer-2.5-fast',
+      modelId: 'grok-4.7',
+      effortLevel: 'xhigh',
     })
-  })
-
-  it('keeps xhigh for grok-4.6 which supports it', () => {
     expect(normalizeRuntimeSelection({
       providerId: 'grok-official',
       modelId: 'grok-4.6',
diff --git a/desktop/src/stores/providerStore.test.ts b/desktop/src/stores/providerStore.test.ts
index 2e4ace1c..151feb15 100644
--- a/desktop/src/stores/providerStore.test.ts
+++ b/desktop/src/stores/providerStore.test.ts
@@ -231,7 +231,7 @@ describe('providerStore runtime refresh', () => {
     const { useProviderStore } = await import('./providerStore')
     await useProviderStore.getState().activateProvider('grok-official')
 
-    expect(settingsSetModelMock).toHaveBeenCalledWith('grok-4.6')
+    expect(settingsSetModelMock).toHaveBeenCalledWith('grok-4.7')
     expect(settingsFetchAllMock).toHaveBeenCalled()
   })
 
diff --git a/desktop/src/stores/sessionRuntimeStore.test.ts b/desktop/src/stores/sessionRuntimeStore.test.ts
index 84b42d84..8f022b00 100644
--- a/desktop/src/stores/sessionRuntimeStore.test.ts
+++ b/desktop/src/stores/sessionRuntimeStore.test.ts
@@ -4,7 +4,7 @@ import { useSessionRuntimeStore } from './sessionRuntimeStore'
 
 const EXPECTED_GROK_SELECTION = {
   providerId: 'grok-official',
-  modelId: 'grok-4.6',
+  modelId: 'grok-4.7',
   effortLevel: 'high',
 }
 
@@ -61,20 +61,23 @@ describe('sessionRuntimeStore runtime cleanup', () => {
     expect(useSessionRuntimeStore.getState().selections[metadata.id]).toEqual({ providerId: 'kimi', modelId: 'k3' })
   })
 
-  it('discards retired Grok selections before persisting them', () => {
-    useSessionRuntimeStore.getState().setSelection('session-grok', {
-      providerId: 'grok-official',
-      modelId: 'grok-build',
-      effortLevel: 'max',
-    })
+  it.each(['grok-build', 'grok-composer-2.5-fast'])(
+    'discards the retired Grok model %s before persisting it',
+    (retiredModelId) => {
+      useSessionRuntimeStore.getState().setSelection('session-grok', {
+        providerId: 'grok-official',
+        modelId: retiredModelId,
+        effortLevel: 'max',
+      })
 
-    expect(useSessionRuntimeStore.getState().selections['session-grok']).toEqual(
-      EXPECTED_GROK_SELECTION,
-    )
-    expect(JSON.parse(localStorage.getItem('cc-haha-session-runtime')!)).toEqual({
-      'session-grok': EXPECTED_GROK_SELECTION,
-    })
-  })
+      expect(useSessionRuntimeStore.getState().selections['session-grok']).toEqual(
+        EXPECTED_GROK_SELECTION,
+      )
+      expect(JSON.parse(localStorage.getItem('cc-haha-session-runtime')!)).toEqual({
+        'session-grok': EXPECTED_GROK_SELECTION,
+      })
+    },
+  )
 
   it('does not let retired Grok session metadata restore the removed model', () => {
     useSessionRuntimeStore.getState().syncFromSessions([{
diff --git a/desktop/src/stores/sessionRuntimeStore.ts b/desktop/src/stores/sessionRuntimeStore.ts
index 416540f7..330f896a 100644
--- a/desktop/src/stores/sessionRuntimeStore.ts
+++ b/desktop/src/stores/sessionRuntimeStore.ts
@@ -20,6 +20,9 @@ const RETIRED_GROK_MODEL_IDS = new Set([
   'grok-4.3',
   'grok-4.20-reasoning',
   'grok-4.20-non-reasoning',
+  // Dropped from the live /v1/models feed, so a session still pinned to it
+  // would send an ID the gateway no longer serves.
+  'grok-composer-2.5-fast',
 ])
 
 export const DRAFT_RUNTIME_SELECTION_KEY = '__draft__'
diff --git a/src/server/__tests__/provider-runtime-env.test.ts b/src/server/__tests__/provider-runtime-env.test.ts
index f7b22e18..9f48c1c5 100644
--- a/src/server/__tests__/provider-runtime-env.test.ts
+++ b/src/server/__tests__/provider-runtime-env.test.ts
@@ -95,10 +95,10 @@ describe('providerRuntimeEnv', () => {
       CC_HAHA_IMAGE_PROVIDER_KIND: 'grok_oauth',
       CC_HAHA_IMAGE_PROVIDER_ID: 'grok-official',
       CC_HAHA_IMAGE_MODEL: 'grok-imagine-image-quality',
-      ANTHROPIC_MODEL: 'grok-4.6',
-      ANTHROPIC_DEFAULT_HAIKU_MODEL: 'grok-4.6',
-      ANTHROPIC_DEFAULT_SONNET_MODEL: 'grok-4.6',
-      ANTHROPIC_DEFAULT_OPUS_MODEL: 'grok-4.6',
+      ANTHROPIC_MODEL: 'grok-4.7',
+      ANTHROPIC_DEFAULT_HAIKU_MODEL: 'grok-4.7',
+      ANTHROPIC_DEFAULT_SONNET_MODEL: 'grok-4.7',
+      ANTHROPIC_DEFAULT_OPUS_MODEL: 'grok-4.7',
       DISABLE_AUTOUPDATER: '1',
     })
     expect(env.CC_HAHA_OPENAI_OAUTH_PROVIDER).toBeUndefined()
diff --git a/src/server/__tests__/providers.test.ts b/src/server/__tests__/providers.test.ts
index 21e1de70..d56451fd 100644
--- a/src/server/__tests__/providers.test.ts
+++ b/src/server/__tests__/providers.test.ts
@@ -732,10 +732,10 @@ describe('ProviderService', () => {
           apiFormat: 'openai_chat',
           runtimeKind: 'grok_oauth',
           models: {
-            main: 'grok-4.6',
-            haiku: 'grok-4.6',
-            sonnet: 'grok-4.6',
-            opus: 'grok-4.6',
+            main: 'grok-4.7',
+            haiku: 'grok-4.7',
+            sonnet: 'grok-4.7',
+            opus: 'grok-4.7',
           },
         })
 
@@ -749,10 +749,10 @@ describe('ProviderService', () => {
         expect(env.GROK_OAUTH_FILE).toBe(
           path.join(tmpDir, 'cc-haha', 'grok-oauth.json'),
         )
-        expect(env.ANTHROPIC_MODEL).toBe('grok-4.6')
-        expect(env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('grok-4.6')
-        expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('grok-4.6')
-        expect(env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('grok-4.6')
+        expect(env.ANTHROPIC_MODEL).toBe('grok-4.7')
+        expect(env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('grok-4.7')
+        expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('grok-4.7')
+        expect(env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('grok-4.7')
         expect(env.CC_HAHA_OPENAI_OAUTH_PROVIDER).toBeUndefined()
         expect(env.OPENAI_CODEX_OAUTH_FILE).toBeUndefined()
       })
diff --git a/src/server/__tests__/settings.test.ts b/src/server/__tests__/settings.test.ts
index d73942fd..639c6457 100644
--- a/src/server/__tests__/settings.test.ts
+++ b/src/server/__tests__/settings.test.ts
@@ -1485,10 +1485,13 @@ describe('Models API', () => {
     }
     expect(body.provider).toEqual({ id: 'grok-official', name: 'Grok Official' })
     expect(body.models.map((model) => model.id)).toEqual([
+      'grok-4.7',
+      'grok-4.7-build-fast',
       'grok-4.6',
       'grok-4.5',
-      'grok-composer-2.5-fast',
     ])
+    expect(body.models.find((model) => model.id === 'grok-4.7')?.context).toBe('500000')
+    expect(body.models.find((model) => model.id === 'grok-4.7-build-fast')?.context).toBe('500000')
     expect(body.models.find((model) => model.id === 'grok-4.6')?.context).toBe('500000')
     expect(body.models.find((model) => model.id === 'grok-4.5')?.context).toBe('500000')
   })
diff --git a/src/server/services/grokOfficialProvider.test.ts b/src/server/services/grokOfficialProvider.test.ts
index b3015de4..a7d206ef 100644
--- a/src/server/services/grokOfficialProvider.test.ts
+++ b/src/server/services/grokOfficialProvider.test.ts
@@ -30,6 +30,8 @@ describe('Grok Official runtime environment', () => {
 
     expect(windows['grok-next-preview']).toBe(375_000)
     expect(windows['grok-window-unknown']).toBeUndefined()
+    expect(windows['grok-4.7']).toBe(500_000)
+    expect(windows['grok-4.7-build-fast']).toBe(500_000)
     expect(windows['grok-4.6']).toBe(500_000)
     expect(windows['grok-4.5']).toBe(500_000)
   })
diff --git a/src/server/services/grokOfficialProvider.ts b/src/server/services/grokOfficialProvider.ts
index 79c9b7b4..da1d79c6 100644
--- a/src/server/services/grokOfficialProvider.ts
+++ b/src/server/services/grokOfficialProvider.ts
@@ -4,8 +4,8 @@ import {
   GROK_DEFAULT_SONNET_MODEL,
   GROK_MODEL_CATALOG,
   getGrokContextWindowForModel,
+  getGrokRuntimeModelCatalog,
 } from '../../services/grokAuth/models.js'
-import { getGrokRuntimeModelCatalog } from '../../services/grokAuth/modelCatalog.js'
 import { GROK_OAUTH_FILE_ENV_KEY } from '../../services/grokAuth/storage.js'
 import { MODEL_CONTEXT_WINDOWS_ENV_KEY } from '../../utils/model/modelContextWindows.js'
 import {
diff --git a/src/services/grokAuth/fetch.test.ts b/src/services/grokAuth/fetch.test.ts
index d0fec191..87fa6e9d 100644
--- a/src/services/grokAuth/fetch.test.ts
+++ b/src/services/grokAuth/fetch.test.ts
@@ -9,6 +9,11 @@ import {
 } from './fetch.js'
 import { GROK_OAUTH_FILE_ENV_KEY } from './storage.js'
 import { GROK_OAUTH_TOKEN_ENDPOINT } from './client.js'
+import {
+  GROK_MODEL_CATALOG,
+  setGrokRuntimeModelCatalog,
+  type GrokModelCatalogEntry,
+} from './models.js'
 import { isRetryableStreamTransportError } from '../api/withRetry.js'
 
 describe('Grok Responses fetch adapter', () => {
@@ -27,6 +32,7 @@ describe('Grok Responses fetch adapter', () => {
   })
 
   afterEach(async () => {
+    setGrokRuntimeModelCatalog(GROK_MODEL_CATALOG)
     if (original === undefined) delete process.env[GROK_OAUTH_FILE_ENV_KEY]
     else process.env[GROK_OAUTH_FILE_ENV_KEY] = original
     await fs.rm(tmpDir, { recursive: true, force: true })
@@ -81,12 +87,15 @@ describe('Grok Responses fetch adapter', () => {
   })
 
   test('drops Claude reasoning effort for Grok models that reject it', async () => {
+    setGrokRuntimeModelCatalog([
+      liveModel('grok-4.8', { supportsReasoningEffort: false }),
+    ])
     let upstreamBody: Record<string, unknown> | undefined
     const fetchOverride: typeof fetch = async (_input, init) => {
       upstreamBody = JSON.parse(String(init?.body))
       return new Response([
         'event: response.completed',
-        'data: {"response":{"id":"resp_no_effort","object":"response","created_at":1,"model":"grok-composer-2.5-fast","status":"completed","output":[],"usage":{"input_tokens":1,"output_tokens":1,"total_tokens":2}}}',
+        'data: {"response":{"id":"resp_no_effort","object":"response","created_at":1,"model":"grok-4.8","status":"completed","output":[],"usage":{"input_tokens":1,"output_tokens":1,"total_tokens":2}}}',
         '',
       ].join('\n'), { headers: { 'Content-Type': 'text/event-stream' } })
     }
@@ -94,7 +103,7 @@ describe('Grok Responses fetch adapter', () => {
     const response = await buildGrokFetch(fetchOverride, 'test')(
       'https://api.anthropic.com/v1/messages',
       { method: 'POST', body: JSON.stringify({
-        model: 'grok-composer-2.5-fast',
+        model: 'grok-4.8',
         max_tokens: 64,
         output_config: { effort: 'max' },
         messages: [{ role: 'user', content: 'hello' }],
@@ -105,6 +114,72 @@ describe('Grok Responses fetch adapter', () => {
     expect(upstreamBody?.reasoning).toBeUndefined()
   })
 
+  test('honors the effort set the live catalog declares for a model this build predates', async () => {
+    // Regression: `resolveGrokReasoningEffort` used to read only the bundled
+    // catalog, so the live feed's per-model capability declaration was ignored
+    // for every model newer than this build.
+    setGrokRuntimeModelCatalog([
+      liveModel('grok-4.8', {
+        supportsReasoningEffort: true,
+        reasoningEffort: 'high',
+        reasoningEfforts: ['high', 'medium', 'low'],
+      }),
+    ])
+    let upstreamBody: Record<string, unknown> | undefined
+    const fetchOverride: typeof fetch = async (_input, init) => {
+      upstreamBody = JSON.parse(String(init?.body))
+      return new Response([
+        'event: response.completed',
+        'data: {"response":{"id":"resp_live_effort","object":"response","created_at":1,"model":"grok-4.8","status":"completed","output":[],"usage":{"input_tokens":1,"output_tokens":1,"total_tokens":2}}}',
+        '',
+      ].join('\n'), { headers: { 'Content-Type': 'text/event-stream' } })
+    }
+
+    const response = await buildGrokFetch(fetchOverride, 'test')(
+      'https://api.anthropic.com/v1/messages',
+      { method: 'POST', body: JSON.stringify({
+        model: 'grok-4.8',
+        max_tokens: 64,
+        output_config: { effort: 'xhigh' },
+        messages: [{ role: 'user', content: 'hello' }],
+      }) },
+    )
+
+    expect(response.status).toBe(200)
+    // xhigh is not in the live set, so it must clamp to the declared default
+    // rather than being forwarded or dropped.
+    expect(upstreamBody?.reasoning).toEqual({ effort: 'high' })
+  })
+
+  test('forwards the selected effort for a model neither catalog describes', async () => {
+    // The old fallback returned undefined here, and the transform reads that as
+    // "the model rejects effort" and deletes the whole reasoning block — so a
+    // model launched after this build ran at the upstream default no matter what
+    // the user selected.
+    let upstreamBody: Record<string, unknown> | undefined
+    const fetchOverride: typeof fetch = async (_input, init) => {
+      upstreamBody = JSON.parse(String(init?.body))
+      return new Response([
+        'event: response.completed',
+        'data: {"response":{"id":"resp_unknown_effort","object":"response","created_at":1,"model":"grok-4.9-preview","status":"completed","output":[],"usage":{"input_tokens":1,"output_tokens":1,"total_tokens":2}}}',
+        '',
+      ].join('\n'), { headers: { 'Content-Type': 'text/event-stream' } })
+    }
+
+    const response = await buildGrokFetch(fetchOverride, 'test')(
+      'https://api.anthropic.com/v1/messages',
+      { method: 'POST', body: JSON.stringify({
+        model: 'grok-4.9-preview',
+        max_tokens: 64,
+        output_config: { effort: 'xhigh' },
+        messages: [{ role: 'user', content: 'hello' }],
+      }) },
+    )
+
+    expect(response.status).toBe(200)
+    expect(upstreamBody?.reasoning).toEqual({ effort: 'xhigh' })
+  })
+
   test('routes remotely discovered model IDs without silently replacing them', async () => {
     let upstreamBody: Record<string, unknown> | undefined
     let upstreamHeaders: Headers | undefined
@@ -377,3 +452,17 @@ describe('Grok Responses fetch adapter', () => {
     expect(calls).toBe(1)
   })
 })
+
+/** A `/v1/models` row as the CLI proxy advertises it. */
+function liveModel(
+  value: string,
+  overrides: Partial<GrokModelCatalogEntry>,
+): GrokModelCatalogEntry {
+  return {
+    value,
+    label: value,
+    description: '',
+    contextWindow: 500_000,
+    ...overrides,
+  }
+}
diff --git a/src/services/grokAuth/fetch.ts b/src/services/grokAuth/fetch.ts
index 2248fe9b..224ce4a2 100644
--- a/src/services/grokAuth/fetch.ts
+++ b/src/services/grokAuth/fetch.ts
@@ -4,7 +4,11 @@ import { openaiResponsesStreamToAnthropic } from '../../server/proxy/streaming/o
 import { openaiResponsesStreamToAnthropicResponse } from '../../server/proxy/streaming/openaiResponsesStreamToAnthropicResponse.js'
 import type { AnthropicRequest } from '../../server/proxy/transform/types.js'
 import { ensureFreshGrokTokens, forceRefreshGrokTokens } from './refresh.js'
-import { resolveGrokModel, resolveGrokReasoningEffort } from './models.js'
+import {
+  getGrokRuntimeModelCatalog,
+  resolveGrokModel,
+  resolveGrokReasoningEffort,
+} from './models.js'
 import { getGrokOAuthTokens } from './storage.js'
 
 export const GROK_CLI_BASE_URL = 'https://cli-chat-proxy.grok.com/v1'
@@ -55,6 +59,7 @@ export function buildGrokFetch(
     const reasoningEffort = resolveGrokReasoningEffort(
       requestedModel,
       transformedBody.reasoning?.effort,
+      getGrokRuntimeModelCatalog(),
     )
     if (reasoningEffort) {
       transformedBody.reasoning = {
diff --git a/src/services/grokAuth/modelCatalog.test.ts b/src/services/grokAuth/modelCatalog.test.ts
index 64832848..442c1c02 100644
--- a/src/services/grokAuth/modelCatalog.test.ts
+++ b/src/services/grokAuth/modelCatalog.test.ts
@@ -79,7 +79,7 @@ describe('Grok model catalog', () => {
       forceRefresh: true,
       fetchOverride: async () => new Response('nope', { status: 503 }),
     })
-    expect(models[0]?.value).toBe('grok-4.6')
+    expect(models[0]?.value).toBe('grok-4.7')
     expect(models.some((model) => model.value === 'grok-4.5')).toBe(true)
   })
 
diff --git a/src/services/grokAuth/modelCatalog.ts b/src/services/grokAuth/modelCatalog.ts
index aa1fcf5e..1cabc2d6 100644
--- a/src/services/grokAuth/modelCatalog.ts
+++ b/src/services/grokAuth/modelCatalog.ts
@@ -6,6 +6,7 @@ import { createModelCatalogCache } from '../modelCatalogCache.js'
 import { ensureFreshGrokTokens } from './refresh.js'
 import {
   GROK_MODEL_CATALOG,
+  setGrokRuntimeModelCatalog,
   type GrokModelCatalogEntry,
 } from './models.js'
 
@@ -16,7 +17,6 @@ const catalogCache = createModelCatalogCache<GrokModelCatalogEntry[]>({
   ttlMs: MODEL_CATALOG_TTL_MS,
   failureBackoffMs: MODEL_CATALOG_FAILURE_BACKOFF_MS,
 })
-let runtimeCatalog: readonly GrokModelCatalogEntry[] = GROK_MODEL_CATALOG
 
 export async function fetchGrokModelCatalog(
   fetchOverride: typeof fetch = globalThis.fetch,
@@ -38,7 +38,7 @@ export async function fetchGrokModelCatalog(
     .map(normalizeRemoteModel)
     .filter((model): model is GrokModelCatalogEntry => model !== null)
   if (!models.length) throw new Error('Grok models endpoint returned no models')
-  runtimeCatalog = models
+  setGrokRuntimeModelCatalog(models)
   return models
 }
 
@@ -55,17 +55,13 @@ export async function getGrokModelCatalog(options?: {
     fallback: GROK_MODEL_CATALOG,
     ...(options?.forceRefresh ? { forceRefresh: true } : {}),
   })
-  runtimeCatalog = models
+  setGrokRuntimeModelCatalog(models)
   return models
 }
 
-export function getGrokRuntimeModelCatalog(): readonly GrokModelCatalogEntry[] {
-  return runtimeCatalog
-}
-
 export function clearGrokModelCatalogCache(): void {
   catalogCache.clear()
-  runtimeCatalog = GROK_MODEL_CATALOG
+  setGrokRuntimeModelCatalog(GROK_MODEL_CATALOG)
 }
 
 function extractModelRows(body: unknown): unknown[] {
diff --git a/src/services/grokAuth/models.test.ts b/src/services/grokAuth/models.test.ts
index d57df462..93367b59 100644
--- a/src/services/grokAuth/models.test.ts
+++ b/src/services/grokAuth/models.test.ts
@@ -1,38 +1,83 @@
-import { describe, expect, test } from 'bun:test'
+import { afterEach, describe, expect, test } from 'bun:test'
 import {
   GROK_DEFAULT_MAIN_MODEL,
   GROK_MODEL_CATALOG,
   getGrokContextWindowForModel,
+  getGrokRuntimeModelCatalog,
   resolveGrokModel,
   resolveGrokReasoningEffort,
+  setGrokRuntimeModelCatalog,
 } from './models.js'
 
 describe('Grok model catalog', () => {
-  test('keeps CLI-only aliases out of the picker fallback and defaults to Grok 4.6', () => {
+  afterEach(() => setGrokRuntimeModelCatalog(GROK_MODEL_CATALOG))
+
+  test('mirrors the live picker fallback and defaults to Grok 4.7', () => {
     expect(GROK_MODEL_CATALOG.map((model) => model.value)).toEqual([
+      'grok-4.7',
+      'grok-4.7-build-fast',
       'grok-4.6',
       'grok-4.5',
-      'grok-composer-2.5-fast',
     ])
-    expect(GROK_DEFAULT_MAIN_MODEL).toBe('grok-4.6')
+    expect(GROK_DEFAULT_MAIN_MODEL).toBe('grok-4.7')
     expect(resolveGrokModel('claude-opus-4-1')).toBe(GROK_DEFAULT_MAIN_MODEL)
   })
 
   test('preserves remote model IDs and resolves only Claude compatibility aliases', () => {
-    expect(resolveGrokModel('grok-composer-2.5-fast')).toBe('grok-composer-2.5-fast')
     expect(resolveGrokModel('grok')).toBe(GROK_DEFAULT_MAIN_MODEL)
     expect(resolveGrokModel('grok-next-preview')).toBe('grok-next-preview')
     expect(resolveGrokModel('unknown-model')).toBe('unknown-model')
+    expect(getGrokContextWindowForModel('grok-4.7')).toBe(500_000)
+    expect(getGrokContextWindowForModel('grok-4.7-build-fast')).toBe(500_000)
     expect(getGrokContextWindowForModel('grok-4.6')).toBe(500_000)
     expect(getGrokContextWindowForModel('grok-4.5')).toBe(500_000)
     expect(getGrokContextWindowForModel('unknown-model')).toBeNull()
   })
 
-  test('normalizes reasoning effort through the selected model catalog', () => {
-    expect(resolveGrokReasoningEffort('grok-4.6', 'xhigh')).toBe('xhigh')
-    expect(resolveGrokReasoningEffort('grok-4.6', 'max')).toBe('high')
+  test('normalizes reasoning effort through the bundled catalog', () => {
+    expect(resolveGrokReasoningEffort('grok-4.7', 'xhigh')).toBe('xhigh')
+    expect(resolveGrokReasoningEffort('grok-4.7', 'max')).toBe('high')
     expect(resolveGrokReasoningEffort('grok-4.5', 'low')).toBe('low')
     expect(resolveGrokReasoningEffort('grok-4.5', 'max')).toBe('high')
-    expect(resolveGrokReasoningEffort('grok-composer-2.5-fast', 'high')).toBeUndefined()
+  })
+
+  test('resolves effort for a model only the live catalog describes', () => {
+    // Regression: a model newer than this build is absent from the bundled
+    // catalog, so resolving against bundled entries alone returned undefined and
+    // the request transform deleted the whole reasoning block.
+    setGrokRuntimeModelCatalog([
+      {
+        value: 'grok-4.8',
+        label: 'Grok 4.8',
+        description: '',
+        contextWindow: 500_000,
+        supportsReasoningEffort: true,
+        reasoningEffort: 'high',
+        reasoningEfforts: ['xhigh', 'high', 'low'],
+      },
+    ])
+    const catalog = getGrokRuntimeModelCatalog()
+    expect(resolveGrokReasoningEffort('grok-4.8', 'xhigh', catalog)).toBe('xhigh')
+    expect(resolveGrokReasoningEffort('grok-4.8', 'low', catalog)).toBe('low')
+    expect(resolveGrokReasoningEffort('grok-4.8', 'medium', catalog)).toBe('high')
+  })
+
+  test('honors a live declaration that a model rejects reasoning effort', () => {
+    setGrokRuntimeModelCatalog([
+      {
+        value: 'grok-4.8',
+        label: 'Grok 4.8',
+        description: '',
+        supportsReasoningEffort: false,
+      },
+    ])
+    expect(
+      resolveGrokReasoningEffort('grok-4.8', 'high', getGrokRuntimeModelCatalog()),
+    ).toBeUndefined()
+  })
+
+  test('forwards the requested effort for a model neither catalog describes', () => {
+    expect(resolveGrokReasoningEffort('grok-4.9-preview', 'xhigh')).toBe('xhigh')
+    expect(resolveGrokReasoningEffort('grok-4.9-preview', undefined)).toBeUndefined()
   })
 })
diff --git a/src/services/grokAuth/models.ts b/src/services/grokAuth/models.ts
index c8a1c4df..b2eda1c8 100644
--- a/src/services/grokAuth/models.ts
+++ b/src/services/grokAuth/models.ts
@@ -1,4 +1,4 @@
-export const GROK_DEFAULT_MAIN_MODEL = 'grok-4.6'
+export const GROK_DEFAULT_MAIN_MODEL = 'grok-4.7'
 export const GROK_DEFAULT_SONNET_MODEL = GROK_DEFAULT_MAIN_MODEL
 export const GROK_DEFAULT_HAIKU_MODEL = GROK_DEFAULT_MAIN_MODEL
 export const GROK_DEFAULT_MODEL = GROK_DEFAULT_MAIN_MODEL
@@ -17,7 +17,19 @@ export type GrokModelCatalogEntry = {
 
 export const GROK_MODEL_CATALOG: GrokModelCatalogEntry[] = [
   {
-    ...model('grok-4.6', 'Grok 4.6', "SpaceXAI's latest frontier model", 500_000),
+    ...model('grok-4.7', 'Grok 4.7', "SpaceXAI's latest frontier model", 500_000),
+    supportsReasoningEffort: true,
+    reasoningEffort: 'high',
+    reasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
+  },
+  {
+    ...model('grok-4.7-build-fast', 'Grok 4.7 Fast', 'Fast variant. 2x the price.', 500_000),
+    supportsReasoningEffort: true,
+    reasoningEffort: 'high',
+    reasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
+  },
+  {
+    ...model('grok-4.6', 'Grok 4.6', 'Grok 4.6 frontier model', 500_000),
     supportsReasoningEffort: true,
     reasoningEffort: 'high',
     reasoningEfforts: ['xhigh', 'high', 'medium', 'low'],
@@ -28,10 +40,6 @@ export const GROK_MODEL_CATALOG: GrokModelCatalogEntry[] = [
     reasoningEffort: 'high',
     reasoningEfforts: ['high', 'medium', 'low'],
   },
-  {
-    ...model('grok-composer-2.5-fast', 'Composer 2.5', 'Grok coding model', 200_000),
-    supportsReasoningEffort: false,
-  },
 ]
 
 function model(
@@ -44,6 +52,28 @@ function model(
   return { value, label, description, contextWindow, source }
 }
 
+/**
+ * The catalog as last seen from the live `/v1/models` feed, falling back to the
+ * bundled entries until that fetch lands.
+ *
+ * This state lives here rather than in `modelCatalog.ts` because that module
+ * builds its request endpoint from `fetch.ts`, and the request transform in
+ * `fetch.ts` needs to read the live catalog. Keeping the pointer in the
+ * dependency-free catalog module is what lets both sides share it without an
+ * import cycle.
+ */
+let runtimeCatalog: readonly GrokModelCatalogEntry[] = GROK_MODEL_CATALOG
+
+export function setGrokRuntimeModelCatalog(
+  models: readonly GrokModelCatalogEntry[],
+): void {
+  runtimeCatalog = models
+}
+
+export function getGrokRuntimeModelCatalog(): readonly GrokModelCatalogEntry[] {
+  return runtimeCatalog
+}
+
 const EXPLICIT_MODELS = new Set(GROK_MODEL_CATALOG.map((entry) => entry.value))
 const CLAUDE_COMPATIBILITY_ALIASES = new Set([
   'default',
@@ -76,18 +106,35 @@ export function getGrokContextWindowForModel(modelId: string): number | null {
   return GROK_MODEL_CATALOG.find((model) => model.value === resolved)?.contextWindow ?? null
 }
 
+/**
+ * `catalog` is the live `/v1/models` view. The bundled catalog is only a
+ * fallback, so a model that exists upstream but predates this build must be
+ * resolved against the live entries or every future model launch silently
+ * degrades its effort to the upstream default.
+ */
 export function resolveGrokReasoningEffort(
   modelId: string,
   requestedEffort: unknown,
+  catalog: readonly GrokModelCatalogEntry[] = GROK_MODEL_CATALOG,
 ): string | undefined {
   const resolved = resolveGrokModel(modelId)
-  const model = GROK_MODEL_CATALOG.find((entry) => entry.value === resolved)
-  if (model?.supportsReasoningEffort === false) return undefined
-  if (
-    typeof requestedEffort === 'string' &&
-    model?.reasoningEfforts?.includes(requestedEffort)
-  ) {
-    return requestedEffort
+  const model =
+    catalog.find((entry) => entry.value === resolved) ??
+    GROK_MODEL_CATALOG.find((entry) => entry.value === resolved)
+  if (model) {
+    if (model.supportsReasoningEffort === false) return undefined
+    if (
+      typeof requestedEffort === 'string' &&
+      model.reasoningEfforts?.includes(requestedEffort)
+    ) {
+      return requestedEffort
+    }
+    return model.reasoningEffort
   }
-  return model?.reasoningEffort
+  // Absent from both catalogs, so upstream advertises a model this build does
+  // not describe. The requested effort already went through the OpenAI effort
+  // vocabulary and the server validated it against that same live catalog, so
+  // forward it rather than silently sending a different effort than the user
+  // selected.
+  return typeof requestedEffort === 'string' ? requestedEffort : undefined
 }
diff --git a/src/utils/effort.agent.test.ts b/src/utils/effort.agent.test.ts
index 3798c7b1..9d5f4595 100644
--- a/src/utils/effort.agent.test.ts
+++ b/src/utils/effort.agent.test.ts
@@ -9,6 +9,10 @@ import {
   resolveAppliedEffort,
   toPersistableEffort,
 } from './effort.js'
+import {
+  GROK_MODEL_CATALOG,
+  setGrokRuntimeModelCatalog,
+} from 'src/services/grokAuth/models.js'
 
 describe('agent effort values', () => {
   test('accepts all named agent effort levels including xhigh', () => {
@@ -65,14 +69,13 @@ describe('agent effort values', () => {
     const originalOverride = process.env.CLAUDE_CODE_EFFORT_LEVEL
     delete process.env.CLAUDE_CODE_EFFORT_LEVEL
     try {
-      expect(modelSupportsEffort('grok-4.6')).toBe(true)
-      expect(modelSupportsXHighEffort('grok-4.6')).toBe(true)
-      expect(resolveAppliedEffort('grok-4.6', 'xhigh')).toBe('xhigh')
-      expect(resolveAppliedEffort('grok-4.6', 'max')).toBe('high')
+      expect(modelSupportsEffort('grok-4.7')).toBe(true)
+      expect(modelSupportsXHighEffort('grok-4.7')).toBe(true)
+      expect(resolveAppliedEffort('grok-4.7', 'xhigh')).toBe('xhigh')
+      expect(resolveAppliedEffort('grok-4.7', 'max')).toBe('high')
+      expect(modelSupportsXHighEffort('grok-4.7-build-fast')).toBe(true)
       expect(modelSupportsXHighEffort('grok-4.5')).toBe(false)
       expect(resolveAppliedEffort('grok-4.5', 'xhigh')).toBe('high')
-      expect(modelSupportsEffort('grok-composer-2.5-fast')).toBe(false)
-      expect(resolveAppliedEffort('grok-composer-2.5-fast', 'xhigh')).toBe('high')
     } finally {
       if (originalOverride === undefined) {
         delete process.env.CLAUDE_CODE_EFFORT_LEVEL
@@ -82,6 +85,43 @@ describe('agent effort values', () => {
     }
   })
 
+  test('reads Grok effort capability from the live catalog for an unknown model', () => {
+    // Regression: an ID absent from the bundled catalog used to fall through to
+    // the Claude heuristics, which report a third-party model as
+    // effort-incapable and strip the parameter entirely.
+    const originalOverride = process.env.CLAUDE_CODE_EFFORT_LEVEL
+    delete process.env.CLAUDE_CODE_EFFORT_LEVEL
+    setGrokRuntimeModelCatalog([
+      {
+        value: 'grok-4.8',
+        label: 'Grok 4.8',
+        description: '',
+        supportsReasoningEffort: true,
+        reasoningEffort: 'high',
+        reasoningEfforts: ['xhigh', 'high', 'low'],
+      },
+      {
+        value: 'grok-4.8-non-reasoning',
+        label: 'Grok 4.8 Non-Reasoning',
+        description: '',
+        supportsReasoningEffort: false,
+      },
+    ])
+    try {
+      expect(modelSupportsEffort('grok-4.8')).toBe(true)
+      expect(modelSupportsXHighEffort('grok-4.8')).toBe(true)
+      expect(resolveAppliedEffort('grok-4.8', 'xhigh')).toBe('xhigh')
+      expect(modelSupportsEffort('grok-4.8-non-reasoning')).toBe(false)
+    } finally {
+      setGrokRuntimeModelCatalog(GROK_MODEL_CATALOG)
+      if (originalOverride === undefined) {
+        delete process.env.CLAUDE_CODE_EFFORT_LEVEL
+      } else {
+        process.env.CLAUDE_CODE_EFFORT_LEVEL = originalOverride
+      }
+    }
+  })
+
   test('lets request-scoped Agent effort override session env only when marked', () => {
     const originalOverride = process.env.CLAUDE_CODE_EFFORT_LEVEL
     try {
diff --git a/src/utils/effort.ts b/src/utils/effort.ts
index 28ea44bb..977c71de 100644
--- a/src/utils/effort.ts
+++ b/src/utils/effort.ts
@@ -15,7 +15,7 @@ import {
   getOpenAIModelCatalogEntry,
   isOpenAIResponsesModel,
 } from 'src/services/openaiAuth/models.js'
-import { GROK_MODEL_CATALOG } from 'src/services/grokAuth/models.js'
+import { GROK_MODEL_CATALOG, getGrokRuntimeModelCatalog } from 'src/services/grokAuth/models.js'
 
 export type EffortLevel = RuntimeEffortLevel | 'xhigh'
 
@@ -42,7 +42,14 @@ function shouldTrustBuiltInClaudeCapabilityList(): boolean {
 
 function getGrokCatalogEntry(model: string): (typeof GROK_MODEL_CATALOG)[number] | undefined {
   const normalized = model.trim().toLowerCase()
-  return GROK_MODEL_CATALOG.find((entry) => entry.value === normalized)
+  // The live `/v1/models` feed is authoritative; the bundled entries are only a
+  // fallback. Without this, a Grok model newer than this build matches no entry
+  // and falls through to the Claude heuristics below, which report it as
+  // effort-incapable and silently strip the parameter.
+  return (
+    getGrokRuntimeModelCatalog().find((entry) => entry.value === normalized) ??
+    GROK_MODEL_CATALOG.find((entry) => entry.value === normalized)
+  )
 }
 
 // @[MODEL LAUNCH]: Add the new model to the allowlist if it supports the effort parameter.