fix(cliproxy): harden xAI provider contracts

src/cliproxy/__tests__/model-catalog-compat.test.ts

@@ -63,6 +63,18 @@ describe('model-catalog compatibility lookups', () => {
     });
   });
 
+  it('does not export extended-context capability from live xAI context length', () => {
+    const catalog = mergeCatalog('xai', [
+      {
+        id: 'grok-4.3',
+        display_name: 'Grok 4.3',
+        context_length: 2_000_000,
+      },
+    ]);
+
+    expect(catalog?.models[0]?.extendedContext).toBeUndefined();
+  });
+
   it('does not re-add stale static-only models when live catalog data is present', () => {
     const catalog = mergeCatalog('gemini', [
       {

src/cliproxy/__tests__/model-catalog.test.js

@@ -87,6 +87,23 @@ describe('Model Catalog', () => {
         'grok-composer-2.5-fast',
       ]);
     });
+
+    it('does not expose Claude [1m] suffix support for xAI model IDs', () => {
+      const { MODEL_CATALOG, supportsExtendedContext } = modelCatalog;
+
+      for (const model of MODEL_CATALOG.xai.models) {
+        assert.notStrictEqual(
+          model.extendedContext,
+          true,
+          `${model.id} must not advertise extended-context metadata`
+        );
+        assert.strictEqual(
+          supportsExtendedContext('xai', model.id),
+          false,
+          `${model.id} must not advertise [1m] suffix support`
+        );
+      }
+    });
   });
 
   describe('AGY models', () => {

src/cliproxy/auth/__tests__/oauth-process-error-parser.test.ts

@@ -7,6 +7,7 @@ import {
   extractDeviceCodePrompt,
   getExpectedLocalCallback,
   getKiroBuilderIdSelectionInput,
+  resolveDeviceCodeVerificationUrl,
   validateManualCallbackUrl,
 } from '../oauth-process';
 
@@ -24,6 +25,18 @@ Then enter this code: ABCD-1234
       verificationUrl: 'https://accounts.x.ai/oauth2/device?user_code=ABCD-1234',
     });
   });
+
+  it('preserves a parsed xAI verification URL exactly', () => {
+    const parsedUrl = 'https://accounts.x.ai/oauth2/device?user_code=ABCD-1234&source=cliproxy';
+
+    expect(resolveDeviceCodeVerificationUrl('xai', 'ABCD-1234', parsedUrl)).toBe(parsedUrl);
+  });
+
+  it('uses an xAI-specific device URL when upstream output omits the URL', () => {
+    expect(resolveDeviceCodeVerificationUrl('xai', 'ABCD-1234', null)).toBe(
+      'https://accounts.x.ai/oauth2/device?user_code=ABCD-1234'
+    );
+  });
 });
 
 describe('oauth-process stderr parsing', () => {
@@ -49,6 +62,13 @@ describe('oauth-process stderr parsing', () => {
     expect(extractLikelyAuthFailureFromStderr('ghcp', stderr)).toBe('state mismatch');
   });
 
+  it('extracts the current upstream xAI authentication failure format', () => {
+    const stderr =
+      'time="2026-07-18T00:00:00Z" level=error msg="xAI authentication failed: xai device code expired"';
+
+    expect(extractLikelyAuthFailureFromStderr('xai', stderr)).toBe('xai device code expired');
+  });
+
   it('caps extracted message length to prevent noisy broadcasts', () => {
     const longSuffix = 'x'.repeat(400);
     const stderr = `level=error msg="Authentication failed: ${longSuffix}"`;

src/cliproxy/auth/oauth-process.ts

@@ -143,6 +143,20 @@ export function extractDeviceCodePrompt(output: string): {
   };
 }
 
+export function resolveDeviceCodeVerificationUrl(
+  provider: CLIProxyProvider,
+  userCode: string,
+  parsedUrl: string | null
+): string {
+  if (parsedUrl) {
+    return parsedUrl;
+  }
+  if (provider === 'xai') {
+    return `https://accounts.x.ai/oauth2/device?user_code=${encodeURIComponent(userCode)}`;
+  }
+  return 'https://github.com/login/device';
+}
+
 export function isLoopbackHost(hostname: string): boolean {
   const normalized = hostname.replace(/^\[|\]$/g, '').toLowerCase();
   return (
@@ -415,7 +429,11 @@ async function handleStdout(
       state.deviceCodeDisplayed = true;
       log(`Parsed device code: ${state.userCode}`);
 
-      const verificationUrl = devicePrompt.verificationUrl || 'https://github.com/login/device';
+      const verificationUrl = resolveDeviceCodeVerificationUrl(
+        options.provider,
+        state.userCode,
+        devicePrompt.verificationUrl
+      );
 
       // Emit device code event for WebSocket broadcast to UI
       const deviceCodePrompt: DeviceCodePrompt = {
@@ -525,6 +543,7 @@ export function extractLikelyAuthFailureFromLogs(
     });
 
   const providerPatterns: Partial<Record<CLIProxyProvider, RegExp[]>> = {
+    xai: [/xai authentication failed:\s*(.+)/i],
     ghcp: [
       /github copilot authentication failed:\s*(.+)/i,
       /failed to verify copilot access[^:]*:\s*(.+)/i,

src/cliproxy/model-catalog.ts

@@ -325,7 +325,6 @@ export const MODEL_CATALOG: Partial<Record<CLIProxyProvider, ProviderCatalog>> =
         id: 'grok-4.3',
         name: 'Grok 4.3',
         description: 'General-purpose Grok model with a one-million-token context window',
-        extendedContext: true,
         thinking: {
           type: 'levels',
           levels: ['none', 'low', 'medium', 'high'],
@@ -336,19 +335,16 @@ export const MODEL_CATALOG: Partial<Record<CLIProxyProvider, ProviderCatalog>> =
         id: 'grok-4.20-0309-reasoning',
         name: 'Grok 4.20 0309 Reasoning',
         description: 'Reasoning model with a two-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-4.20-0309-non-reasoning',
         name: 'Grok 4.20 0309 Non Reasoning',
         description: 'Non-reasoning model with a two-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-4.20-multi-agent-0309',
         name: 'Grok 4.20 Multi Agent 0309',
         description: 'Multi-agent model with a two-million-token context window',
-        extendedContext: true,
         thinking: { type: 'levels', levels: ['low', 'medium', 'high'] },
       },
       {
@@ -765,6 +761,7 @@ export function supportsThinking(provider: CLIProxyProvider, modelId: string): b
  * Returns true if model has extendedContext: true in catalog.
  */
 export function supportsExtendedContext(provider: CLIProxyProvider, modelId: string): boolean {
+  if (provider === 'xai') return false;
   const model = findModel(provider, modelId);
   return model?.extendedContext === true;
 }

src/cliproxy/services/catalog-cache.ts

@@ -215,13 +215,15 @@ function mapThinking(remote?: RemoteThinkingSupport): ThinkingSupport | undefine
 }
 
 /** Map RemoteModelInfo to ModelEntry */
-function mapRemoteToModelEntry(remote: RemoteModelInfo): ModelEntry {
+function mapRemoteToModelEntry(provider: CLIProxyProvider, remote: RemoteModelInfo): ModelEntry {
   const entry: ModelEntry = {
     id: remote.id,
     name: remote.display_name || remote.id,
   };
   if (remote.description) entry.description = remote.description;
-  if (remote.context_length && remote.context_length >= 1_000_000) {
+  // xAI context length is inherent to the model ID; its API does not accept
+  // Claude's [1m] model suffix.
+  if (provider !== 'xai' && remote.context_length && remote.context_length >= 1_000_000) {
     entry.extendedContext = true;
   }
   const thinking = mapThinking(remote.thinking);
@@ -264,7 +266,7 @@ export function mergeCatalog(
   const mergedModels: ModelEntry[] = [];
 
   for (const remote of filteredRemoteModels) {
-    const remoteEntry = mapRemoteToModelEntry(remote);
+    const remoteEntry = mapRemoteToModelEntry(provider, remote);
     const staticEntry = staticMap.get(remote.id.toLowerCase());
     if (staticEntry) {
       const mergedThinking = remoteEntry.thinking

ui/src/lib/model-catalogs.ts

@@ -407,25 +407,21 @@ export const MODEL_CATALOGS: Record<string, ProviderCatalog> = {
         id: 'grok-4.3',
         name: 'Grok 4.3',
         description: 'General-purpose Grok model with a one-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-4.20-0309-reasoning',
         name: 'Grok 4.20 0309 Reasoning',
         description: 'Reasoning model with a two-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-4.20-0309-non-reasoning',
         name: 'Grok 4.20 0309 Non Reasoning',
         description: 'Non-reasoning model with a two-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-4.20-multi-agent-0309',
         name: 'Grok 4.20 Multi Agent 0309',
         description: 'Multi-agent model with a two-million-token context window',
-        extendedContext: true,
       },
       {
         id: 'grok-3-mini',
@@ -1124,7 +1120,8 @@ export function buildUiCatalog(
   provider: string,
   liveCatalog: ProviderCatalog | undefined
 ): ProviderCatalog | undefined {
-  const staticCatalog = MODEL_CATALOGS[provider.toLowerCase()];
+  const normalizedProvider = provider.toLowerCase();
+  const staticCatalog = MODEL_CATALOGS[normalizedProvider];
   if (!liveCatalog || liveCatalog.models.length === 0) {
     return staticCatalog;
   }
@@ -1145,7 +1142,10 @@ export function buildUiCatalog(
       issueUrl: staticModel?.issueUrl,
       deprecated: staticModel?.deprecated,
       deprecationReason: staticModel?.deprecationReason,
-      extendedContext: model.extendedContext ?? staticModel?.extendedContext,
+      extendedContext:
+        normalizedProvider === 'xai'
+          ? undefined
+          : (model.extendedContext ?? staticModel?.extendedContext),
       presetMapping: staticModel?.presetMapping,
     };
   });
@@ -1344,5 +1344,6 @@ export function supportsExtendedContext(
   modelId: string,
   catalogOverride?: ProviderCatalog
 ): boolean {
+  if (provider.toLowerCase() === 'xai') return false;
   return findCatalogModel(provider, modelId, catalogOverride)?.extendedContext === true;
 }

ui/tests/unit/ui/lib/model-catalogs-xai.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { MODEL_CATALOGS } from '@/lib/model-catalogs';
+import { buildUiCatalog, MODEL_CATALOGS, supportsExtendedContext } from '@/lib/model-catalogs';
 
 describe('xAI model catalog defaults', () => {
   it('mirrors the CLIProxyAPI text catalog and default tier routing', () => {
@@ -27,4 +27,31 @@ describe('xAI model catalog defaults', () => {
       haiku: 'grok-composer-2.5-fast',
     });
   });
+
+  it('does not expose Claude [1m] suffix support for xAI model IDs', () => {
+    const catalog = MODEL_CATALOGS.xai;
+
+    for (const model of catalog.models) {
+      expect(model.extendedContext).not.toBe(true);
+      expect(supportsExtendedContext('xai', model.id)).toBe(false);
+    }
+  });
+
+  it('strips generic extended-context metadata from live xAI catalogs', () => {
+    const catalog = buildUiCatalog('xai', {
+      provider: 'xai',
+      displayName: 'xAI (Grok)',
+      defaultModel: 'grok-4.3',
+      models: [
+        {
+          id: 'grok-4.3',
+          name: 'Grok 4.3',
+          extendedContext: true,
+        },
+      ],
+    });
+
+    expect(catalog?.models[0]?.extendedContext).toBeUndefined();
+    expect(supportsExtendedContext('xai', 'grok-4.3', catalog)).toBe(false);
+  });
 });