From f63e2cd5a31a73c980d199b65eb3a320094c46ae Mon Sep 17 00:00:00 2001
From: Tam Nhu Tran <kaitran.ntt@gmail.com>
Date: Tue, 3 Mar 2026 03:10:21 +0700
Subject: [PATCH] fix(cliproxy): denylist deprecated agy 4.5 models

---
 src/api/services/profile-writer.ts            |  39 ++++++
 src/cliproxy/catalog-cache.ts                 |  17 ++-
 src/cliproxy/composite-validator.ts           |  14 +++
 src/cliproxy/config/env-builder.ts            |  17 ++-
 src/cliproxy/config/generator.ts              |   9 +-
 src/cliproxy/model-id-normalizer.ts           |  59 ++++++---
 src/cliproxy/services/variant-service.ts      |  17 +++
 src/cliproxy/tool-sanitization-proxy.ts       |  15 ++-
 .../routes/cliproxy-stats-routes.ts           |   7 ++
 src/web-server/routes/profile-routes.ts       |  10 +-
 src/web-server/routes/route-helpers.ts        |  62 ++++++++++
 src/web-server/routes/settings-routes.ts      | 115 +++++++++++++++++-
 .../unit/api/profile-writer-denylist.test.ts  |  48 ++++++++
 .../unit/cliproxy/composite-validator.test.ts |  15 ++-
 .../composite-variant-service.test.ts         |  36 +++---
 tests/unit/cliproxy/config-generator.test.js  |   9 +-
 .../cliproxy/env-builder-provider-url.test.ts |  48 +++++++-
 .../unit/cliproxy/model-id-normalizer.test.ts |  33 ++++-
 ...ool-sanitization-proxy-integration.test.ts |  25 ++++
 .../cliproxy/variant-update-service.test.ts   |   9 ++
 ...cliproxy-stats-routes-model-update.test.ts |  27 ++++
 .../route-helpers-model-denylist.test.ts      |  74 +++++++++++
 ...ings-routes-model-canonicalization.test.ts |  82 +++++++++++++
 .../components/cliproxy/cliproxy-dialog.tsx   |  22 ++++
 .../cliproxy/cliproxy-edit-dialog.tsx         |  25 ++++
 .../cliproxy/provider-editor/index.tsx        |  58 ++++++++-
 .../setup/wizard/steps/variant-step.tsx       |  20 ++-
 ui/src/lib/i18n.ts                            |   4 +-
 ui/src/lib/utils.ts                           |  11 +-
 29 files changed, 850 insertions(+), 77 deletions(-)
 create mode 100644 tests/unit/api/profile-writer-denylist.test.ts
 create mode 100644 tests/unit/web-server/route-helpers-model-denylist.test.ts

diff --git a/src/api/services/profile-writer.ts b/src/api/services/profile-writer.ts
index 6e21c2e4..1b9ae1b3 100644
--- a/src/api/services/profile-writer.ts
+++ b/src/api/services/profile-writer.ts
@@ -14,6 +14,12 @@ import {
 import { ensureProfileHooks } from '../../utils/websearch/profile-hook-injector';
 import type { TargetType } from '../../targets/target-adapter';
 import { resolveDroidProvider } from '../../targets/droid-provider';
+import { mapExternalProviderName } from '../../cliproxy/provider-capabilities';
+import {
+  extractProviderFromPathname,
+  getDeniedModelIdReasonForProvider,
+} from '../../cliproxy/model-id-normalizer';
+import type { CLIProxyProvider } from '../../cliproxy/types';
 import type {
   ModelMapping,
   CreateApiProfileResult,
@@ -26,6 +32,34 @@ function isOpenRouterUrl(baseUrl: string): boolean {
   return baseUrl.toLowerCase().includes('openrouter.ai');
 }
 
+function resolveProviderFromBaseUrl(baseUrl: string): CLIProxyProvider | null {
+  if (baseUrl.trim().length === 0) {
+    return null;
+  }
+
+  try {
+    const parsed = new URL(baseUrl);
+    const extracted = extractProviderFromPathname(parsed.pathname);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  } catch {
+    const extracted = extractProviderFromPathname(baseUrl);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  }
+}
+
+function getDeniedModelReason(baseUrl: string, models: ModelMapping): string | null {
+  const provider = resolveProviderFromBaseUrl(baseUrl);
+  if (!provider) return null;
+
+  for (const modelId of [models.default, models.opus, models.sonnet, models.haiku]) {
+    if (modelId.trim().length === 0) continue;
+    const deniedReason = getDeniedModelIdReasonForProvider(modelId, provider);
+    if (deniedReason) return deniedReason;
+  }
+
+  return null;
+}
+
 /** Create settings.json file for API profile (legacy format) */
 function createSettingsFile(
   name: string,
@@ -159,6 +193,11 @@ export function createApiProfile(
   provider?: string
 ): CreateApiProfileResult {
   try {
+    const deniedReason = getDeniedModelReason(baseUrl, models);
+    if (deniedReason) {
+      return { success: false, settingsFile: '', error: deniedReason };
+    }
+
     const settingsFile = `~/.ccs/${name}.settings.json`;
 
     if (isUnifiedMode()) {
diff --git a/src/cliproxy/catalog-cache.ts b/src/cliproxy/catalog-cache.ts
index 948f0b75..13038f2c 100644
--- a/src/cliproxy/catalog-cache.ts
+++ b/src/cliproxy/catalog-cache.ts
@@ -5,6 +5,7 @@ import type { CLIProxyProvider } from './types';
 import type { ModelEntry, ProviderCatalog, ThinkingSupport } from './model-catalog';
 import { MODEL_CATALOG } from './model-catalog';
 import type { RemoteModelInfo, RemoteThinkingSupport } from './management-api-types';
+import { getDeniedModelIdReasonForProvider } from './model-id-normalizer';
 
 const CACHE_FILE_NAME = 'model-catalog-cache.json';
 const CACHE_TTL_MS = 24 * 60 * 60 * 1000; // 24 hours
@@ -143,11 +144,18 @@ export function mergeCatalog(
   provider: CLIProxyProvider,
   remoteModels: RemoteModelInfo[]
 ): ProviderCatalog | undefined {
+  const filteredRemoteModels =
+    provider === 'agy'
+      ? remoteModels.filter(
+          (remoteModel) => !getDeniedModelIdReasonForProvider(remoteModel.id, provider)
+        )
+      : remoteModels;
+
   const staticCatalog = MODEL_CATALOG[provider];
-  if (!staticCatalog && remoteModels.length === 0) return undefined;
+  if (!staticCatalog && filteredRemoteModels.length === 0) return undefined;
 
   const displayName = staticCatalog?.displayName || provider;
-  const defaultModel = staticCatalog?.defaultModel || (remoteModels[0]?.id ?? '');
+  const defaultModel = staticCatalog?.defaultModel || (filteredRemoteModels[0]?.id ?? '');
 
   // Build map of static models by lowercase ID for fast lookup
   const staticMap = new Map<string, ModelEntry>();
@@ -161,7 +169,7 @@ export function mergeCatalog(
   const mergedIds = new Set<string>();
   const mergedModels: ModelEntry[] = [];
 
-  for (const remote of remoteModels) {
+  for (const remote of filteredRemoteModels) {
     const remoteEntry = mapRemoteToModelEntry(remote);
     const staticEntry = staticMap.get(remote.id.toLowerCase());
     mergedIds.add(remote.id.toLowerCase());
@@ -185,6 +193,9 @@ export function mergeCatalog(
   // Add static-only models not in remote
   if (staticCatalog) {
     for (const model of staticCatalog.models) {
+      if (getDeniedModelIdReasonForProvider(model.id, provider)) {
+        continue;
+      }
       if (!mergedIds.has(model.id.toLowerCase())) {
         mergedModels.push(model);
       }
diff --git a/src/cliproxy/composite-validator.ts b/src/cliproxy/composite-validator.ts
index 981b58e0..52b24f3b 100644
--- a/src/cliproxy/composite-validator.ts
+++ b/src/cliproxy/composite-validator.ts
@@ -5,6 +5,7 @@
 
 import { CLIPROXY_SUPPORTED_PROVIDERS, CompositeTierConfig } from '../config/unified-config-types';
 import type { CLIProxyProvider } from './types';
+import { getDeniedModelIdReasonForProvider } from './model-id-normalizer';
 
 export const VALID_COMPOSITE_TIERS = ['opus', 'sonnet', 'haiku'] as const;
 export type CompositeTierName = (typeof VALID_COMPOSITE_TIERS)[number];
@@ -90,6 +91,11 @@ export function validateCompositeTiers(
       return `Invalid provider '${provider}' for tier '${tier}': must be one of ${CLIPROXY_SUPPORTED_PROVIDERS.join(', ')}`;
     }
 
+    const deniedTierModelReason = getDeniedModelIdReasonForProvider(model, provider);
+    if (deniedTierModelReason) {
+      return `Invalid model for tier '${tier}': ${deniedTierModelReason}`;
+    }
+
     if (tierValue.fallback !== undefined) {
       const fallback = tierValue.fallback;
       if (!isRecord(fallback)) {
@@ -108,6 +114,14 @@ export function validateCompositeTiers(
         return `Invalid fallback provider '${fallback.provider}' for tier '${tier}': must be one of ${CLIPROXY_SUPPORTED_PROVIDERS.join(', ')}`;
       }
 
+      const deniedFallbackReason = getDeniedModelIdReasonForProvider(
+        fallback.model,
+        fallback.provider
+      );
+      if (deniedFallbackReason) {
+        return `Invalid fallback model for tier '${tier}': ${deniedFallbackReason}`;
+      }
+
       if (fallback.provider === provider && fallback.model === model) {
         return `Circular fallback in tier '${tier}': fallback cannot point to same provider and model`;
       }
diff --git a/src/cliproxy/config/env-builder.ts b/src/cliproxy/config/env-builder.ts
index cca3b409..fb89ef34 100644
--- a/src/cliproxy/config/env-builder.ts
+++ b/src/cliproxy/config/env-builder.ts
@@ -23,6 +23,7 @@ import { getProviderSettingsPath } from './path-resolver';
 import {
   canonicalizeModelIdForProvider,
   MODEL_ENV_VAR_KEYS,
+  migrateDeniedAntigravityModelAliases,
   normalizeModelEnvVarsForProvider,
   normalizeModelIdForProvider,
 } from '../model-id-normalizer';
@@ -79,6 +80,9 @@ function migrateDeprecatedModelNames(
       canonical = UPSTREAM_MODEL_PREFIX + canonical.slice(DEPRECATED_MODEL_PREFIX.length);
     }
     canonical = normalizeModelIdForProvider(canonical, provider);
+    if (provider === 'agy') {
+      canonical = migrateDeniedAntigravityModelAliases(canonical);
+    }
 
     if (canonical !== value) {
       settings.env[key] = canonical;
@@ -94,7 +98,8 @@ function migrateDeprecatedModelNames(
       for (const key of PRESET_MODEL_KEYS) {
         const value = presetRecord[key];
         if (typeof value !== 'string') continue;
-        const canonical = normalizeModelIdForProvider(value, provider);
+        let canonical = normalizeModelIdForProvider(value, provider);
+        canonical = migrateDeniedAntigravityModelAliases(canonical);
         if (canonical !== value) {
           presetRecord[key] = canonical;
           migrated = true;
@@ -564,7 +569,10 @@ export function ensureProviderSettings(provider: CLIProxyProvider): void {
   for (const key of MODEL_ENV_VAR_KEYS) {
     const current = mergedEnv[key];
     if (typeof current !== 'string' || current.trim().length === 0) continue;
-    const canonical = canonicalizeModelIdForProvider(current, provider);
+    let canonical = canonicalizeModelIdForProvider(current, provider);
+    if (provider === 'agy') {
+      canonical = migrateDeniedAntigravityModelAliases(canonical);
+    }
     if (canonical !== current) {
       mergedEnv[key] = canonical;
       mutated = true;
@@ -579,7 +587,10 @@ export function ensureProviderSettings(provider: CLIProxyProvider): void {
       for (const key of PRESET_MODEL_KEYS) {
         const value = presetRecord[key];
         if (typeof value !== 'string') continue;
-        const canonical = canonicalizeModelIdForProvider(value, provider);
+        let canonical = canonicalizeModelIdForProvider(value, provider);
+        if (provider === 'agy') {
+          canonical = migrateDeniedAntigravityModelAliases(canonical);
+        }
         if (canonical !== value) {
           presetRecord[key] = canonical;
           mutated = true;
diff --git a/src/cliproxy/config/generator.ts b/src/cliproxy/config/generator.ts
index b6f9a8e9..3a7729e0 100644
--- a/src/cliproxy/config/generator.ts
+++ b/src/cliproxy/config/generator.ts
@@ -11,6 +11,7 @@ import { getModelMappingFromConfig } from '../base-config-loader';
 import { loadOrCreateUnifiedConfig } from '../../config/unified-config-loader';
 import { getEffectiveApiKey, getEffectiveManagementSecret } from '../auth-token-manager';
 import { getCachedCatalog } from '../catalog-cache';
+import { getDeniedModelIdReasonForProvider } from '../model-id-normalizer';
 import { getAuthDir, getProviderAuthDir, getConfigPathForPort } from './path-resolver';
 import { CLIPROXY_DEFAULT_PORT } from './port-manager';
 
@@ -33,8 +34,9 @@ export const CCS_CONTROL_PANEL_SECRET = 'ccs';
  * v9: Added resilient alias compatibility expansion and cache-assisted alias enrichment
  * v10: Migrated deprecated gemini-claude-* aliases to upstream claude-* aliases
  * v11: Migrated deprecated claude-sonnet-4-6-thinking aliases to claude-sonnet-4-6
+ * v12: Removed denylisted Antigravity Claude 4.5 aliases
  */
-export const CLIPROXY_CONFIG_VERSION = 11;
+export const CLIPROXY_CONFIG_VERSION = 12;
 
 interface OAuthModelAliasEntry {
   name: string;
@@ -63,9 +65,6 @@ const DEFAULT_ANTIGRAVITY_ALIASES: OAuthModelAliasEntry[] = [
   { name: 'claude-sonnet-4-6', alias: 'claude-sonnet-4-6', fork: true },
   // Backward compatibility: legacy sonnet thinking alias now routes to canonical model ID.
   { name: 'claude-sonnet-4-6-thinking', alias: 'claude-sonnet-4-6', fork: true },
-  { name: 'claude-sonnet-4-5', alias: 'claude-sonnet-4-5', fork: true },
-  { name: 'claude-sonnet-4-5-thinking', alias: 'claude-sonnet-4-5-thinking', fork: true },
-  { name: 'claude-opus-4-5-thinking', alias: 'claude-opus-4-5-thinking', fork: true },
   { name: 'claude-opus-4-6-thinking', alias: 'claude-opus-4-6-thinking', fork: true },
 ];
 
@@ -134,6 +133,8 @@ function addAliasEntry(
     fork: entry.fork || undefined,
   };
   if (!normalized.name || !normalized.alias) return;
+  if (getDeniedModelIdReasonForProvider(normalized.name, 'agy')) return;
+  if (getDeniedModelIdReasonForProvider(normalized.alias, 'agy')) return;
 
   const key = `${normalized.name}\u0000${normalized.alias}`;
   const existingIndex = indexByKey.get(key);
diff --git a/src/cliproxy/model-id-normalizer.ts b/src/cliproxy/model-id-normalizer.ts
index 4c94d105..15e4ad60 100644
--- a/src/cliproxy/model-id-normalizer.ts
+++ b/src/cliproxy/model-id-normalizer.ts
@@ -23,12 +23,13 @@ const CLAUDE_DOTTED_THINKING_REGEX =
 const DEPRECATED_ANTIGRAVITY_SONNET_46_THINKING_REGEX =
   /claude-sonnet-4(?:[.-])6-thinking(?=(?:$|-|\[|\(|\/))/gi;
 const CANONICAL_ANTIGRAVITY_SONNET_46_MODEL = 'claude-sonnet-4-6';
-const DEPRECATED_ANTIGRAVITY_OPUS_45_THINKING_REGEX =
-  /claude-opus-4(?:[.-])5-thinking(?=(?:$|-|\[|\(|\/))/gi;
-const CANONICAL_ANTIGRAVITY_OPUS_46_THINKING_MODEL = 'claude-opus-4-6-thinking';
-const DEPRECATED_ANTIGRAVITY_SONNET_45_THINKING_REGEX =
-  /claude-sonnet-4(?:[.-])5-thinking(?=(?:$|-|\[|\(|\/))/gi;
-const DEPRECATED_ANTIGRAVITY_SONNET_45_REGEX = /claude-sonnet-4(?:[.-])5(?=(?:$|-|\[|\(|\/))/gi;
+const DENIED_ANTIGRAVITY_MODEL_REGEX =
+  /claude-(?:opus|sonnet)-4(?:[.-])5(?:-thinking)?(?=(?:$|[^a-z0-9]))/i;
+const DENIED_ANTIGRAVITY_OPUS_45_REGEX =
+  /claude-opus-4(?:[.-])5(?:-thinking)?(?=(?:$|[^a-z0-9]))/gi;
+const DENIED_ANTIGRAVITY_SONNET_45_REGEX =
+  /claude-sonnet-4(?:[.-])5(?:-thinking)?(?=(?:$|[^a-z0-9]))/gi;
+const CANONICAL_ANTIGRAVITY_OPUS_46_MODEL = 'claude-opus-4-6-thinking';
 const CODEX_EFFORT_SUFFIX_REGEX = /-(xhigh|high|medium)$/i;
 
 function trimModelId(model: string): string {
@@ -92,17 +93,41 @@ export function normalizeClaudeDottedThinkingMajorMinor(model: string): string {
  * Canonicalize legacy aliases to `claude-sonnet-4-6` while preserving suffixes.
  */
 export function normalizeDeprecatedAntigravityModelAliases(model: string): string {
-  return model
-    .replace(
-      DEPRECATED_ANTIGRAVITY_OPUS_45_THINKING_REGEX,
-      CANONICAL_ANTIGRAVITY_OPUS_46_THINKING_MODEL
-    )
-    .replace(DEPRECATED_ANTIGRAVITY_SONNET_45_THINKING_REGEX, CANONICAL_ANTIGRAVITY_SONNET_46_MODEL)
-    .replace(DEPRECATED_ANTIGRAVITY_SONNET_45_REGEX, CANONICAL_ANTIGRAVITY_SONNET_46_MODEL)
-    .replace(
-      DEPRECATED_ANTIGRAVITY_SONNET_46_THINKING_REGEX,
-      CANONICAL_ANTIGRAVITY_SONNET_46_MODEL
-    );
+  return model.replace(
+    DEPRECATED_ANTIGRAVITY_SONNET_46_THINKING_REGEX,
+    CANONICAL_ANTIGRAVITY_SONNET_46_MODEL
+  );
+}
+
+/**
+ * Migrate denylisted Antigravity Claude 4.5 aliases to supported Claude 4.6 IDs.
+ * This is intended for repairing stale local settings at runtime.
+ */
+export function migrateDeniedAntigravityModelAliases(model: string): string {
+  const normalized = normalizeClaudeDottedMajorMinor(trimModelId(model));
+  return normalized
+    .replace(DENIED_ANTIGRAVITY_OPUS_45_REGEX, CANONICAL_ANTIGRAVITY_OPUS_46_MODEL)
+    .replace(DENIED_ANTIGRAVITY_SONNET_45_REGEX, CANONICAL_ANTIGRAVITY_SONNET_46_MODEL);
+}
+
+/**
+ * Deprecated Antigravity models that are denylisted and should not be used.
+ */
+export function isDeniedAntigravityModelId(model: string): boolean {
+  return DENIED_ANTIGRAVITY_MODEL_REGEX.test(trimModelId(model));
+}
+
+/**
+ * Returns deny reason when model ID is blocked for the given provider.
+ */
+export function getDeniedModelIdReasonForProvider(
+  model: string,
+  provider: ProviderLike
+): string | null {
+  if (!isAntigravityProvider(provider)) return null;
+  const normalized = normalizeClaudeDottedMajorMinor(trimModelId(model));
+  if (!isDeniedAntigravityModelId(normalized)) return null;
+  return 'Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.';
 }
 
 /**
diff --git a/src/cliproxy/services/variant-service.ts b/src/cliproxy/services/variant-service.ts
index fbb917a6..c16dbe94 100644
--- a/src/cliproxy/services/variant-service.ts
+++ b/src/cliproxy/services/variant-service.ts
@@ -20,6 +20,7 @@ import { hasActiveSessions, deleteSessionLockForPort } from '../session-tracker'
 import { warn } from '../../utils/ui';
 import { getCcsDir } from '../../utils/config-manager';
 import { validateCompositeTiers } from '../composite-validator';
+import { getDeniedModelIdReasonForProvider } from '../model-id-normalizer';
 import {
   createSettingsFile,
   createSettingsFileUnified,
@@ -115,6 +116,11 @@ export function createVariant(
   target: TargetType = 'claude'
 ): VariantOperationResult {
   try {
+    const deniedModelReason = getDeniedModelIdReasonForProvider(model, provider);
+    if (deniedModelReason) {
+      return { success: false, error: deniedModelReason };
+    }
+
     // Validate provider/backend compatibility (block kiro/ghcp on original backend)
     const backendError = validateProviderBackend(provider);
     if (backendError) {
@@ -255,6 +261,17 @@ export function updateVariant(name: string, updates: UpdateVariantOptions): Vari
       };
     }
 
+    if (hasModelUpdate) {
+      const providerForModelUpdate = updates.provider ?? (existing.provider as CLIProxyProfileName);
+      const deniedModelReason = getDeniedModelIdReasonForProvider(
+        updates.model?.trim() || '',
+        providerForModelUpdate
+      );
+      if (deniedModelReason) {
+        return { success: false, error: deniedModelReason };
+      }
+    }
+
     // Update settings file
     if (existing.settings) {
       const settingsPath = existing.settings.replace(/^~/, os.homedir());
diff --git a/src/cliproxy/tool-sanitization-proxy.ts b/src/cliproxy/tool-sanitization-proxy.ts
index 3dc0b379..2c9e31c1 100644
--- a/src/cliproxy/tool-sanitization-proxy.ts
+++ b/src/cliproxy/tool-sanitization-proxy.ts
@@ -18,7 +18,11 @@ import * as os from 'os';
 import { URL } from 'url';
 import { ToolNameMapper, type Tool, type ContentBlock } from './tool-name-mapper';
 import { sanitizeToolSchemas } from './schema-sanitizer';
-import { extractProviderFromPathname, normalizeModelIdForRouting } from './model-id-normalizer';
+import {
+  extractProviderFromPathname,
+  getDeniedModelIdReasonForProvider,
+  normalizeModelIdForRouting,
+} from './model-id-normalizer';
 import { getCcsDir } from '../utils/config-manager';
 
 export interface ToolSanitizationProxyConfig {
@@ -211,6 +215,15 @@ export class ToolSanitizationProxy {
       let modifiedBody = parsed;
       if (isRecord(modifiedBody) && typeof modifiedBody.model === 'string') {
         const providerFromPath = extractProviderFromPathname(fullUpstreamUrl.pathname);
+        const deniedReason = getDeniedModelIdReasonForProvider(
+          modifiedBody.model,
+          providerFromPath
+        );
+        if (deniedReason) {
+          res.writeHead(400, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify({ error: deniedReason }));
+          return;
+        }
         const normalizedModel = normalizeModelIdForRouting(modifiedBody.model, providerFromPath);
         if (normalizedModel !== modifiedBody.model) {
           this.writeLog(
diff --git a/src/web-server/routes/cliproxy-stats-routes.ts b/src/web-server/routes/cliproxy-stats-routes.ts
index 1bd66127..15db9f5c 100644
--- a/src/web-server/routes/cliproxy-stats-routes.ts
+++ b/src/web-server/routes/cliproxy-stats-routes.ts
@@ -54,6 +54,7 @@ import { CLIPROXY_DEFAULT_PORT } from '../../cliproxy/config/port-manager';
 import {
   MODEL_ENV_VAR_KEYS,
   canonicalizeModelIdForProvider,
+  getDeniedModelIdReasonForProvider,
 } from '../../cliproxy/model-id-normalizer';
 
 const router = Router();
@@ -590,6 +591,12 @@ router.put('/models/:provider', async (req: Request, res: Response): Promise<voi
       return;
     }
 
+    const deniedReason = getDeniedModelIdReasonForProvider(model, provider);
+    if (deniedReason) {
+      res.status(400).json({ error: deniedReason });
+      return;
+    }
+
     // Get the settings file for this provider
     const ccsDir = getCliproxyWritablePath();
     const settingsPath = path.join(ccsDir, `${provider}.settings.json`);
diff --git a/src/web-server/routes/profile-routes.ts b/src/web-server/routes/profile-routes.ts
index eb176802..b450c77e 100644
--- a/src/web-server/routes/profile-routes.ts
+++ b/src/web-server/routes/profile-routes.ts
@@ -19,6 +19,10 @@ import { updateSettingsFile } from './route-helpers';
 
 const router = Router();
 
+function isDenylistError(message: string | undefined): boolean {
+  return typeof message === 'string' && message.toLowerCase().includes('denylist');
+}
+
 export function parseTarget(rawTarget: unknown): TargetType | null {
   if (rawTarget === undefined || rawTarget === null || rawTarget === '') {
     return null;
@@ -113,7 +117,8 @@ router.post('/', (req: Request, res: Response): void => {
   );
 
   if (!result.success) {
-    res.status(500).json({ error: result.error || 'Failed to create profile' });
+    const errorMessage = result.error || 'Failed to create profile';
+    res.status(isDenylistError(errorMessage) ? 400 : 500).json({ error: errorMessage });
     return;
   }
 
@@ -203,7 +208,8 @@ router.put('/:name', (req: Request, res: Response): void => {
       ...(hasTargetUpdate && parsedTarget && { target: parsedTarget }),
     });
   } catch (error) {
-    res.status(500).json({ error: (error as Error).message });
+    const errorMessage = (error as Error).message;
+    res.status(isDenylistError(errorMessage) ? 400 : 500).json({ error: errorMessage });
   }
 });
 
diff --git a/src/web-server/routes/route-helpers.ts b/src/web-server/routes/route-helpers.ts
index 24b54245..ba6934b8 100644
--- a/src/web-server/routes/route-helpers.ts
+++ b/src/web-server/routes/route-helpers.ts
@@ -8,6 +8,12 @@ import { getCcsDir, getConfigPath, loadConfigSafe, loadSettings } from '../../ut
 import { expandPath } from '../../utils/helpers';
 import { getClaudeSettingsPath } from '../../utils/claude-config-path';
 import { resolveDroidProvider } from '../../targets/droid-provider';
+import { mapExternalProviderName } from '../../cliproxy/provider-capabilities';
+import {
+  extractProviderFromPathname,
+  getDeniedModelIdReasonForProvider,
+} from '../../cliproxy/model-id-normalizer';
+import type { CLIProxyProvider } from '../../cliproxy/types';
 import type { Config, Settings } from '../../types/config';
 
 /** Model mapping for API profiles */
@@ -18,6 +24,34 @@ export interface ModelMapping {
   haikuModel?: string;
 }
 
+function resolveProviderFromBaseUrl(baseUrl: unknown): CLIProxyProvider | null {
+  if (typeof baseUrl !== 'string' || baseUrl.trim().length === 0) {
+    return null;
+  }
+
+  try {
+    const parsed = new URL(baseUrl);
+    const extracted = extractProviderFromPathname(parsed.pathname);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  } catch {
+    const extracted = extractProviderFromPathname(baseUrl);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  }
+}
+
+function getDeniedModelReasonForProvider(
+  provider: CLIProxyProvider | null,
+  values: Array<string | undefined>
+): string | null {
+  if (!provider) return null;
+  for (const value of values) {
+    if (typeof value !== 'string' || value.trim().length === 0) continue;
+    const deniedReason = getDeniedModelIdReasonForProvider(value, provider);
+    if (deniedReason) return deniedReason;
+  }
+  return null;
+}
+
 /**
  * Read config safely with fallback.
  * Uses loadConfigSafe which supports both unified (config.yaml) and legacy (config.json).
@@ -70,6 +104,16 @@ export function createSettingsFile(
 ): string {
   const settingsPath = path.join(getCcsDir(), `${name}.settings.json`);
   const { model, opusModel, sonnetModel, haikuModel } = models;
+  const providerFromBaseUrl = resolveProviderFromBaseUrl(baseUrl);
+  const deniedReason = getDeniedModelReasonForProvider(providerFromBaseUrl, [
+    model,
+    opusModel,
+    sonnetModel,
+    haikuModel,
+  ]);
+  if (deniedReason) {
+    throw new Error(deniedReason);
+  }
   const droidProvider = resolveDroidProvider({
     provider,
     baseUrl,
@@ -114,6 +158,24 @@ export function updateSettingsFile(
   }
 
   const settings = loadSettings(settingsPath);
+  const providerForValidation =
+    resolveProviderFromBaseUrl(updates.baseUrl) ??
+    resolveProviderFromBaseUrl(settings.env?.ANTHROPIC_BASE_URL);
+  const deniedReason = getDeniedModelReasonForProvider(providerForValidation, [
+    updates.model !== undefined ? updates.model : settings.env?.ANTHROPIC_MODEL,
+    updates.opusModel !== undefined
+      ? updates.opusModel
+      : settings.env?.ANTHROPIC_DEFAULT_OPUS_MODEL,
+    updates.sonnetModel !== undefined
+      ? updates.sonnetModel
+      : settings.env?.ANTHROPIC_DEFAULT_SONNET_MODEL,
+    updates.haikuModel !== undefined
+      ? updates.haikuModel
+      : settings.env?.ANTHROPIC_DEFAULT_HAIKU_MODEL,
+  ]);
+  if (deniedReason) {
+    throw new Error(deniedReason);
+  }
 
   if (updates.baseUrl) {
     settings.env = settings.env || {};
diff --git a/src/web-server/routes/settings-routes.ts b/src/web-server/routes/settings-routes.ts
index 6a9f1bcc..8e3c198e 100644
--- a/src/web-server/routes/settings-routes.ts
+++ b/src/web-server/routes/settings-routes.ts
@@ -27,7 +27,11 @@ import {
 import type { Settings } from '../../types/config';
 import type { CLIProxyProvider } from '../../cliproxy/types';
 import { mapExternalProviderName } from '../../cliproxy/provider-capabilities';
-import { canonicalizeModelIdForProvider } from '../../cliproxy/model-id-normalizer';
+import {
+  canonicalizeModelIdForProvider,
+  extractProviderFromPathname,
+  getDeniedModelIdReasonForProvider,
+} from '../../cliproxy/model-id-normalizer';
 
 const router = Router();
 const MODEL_ENV_KEYS = [
@@ -139,14 +143,89 @@ function resolveProviderForProfile(profileOrVariant: string): CLIProxyProvider |
   return null;
 }
 
-function canonicalizeProfileModelId(profileOrVariant: string, modelId: string): string {
-  const provider = resolveProviderForProfile(profileOrVariant);
+function resolveProviderFromBaseUrl(baseUrl: unknown): CLIProxyProvider | null {
+  if (typeof baseUrl !== 'string' || baseUrl.trim().length === 0) {
+    return null;
+  }
+
+  try {
+    const parsed = new URL(baseUrl);
+    const extracted = extractProviderFromPathname(parsed.pathname);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  } catch {
+    const extracted = extractProviderFromPathname(baseUrl);
+    return extracted ? mapExternalProviderName(extracted) : null;
+  }
+}
+
+function resolveProviderForSettings(
+  profileOrVariant: string,
+  settings?: Pick<Settings, 'env'>
+): CLIProxyProvider | null {
+  const providerFromProfile = resolveProviderForProfile(profileOrVariant);
+  if (providerFromProfile) {
+    return providerFromProfile;
+  }
+
+  const baseUrl =
+    settings?.env && typeof settings.env === 'object' ? settings.env.ANTHROPIC_BASE_URL : undefined;
+  return resolveProviderFromBaseUrl(baseUrl);
+}
+
+function canonicalizeProfileModelId(
+  profileOrVariant: string,
+  modelId: string,
+  settings?: Settings
+): string {
+  const provider = resolveProviderForSettings(profileOrVariant, settings);
   if (!provider) return modelId;
   return canonicalizeModelIdForProvider(modelId, provider);
 }
 
+function findDeniedProfileModel(
+  profileOrVariant: string,
+  modelId: string,
+  settings?: Settings
+): string | null {
+  const provider = resolveProviderForSettings(profileOrVariant, settings);
+  if (!provider) return null;
+  return getDeniedModelIdReasonForProvider(modelId, provider);
+}
+
+function validateProfileSettingsModelDenylist(
+  profileOrVariant: string,
+  settings: Settings
+): string | null {
+  if (settings.env && typeof settings.env === 'object') {
+    for (const key of MODEL_ENV_KEYS) {
+      const value = settings.env[key];
+      if (typeof value !== 'string') continue;
+      const deniedReason = findDeniedProfileModel(profileOrVariant, value, settings);
+      if (deniedReason) {
+        return `${key}: ${deniedReason}`;
+      }
+    }
+  }
+
+  if (!Array.isArray(settings.presets)) return null;
+
+  for (const preset of settings.presets) {
+    for (const key of PRESET_MODEL_KEYS) {
+      const value = preset[key];
+      if (typeof value !== 'string') continue;
+      const deniedReason = findDeniedProfileModel(profileOrVariant, value, settings);
+      if (deniedReason) {
+        const presetName = typeof preset.name === 'string' ? preset.name : 'unnamed';
+        return `Preset '${presetName}' (${key}): ${deniedReason}`;
+      }
+    }
+  }
+
+  return null;
+}
+
 function canonicalizeProfileSettings(profileOrVariant: string, settings: Settings): Settings {
-  const provider = resolveProviderForProfile(profileOrVariant);
+  const provider = resolveProviderForSettings(profileOrVariant, settings);
   if (!provider) return settings;
 
   let changed = false;
@@ -167,13 +246,18 @@ function canonicalizeProfileSettings(profileOrVariant: string, settings: Setting
   }
 
   if (Array.isArray(settings.presets)) {
-    const normalizedPresets = settings.presets.map((preset) => {
+    const normalizedPresets = settings.presets.flatMap((preset) => {
       const normalizedPreset = { ...preset };
       let presetChanged = false;
 
       for (const key of PRESET_MODEL_KEYS) {
         const value = normalizedPreset[key];
         if (typeof value !== 'string') continue;
+        const deniedReason = getDeniedModelIdReasonForProvider(value, provider);
+        if (deniedReason) {
+          changed = true;
+          return [];
+        }
         const canonical = canonicalizeModelIdForProvider(value, provider);
         if (canonical !== value) {
           normalizedPreset[key] = canonical;
@@ -314,6 +398,12 @@ router.put('/:profile', (req: Request, res: Response): void => {
       return;
     }
 
+    const deniedModelReason = validateProfileSettingsModelDenylist(profile, settings as Settings);
+    if (deniedModelReason) {
+      res.status(400).json({ error: deniedModelReason });
+      return;
+    }
+
     const normalizedSettings = canonicalizeProfileSettings(profile, settings as Settings);
 
     // Deduplicate CCS hooks to prevent accumulation (fixes #450)
@@ -437,7 +527,20 @@ router.post('/:profile/presets', (req: Request, res: Response): void => {
     }
 
     const normalizePresetModel = (modelId: string): string =>
-      canonicalizeProfileModelId(profile, modelId);
+      canonicalizeProfileModelId(profile, modelId, settings);
+
+    for (const modelId of [
+      defaultModel,
+      opus || defaultModel,
+      sonnet || defaultModel,
+      haiku || defaultModel,
+    ]) {
+      const deniedReason = findDeniedProfileModel(profile, modelId, settings);
+      if (deniedReason) {
+        res.status(400).json({ error: deniedReason });
+        return;
+      }
+    }
 
     const normalizedDefaultModel = normalizePresetModel(defaultModel);
     const normalizedOpusModel = normalizePresetModel(opus || defaultModel);
diff --git a/tests/unit/api/profile-writer-denylist.test.ts b/tests/unit/api/profile-writer-denylist.test.ts
new file mode 100644
index 00000000..a1975e06
--- /dev/null
+++ b/tests/unit/api/profile-writer-denylist.test.ts
@@ -0,0 +1,48 @@
+import { afterEach, beforeEach, describe, expect, it } from 'bun:test';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { createApiProfile } from '../../../src/api/services/profile-writer';
+
+describe('profile-writer AGY denylist', () => {
+  let tempHome = '';
+  let originalCcsHome: string | undefined;
+
+  beforeEach(() => {
+    tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-profile-writer-'));
+    originalCcsHome = process.env.CCS_HOME;
+    process.env.CCS_HOME = tempHome;
+  });
+
+  afterEach(() => {
+    if (originalCcsHome === undefined) {
+      delete process.env.CCS_HOME;
+    } else {
+      process.env.CCS_HOME = originalCcsHome;
+    }
+
+    if (tempHome && fs.existsSync(tempHome)) {
+      fs.rmSync(tempHome, { recursive: true, force: true });
+    }
+  });
+
+  it('rejects denylisted AGY 4.5 models on profile create', () => {
+    const result = createApiProfile(
+      'agy-denied',
+      'http://127.0.0.1:8317/api/provider/agy',
+      'test-token',
+      {
+        default: 'claude-opus-4.5',
+        opus: 'claude-opus-4.5',
+        sonnet: 'claude-sonnet-4.5',
+        haiku: 'claude-haiku-4.5',
+      },
+      'claude'
+    );
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain('denylist');
+    const settingsPath = path.join(tempHome, '.ccs', 'agy-denied.settings.json');
+    expect(fs.existsSync(settingsPath)).toBe(false);
+  });
+});
diff --git a/tests/unit/cliproxy/composite-validator.test.ts b/tests/unit/cliproxy/composite-validator.test.ts
index 3701b089..d762294d 100644
--- a/tests/unit/cliproxy/composite-validator.test.ts
+++ b/tests/unit/cliproxy/composite-validator.test.ts
@@ -10,7 +10,7 @@ import {
 
 const validTier = {
   provider: 'agy',
-  model: 'claude-sonnet-4-5-thinking',
+  model: 'claude-sonnet-4-6',
 };
 
 describe('validateCompositeDefaultTier', () => {
@@ -77,4 +77,17 @@ describe('validateCompositeTiers', () => {
 
     expect(error).toContain("Circular fallback in tier 'opus'");
   });
+
+  it('rejects denylisted agy 4.5 models', () => {
+    const error = validateCompositeTiers(
+      {
+        opus: { provider: 'agy', model: 'claude-opus-4.5-thinking' },
+        sonnet: { provider: 'gemini', model: 'gemini-2.5-pro' },
+        haiku: { provider: 'gemini', model: 'gemini-2.5-flash' },
+      },
+      { defaultTier: 'opus', requireAllTiers: true }
+    );
+
+    expect(error).toContain('denylist');
+  });
 });
diff --git a/tests/unit/cliproxy/composite-variant-service.test.ts b/tests/unit/cliproxy/composite-variant-service.test.ts
index 22ad8ae8..ccc47fda 100644
--- a/tests/unit/cliproxy/composite-variant-service.test.ts
+++ b/tests/unit/cliproxy/composite-variant-service.test.ts
@@ -73,7 +73,7 @@ cliproxy:
       default_tier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-3-pro-preview' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: 'cliproxy/composite-test.settings.json',
@@ -99,7 +99,7 @@ cliproxy:
 
     expect(result.success).toBe(true);
     expect(result.variant?.tiers?.opus.model).toBe('claude-opus-4-6-thinking');
-    expect(result.variant?.tiers?.sonnet.model).toBe('claude-sonnet-4-5-thinking'); // Unchanged
+    expect(result.variant?.tiers?.sonnet.model).toBe('claude-sonnet-4-6'); // Unchanged
     expect(result.variant?.tiers?.haiku.model).toBe('claude-haiku-4-5-20251001'); // Unchanged
   });
 
@@ -110,7 +110,7 @@ cliproxy:
       default_tier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-3-pro-preview' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: 'cliproxy/composite-test.settings.json',
@@ -144,7 +144,7 @@ cliproxy:
       default_tier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-3-pro-preview' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: 'cliproxy/composite-test.settings.json',
@@ -188,7 +188,7 @@ cliproxy:
           thinking: 'xhigh',
           account: 'team-a',
         },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: 'cliproxy/composite-test.settings.json',
@@ -228,7 +228,7 @@ cliproxy:
       default_tier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-3-pro-preview' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: customSettingsPath,
@@ -244,9 +244,9 @@ cliproxy:
           env: {
             ANTHROPIC_BASE_URL: 'http://127.0.0.1:8318',
             ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
-            ANTHROPIC_MODEL: 'claude-sonnet-4-5-thinking',
+            ANTHROPIC_MODEL: 'claude-sonnet-4-6',
             ANTHROPIC_DEFAULT_OPUS_MODEL: 'gemini-3-pro-preview',
-            ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-5-thinking',
+            ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
             ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
             CUSTOM_ENV: 'preserve-this',
           },
@@ -261,7 +261,7 @@ cliproxy:
 
     const result = updateCompositeVariant('test', {
       tiers: {
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking(high)' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6(high)' },
       },
     });
 
@@ -273,7 +273,7 @@ cliproxy:
       hooks: { PreToolUse: unknown[] };
       customPreset: boolean;
     };
-    expect(updatedSettings.env.ANTHROPIC_MODEL).toBe('claude-sonnet-4-5-thinking(high)');
+    expect(updatedSettings.env.ANTHROPIC_MODEL).toBe('claude-sonnet-4-6(high)');
     expect(updatedSettings.env.CUSTOM_ENV).toBe('preserve-this');
     expect(updatedSettings.hooks.PreToolUse.length).toBe(1);
     expect(updatedSettings.customPreset).toBe(true);
@@ -377,7 +377,7 @@ cliproxy:
       defaultTier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-2.5-pro' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
       } as unknown as {
         opus: { provider: 'gemini' | 'codex' | 'agy'; model: string };
         sonnet: { provider: 'gemini' | 'codex' | 'agy'; model: string };
@@ -395,7 +395,7 @@ cliproxy:
       defaultTier: 'sonnet',
       tiers: {
         opus: null,
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       } as unknown as {
         opus: { provider: 'gemini' | 'codex' | 'agy'; model: string };
@@ -414,7 +414,7 @@ cliproxy:
       defaultTier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-2.5-pro' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
     });
@@ -479,7 +479,7 @@ cliproxy:
       default_tier: 'sonnet',
       tiers: {
         opus: { provider: 'gemini', model: 'gemini-3-pro-preview' },
-        sonnet: { provider: 'agy', model: 'claude-sonnet-4-5-thinking' },
+        sonnet: { provider: 'agy', model: 'claude-sonnet-4-6' },
         haiku: { provider: 'agy', model: 'claude-haiku-4-5-20251001' },
       },
       settings: 'cliproxy/composite-test.settings.json',
@@ -547,7 +547,7 @@ cliproxy:
             model: gemini-3-pro-preview
         sonnet:
           provider: agy
-          model: claude-sonnet-4-5-thinking
+          model: claude-sonnet-4-6
         haiku:
           provider: agy
           model: claude-haiku-4-5-20251001
@@ -588,7 +588,7 @@ cliproxy:
           thinking: xhigh
         sonnet:
           provider: agy
-          model: claude-sonnet-4-5-thinking
+          model: claude-sonnet-4-6
           thinking: medium
         haiku:
           provider: agy
@@ -632,7 +632,7 @@ cliproxy:
           model: claude-opus-4-6-thinking
         sonnet:
           provider: agy
-          model: claude-sonnet-4-5-thinking
+          model: claude-sonnet-4-6
         haiku:
           provider: agy
           model: claude-haiku-4-5-20251001
@@ -671,7 +671,7 @@ cliproxy:
           model: claude-opus-4-6-thinking
         sonnet:
           provider: agy
-          model: claude-sonnet-4-5-thinking
+          model: claude-sonnet-4-6
       settings: cliproxy/bad.settings.json
       port: 8318
     good:
diff --git a/tests/unit/cliproxy/config-generator.test.js b/tests/unit/cliproxy/config-generator.test.js
index 6e3bfd10..751bd766 100644
--- a/tests/unit/cliproxy/config-generator.test.js
+++ b/tests/unit/cliproxy/config-generator.test.js
@@ -584,9 +584,16 @@ auth-dir: "${cliproxyDir.replace(/\\/g, '/')}/auth"
       const config = fs.readFileSync(path.join(cliproxyDir, 'config.yaml'), 'utf-8');
 
       // Claude aliases should have fork: true
-      assert(config.includes('claude-sonnet-4-5'), 'Should include Claude sonnet model');
       assert(config.includes('claude-sonnet-4-6'), 'Should include Claude Sonnet 4.6 model');
       assert(config.includes('fork: true'), 'Should include fork: true for Claude aliases');
+      assert(
+        !config.includes('claude-sonnet-4-5'),
+        'Should not include denylisted Claude Sonnet 4.5 aliases'
+      );
+      assert(
+        !config.includes('claude-opus-4-5'),
+        'Should not include denylisted Claude Opus 4.5 aliases'
+      );
       assert(
         !config.includes('alias: gemini-claude-'),
         'Should not emit deprecated gemini-claude aliases'
diff --git a/tests/unit/cliproxy/env-builder-provider-url.test.ts b/tests/unit/cliproxy/env-builder-provider-url.test.ts
index 6b1efdd7..cc17f718 100644
--- a/tests/unit/cliproxy/env-builder-provider-url.test.ts
+++ b/tests/unit/cliproxy/env-builder-provider-url.test.ts
@@ -118,6 +118,50 @@ describe('getEffectiveEnvVars local provider URL normalization', () => {
     expect(persisted.env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-6');
   });
 
+  it('migrates denylisted AGY 4.5 model IDs to supported 4.6 fallbacks', () => {
+    writeSettings(
+      settingsPath,
+      {
+        ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+        ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
+        ANTHROPIC_MODEL: 'claude-opus-4.5',
+        ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-5-thinking',
+        ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4.5-thinking',
+        ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-sonnet-4-5',
+      },
+      {
+        presets: [
+          {
+            name: 'legacy-45',
+            default: 'claude-opus-4.5',
+            opus: 'claude-opus-4-5-thinking',
+            sonnet: 'claude-sonnet-4.5-thinking',
+            haiku: 'claude-sonnet-4-5',
+          },
+        ],
+      }
+    );
+
+    const env = getEffectiveEnvVars('agy', 8317, settingsPath);
+    expect(env.ANTHROPIC_MODEL).toBe('claude-opus-4-6-thinking');
+    expect(env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('claude-opus-4-6-thinking');
+    expect(env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-6');
+    expect(env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-sonnet-4-6');
+
+    const persisted = JSON.parse(fs.readFileSync(settingsPath, 'utf-8')) as {
+      env: Record<string, string>;
+      presets?: Array<Record<string, string>>;
+    };
+    expect(persisted.env.ANTHROPIC_MODEL).toBe('claude-opus-4-6-thinking');
+    expect(persisted.env.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('claude-opus-4-6-thinking');
+    expect(persisted.env.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-6');
+    expect(persisted.env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-sonnet-4-6');
+    expect(persisted.presets?.[0]?.default).toBe('claude-opus-4-6-thinking');
+    expect(persisted.presets?.[0]?.opus).toBe('claude-opus-4-6-thinking');
+    expect(persisted.presets?.[0]?.sonnet).toBe('claude-sonnet-4-6');
+    expect(persisted.presets?.[0]?.haiku).toBe('claude-sonnet-4-6');
+  });
+
   it('migrates codex preset model mappings to canonical IDs', () => {
     writeSettings(
       settingsPath,
@@ -269,11 +313,11 @@ describe('getEffectiveEnvVars local provider URL normalization', () => {
     expect(repaired.env?.ANTHROPIC_MODEL).toBe('claude-sonnet-4-6(8192)');
     expect(repaired.env?.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('claude-opus-4-6-thinking');
     expect(repaired.env?.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-6');
-    expect(repaired.env?.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-sonnet-4-5');
+    expect(repaired.env?.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-sonnet-4-6');
     expect(repaired.presets?.[0]?.default).toBe('claude-sonnet-4-6');
     expect(repaired.presets?.[0]?.opus).toBe('claude-opus-4-6-thinking');
     expect(repaired.presets?.[0]?.sonnet).toBe('claude-sonnet-4-6');
-    expect(repaired.presets?.[0]?.haiku).toBe('claude-sonnet-4-5');
+    expect(repaired.presets?.[0]?.haiku).toBe('claude-sonnet-4-6');
   });
 
   it('migrates codex effort-suffixed preset IDs during ensureProviderSettings', () => {
diff --git a/tests/unit/cliproxy/model-id-normalizer.test.ts b/tests/unit/cliproxy/model-id-normalizer.test.ts
index 705e8dab..6978d7db 100644
--- a/tests/unit/cliproxy/model-id-normalizer.test.ts
+++ b/tests/unit/cliproxy/model-id-normalizer.test.ts
@@ -2,7 +2,10 @@ import { describe, it, expect } from 'bun:test';
 import {
   canonicalizeModelIdForProvider,
   extractProviderFromPathname,
+  getDeniedModelIdReasonForProvider,
+  isDeniedAntigravityModelId,
   isAntigravityProvider,
+  migrateDeniedAntigravityModelAliases,
   normalizeClaudeDottedMajorMinor,
   normalizeClaudeDottedThinkingMajorMinor,
   normalizeModelIdForProvider,
@@ -65,12 +68,12 @@ describe('model-id-normalizer', () => {
         'claude-opus-4-6-thinking'
       );
       expect(normalizeModelIdForProvider('claude-opus-4.5-thinking', 'agy')).toBe(
-        'claude-opus-4-6-thinking'
+        'claude-opus-4-5-thinking'
       );
       expect(normalizeModelIdForProvider('claude-sonnet-4.5-thinking', 'agy')).toBe(
-        'claude-sonnet-4-6'
+        'claude-sonnet-4-5-thinking'
       );
-      expect(normalizeModelIdForProvider('claude-sonnet-4.5', 'agy')).toBe('claude-sonnet-4-6');
+      expect(normalizeModelIdForProvider('claude-sonnet-4.5', 'agy')).toBe('claude-sonnet-4-5');
       expect(normalizeModelIdForProvider('claude-opus-4.6-thinking', 'gemini')).toBe(
         'claude-opus-4.6-thinking'
       );
@@ -113,9 +116,9 @@ describe('model-id-normalizer', () => {
       };
 
       const normalized = normalizeModelEnvVarsForProvider(input, 'agy');
-      expect(normalized.ANTHROPIC_MODEL).toBe('claude-sonnet-4-6');
-      expect(normalized.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('claude-opus-4-6-thinking');
-      expect(normalized.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-6');
+      expect(normalized.ANTHROPIC_MODEL).toBe('claude-sonnet-4-5-thinking');
+      expect(normalized.ANTHROPIC_DEFAULT_OPUS_MODEL).toBe('claude-opus-4-5-thinking');
+      expect(normalized.ANTHROPIC_DEFAULT_SONNET_MODEL).toBe('claude-sonnet-4-5');
       expect(normalized.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-haiku-4-5');
       expect(normalized.UNRELATED).toBe('keep-me');
 
@@ -123,5 +126,23 @@ describe('model-id-normalizer', () => {
       expect(unchanged.ANTHROPIC_MODEL).toBe('claude-sonnet-4.5-thinking');
       expect(unchanged.UNRELATED).toBe('keep-me');
     });
+
+    it('flags denylisted antigravity models', () => {
+      expect(isDeniedAntigravityModelId('claude-opus-4-5-thinking')).toBe(true);
+      expect(isDeniedAntigravityModelId('claude-sonnet-4.5')).toBe(true);
+      expect(getDeniedModelIdReasonForProvider('claude-sonnet-4.5', 'agy')).toContain('denylist');
+      expect(getDeniedModelIdReasonForProvider('claude-sonnet-4.5', 'gemini')).toBeNull();
+      expect(getDeniedModelIdReasonForProvider('claude-haiku-4.5', 'agy')).toBeNull();
+    });
+
+    it('migrates denylisted antigravity IDs to supported 4.6 fallbacks', () => {
+      expect(migrateDeniedAntigravityModelAliases('claude-opus-4.5')).toBe(
+        'claude-opus-4-6-thinking'
+      );
+      expect(migrateDeniedAntigravityModelAliases('claude-sonnet-4-5-thinking(8192)')).toBe(
+        'claude-sonnet-4-6(8192)'
+      );
+      expect(migrateDeniedAntigravityModelAliases('claude-haiku-4-5')).toBe('claude-haiku-4-5');
+    });
   });
 });
diff --git a/tests/unit/cliproxy/tool-sanitization-proxy-integration.test.ts b/tests/unit/cliproxy/tool-sanitization-proxy-integration.test.ts
index a07ee192..1e35be92 100644
--- a/tests/unit/cliproxy/tool-sanitization-proxy-integration.test.ts
+++ b/tests/unit/cliproxy/tool-sanitization-proxy-integration.test.ts
@@ -253,6 +253,31 @@ describe('ToolSanitizationProxy Integration', () => {
       }
     });
 
+    it('rejects denylisted AGY 4.5 model IDs on antigravity provider route', async () => {
+      const proxy = new ToolSanitizationProxy({
+        upstreamBaseUrl: `http://127.0.0.1:${mockUpstreamPort}`,
+      });
+      const port = await proxy.start();
+
+      try {
+        const response = await fetch(`http://127.0.0.1:${port}/api/provider/agy/v1/messages`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({
+            model: 'claude-sonnet-4.5',
+            messages: [{ role: 'user', content: 'test' }],
+          }),
+        });
+
+        expect(response.status).toBe(400);
+        const body = (await response.json()) as { error: string };
+        expect(body.error).toContain('denylist');
+        expect(lastRequest).toBeNull();
+      } finally {
+        proxy.stop();
+      }
+    });
+
     it('does not rewrite AGY legacy aliases on non-AGY provider routes', async () => {
       const proxy = new ToolSanitizationProxy({
         upstreamBaseUrl: `http://127.0.0.1:${mockUpstreamPort}`,
diff --git a/tests/unit/cliproxy/variant-update-service.test.ts b/tests/unit/cliproxy/variant-update-service.test.ts
index ae3874a4..af491a6a 100644
--- a/tests/unit/cliproxy/variant-update-service.test.ts
+++ b/tests/unit/cliproxy/variant-update-service.test.ts
@@ -83,6 +83,15 @@ cliproxy:
     expect(result.error).toContain('Changing provider requires model update');
   });
 
+  it('rejects denylisted AGY 4.5 model updates', () => {
+    const result = updateVariant('demo', {
+      provider: 'agy',
+      model: 'claude-sonnet-4.5',
+    });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain('denylist');
+  });
+
   it('updates provider and regenerates provider-specific core env in same settings file', () => {
     const result = updateVariant('demo', {
       provider: 'codex',
diff --git a/tests/unit/web-server/cliproxy-stats-routes-model-update.test.ts b/tests/unit/web-server/cliproxy-stats-routes-model-update.test.ts
index 1b15727a..28651028 100644
--- a/tests/unit/web-server/cliproxy-stats-routes-model-update.test.ts
+++ b/tests/unit/web-server/cliproxy-stats-routes-model-update.test.ts
@@ -91,6 +91,33 @@ describe('cliproxy-stats-routes model update canonicalization', () => {
     expect(persisted.env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-haiku-4-5');
   });
 
+  it('rejects denylisted AGY 4.5 model updates', async () => {
+    const settingsPath = path.join(tempHome, '.ccs', 'cliproxy', 'agy.settings.json');
+    writeSettings(settingsPath, {
+      ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+      ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
+      ANTHROPIC_MODEL: 'claude-sonnet-4-6',
+      ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-6-thinking',
+      ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
+      ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4-5',
+    });
+
+    const response = await fetch(`${baseUrl}/api/cliproxy/models/agy`, {
+      method: 'PUT',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ model: 'claude-opus-4.5' }),
+    });
+    expect(response.status).toBe(400);
+
+    const body = (await response.json()) as { error: string };
+    expect(body.error).toContain('denylist');
+
+    const persisted = JSON.parse(fs.readFileSync(settingsPath, 'utf8')) as {
+      env: Record<string, string>;
+    };
+    expect(persisted.env.ANTHROPIC_MODEL).toBe('claude-sonnet-4-6');
+  });
+
   it('canonicalizes Codex effort suffix and syncs linked core model env vars', async () => {
     const settingsPath = path.join(tempHome, '.ccs', 'cliproxy', 'codex.settings.json');
     writeSettings(settingsPath, {
diff --git a/tests/unit/web-server/route-helpers-model-denylist.test.ts b/tests/unit/web-server/route-helpers-model-denylist.test.ts
new file mode 100644
index 00000000..c84fa8db
--- /dev/null
+++ b/tests/unit/web-server/route-helpers-model-denylist.test.ts
@@ -0,0 +1,74 @@
+import { afterEach, beforeEach, describe, expect, it } from 'bun:test';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import {
+  createSettingsFile,
+  updateSettingsFile,
+} from '../../../src/web-server/routes/route-helpers';
+
+describe('route-helpers AGY denylist', () => {
+  let tempHome = '';
+  let originalCcsHome: string | undefined;
+
+  beforeEach(() => {
+    tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-route-helpers-'));
+    originalCcsHome = process.env.CCS_HOME;
+    process.env.CCS_HOME = tempHome;
+  });
+
+  afterEach(() => {
+    if (originalCcsHome === undefined) {
+      delete process.env.CCS_HOME;
+    } else {
+      process.env.CCS_HOME = originalCcsHome;
+    }
+
+    if (tempHome && fs.existsSync(tempHome)) {
+      fs.rmSync(tempHome, { recursive: true, force: true });
+    }
+  });
+
+  it('rejects denylisted AGY models on settings create', () => {
+    expect(() =>
+      createSettingsFile(
+        'agy-denied',
+        'http://127.0.0.1:8317/api/provider/agy',
+        'test-token',
+        {
+          model: 'claude-sonnet-4.5',
+          opusModel: 'claude-opus-4.5',
+          sonnetModel: 'claude-sonnet-4.5',
+          haikuModel: 'claude-haiku-4.5',
+        }
+      )
+    ).toThrow(/denylist/i);
+  });
+
+  it('rejects denylisted AGY models on settings update', () => {
+    const settingsDir = path.join(tempHome, '.ccs');
+    fs.mkdirSync(settingsDir, { recursive: true });
+    const settingsPath = path.join(settingsDir, 'agy-profile.settings.json');
+    fs.writeFileSync(
+      settingsPath,
+      JSON.stringify(
+        {
+          env: {
+            ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+            ANTHROPIC_AUTH_TOKEN: 'test-token',
+            ANTHROPIC_MODEL: 'claude-sonnet-4-6',
+            ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-6-thinking',
+            ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
+            ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4-5',
+          },
+        },
+        null,
+        2
+      ) + '\n'
+    );
+
+    expect(() => updateSettingsFile('agy-profile', { model: 'claude-opus-4.5' })).toThrow(
+      /denylist/i
+    );
+  });
+});
diff --git a/tests/unit/web-server/settings-routes-model-canonicalization.test.ts b/tests/unit/web-server/settings-routes-model-canonicalization.test.ts
index 5f7f861c..2cd7e1d8 100644
--- a/tests/unit/web-server/settings-routes-model-canonicalization.test.ts
+++ b/tests/unit/web-server/settings-routes-model-canonicalization.test.ts
@@ -324,6 +324,88 @@ describe('settings-routes model canonicalization', () => {
     expect(persisted.env.ANTHROPIC_DEFAULT_HAIKU_MODEL).toBe('claude-haiku-4-5');
   });
 
+  it('rejects denylisted AGY models on PUT /:profile', async () => {
+    const settingsPath = path.join(tempHome, '.ccs', 'agy.settings.json');
+    writeSettings(settingsPath, { env: {} });
+
+    const response = await fetch(`${baseUrl}/api/settings/agy`, {
+      method: 'PUT',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        settings: {
+          env: {
+            ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+            ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
+            ANTHROPIC_MODEL: 'claude-sonnet-4.5',
+            ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-6-thinking',
+            ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
+            ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4.5',
+          },
+          presets: [],
+        },
+      }),
+    });
+
+    expect(response.status).toBe(400);
+    const body = (await response.json()) as { error?: string };
+    expect(body.error).toContain('denylist');
+  });
+
+  it('rejects denylisted AGY models on POST /:profile/presets', async () => {
+    const settingsPath = path.join(tempHome, '.ccs', 'agy.settings.json');
+    writeSettings(settingsPath, {
+      env: {
+        ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+        ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
+      },
+      presets: [],
+    });
+
+    const response = await fetch(`${baseUrl}/api/settings/agy/presets`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        name: 'legacy',
+        default: 'claude-opus-4.5-thinking',
+      }),
+    });
+
+    expect(response.status).toBe(400);
+    const body = (await response.json()) as { error?: string };
+    expect(body.error).toContain('denylist');
+  });
+
+  it('drops denylisted AGY presets on read canonicalization', async () => {
+    const settingsPath = path.join(tempHome, '.ccs', 'agy.settings.json');
+    writeSettings(settingsPath, {
+      env: {
+        ANTHROPIC_BASE_URL: 'http://127.0.0.1:8317/api/provider/agy',
+        ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
+        ANTHROPIC_MODEL: 'claude-sonnet-4-6',
+      },
+      presets: [
+        {
+          name: 'denylisted',
+          default: 'claude-sonnet-4.5',
+          opus: 'claude-opus-4-6-thinking',
+          sonnet: 'claude-sonnet-4-6',
+          haiku: 'claude-haiku-4.5',
+        },
+      ],
+    });
+
+    const response = await fetch(`${baseUrl}/api/settings/agy/presets`);
+    expect(response.status).toBe(200);
+
+    const body = (await response.json()) as { presets: Array<Record<string, string>> };
+    expect(body.presets.length).toBe(0);
+
+    const persisted = JSON.parse(fs.readFileSync(settingsPath, 'utf8')) as {
+      presets: Array<Record<string, string>>;
+    };
+    expect(persisted.presets.length).toBe(0);
+  });
+
   it('does not crash on malformed non-string preset model values', async () => {
     const settingsPath = path.join(tempHome, '.ccs', 'agy.settings.json');
     writeSettings(settingsPath, {
diff --git a/ui/src/components/cliproxy/cliproxy-dialog.tsx b/ui/src/components/cliproxy/cliproxy-dialog.tsx
index f070eac5..18a57cb5 100644
--- a/ui/src/components/cliproxy/cliproxy-dialog.tsx
+++ b/ui/src/components/cliproxy/cliproxy-dialog.tsx
@@ -14,10 +14,12 @@ import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Tabs, TabsList, TabsTrigger, TabsContent } from '@/components/ui/tabs';
+import { toast } from 'sonner';
 import { useTranslation } from 'react-i18next';
 import { useCreateVariant, useCliproxyAuth } from '@/hooks/use-cliproxy';
 import { usePrivacy } from '@/contexts/privacy-context';
 import { CLIPROXY_PROVIDERS, getProviderDisplayName } from '@/lib/provider-config';
+import { isDeniedAgyModelId } from '@/lib/utils';
 
 const singleProviderSchema = z.object({
   name: z
@@ -68,6 +70,12 @@ const providerOptions = CLIPROXY_PROVIDERS.map((id) => ({
   value: id,
   label: getProviderDisplayName(id),
 }));
+const AGY_DENYLIST_MESSAGE =
+  'Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.';
+
+function isDeniedAgyModelForProvider(provider: string, modelId: string | undefined): boolean {
+  return provider === 'agy' && typeof modelId === 'string' && isDeniedAgyModelId(modelId);
+}
 
 export function CliproxyDialog({ open, onClose }: CliproxyDialogProps) {
   const { t } = useTranslation();
@@ -99,6 +107,12 @@ export function CliproxyDialog({ open, onClose }: CliproxyDialogProps) {
   const providerAccounts = providerAuth?.accounts || [];
 
   const onSubmitSingle = async (data: SingleProviderFormData) => {
+    if (isDeniedAgyModelForProvider(data.provider, data.model)) {
+      singleForm.setError('model', { message: AGY_DENYLIST_MESSAGE });
+      toast.error(AGY_DENYLIST_MESSAGE);
+      return;
+    }
+
     try {
       await createMutation.mutateAsync(data);
       singleForm.reset();
@@ -109,6 +123,14 @@ export function CliproxyDialog({ open, onClose }: CliproxyDialogProps) {
   };
 
   const onSubmitComposite = async (data: CompositeFormData) => {
+    for (const tier of ['opus', 'sonnet', 'haiku'] as const) {
+      const tierConfig = data.tiers[tier];
+      if (!isDeniedAgyModelForProvider(tierConfig.provider, tierConfig.model)) continue;
+      compositeForm.setError(`tiers.${tier}.model`, { message: AGY_DENYLIST_MESSAGE });
+      toast.error(AGY_DENYLIST_MESSAGE);
+      return;
+    }
+
     try {
       await createMutation.mutateAsync({
         name: data.name,
diff --git a/ui/src/components/cliproxy/cliproxy-edit-dialog.tsx b/ui/src/components/cliproxy/cliproxy-edit-dialog.tsx
index ba532a99..07d3b430 100644
--- a/ui/src/components/cliproxy/cliproxy-edit-dialog.tsx
+++ b/ui/src/components/cliproxy/cliproxy-edit-dialog.tsx
@@ -12,10 +12,12 @@ import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Tabs, TabsList, TabsTrigger, TabsContent } from '@/components/ui/tabs';
+import { toast } from 'sonner';
 import { useTranslation } from 'react-i18next';
 import { useUpdateVariant } from '@/hooks/use-cliproxy';
 import { CLIPROXY_PROVIDERS, getProviderDisplayName } from '@/lib/provider-config';
 import type { UpdateVariant, Variant } from '@/lib/api-client';
+import { isDeniedAgyModelId } from '@/lib/utils';
 
 const singleProviderSchema = z.object({
   provider: z.enum(CLIPROXY_PROVIDERS, { message: 'Provider is required' }),
@@ -61,12 +63,18 @@ const providerOptions = CLIPROXY_PROVIDERS.map((id) => ({
 }));
 
 const COMPOSITE_TIERS = ['opus', 'sonnet', 'haiku'] as const;
+const AGY_DENYLIST_MESSAGE =
+  'Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.';
 
 function normalizeOptionalValue(value?: string): string | undefined {
   const trimmed = value?.trim();
   return trimmed ? trimmed : undefined;
 }
 
+function isDeniedAgyModelForProvider(provider: string, modelId: string | undefined): boolean {
+  return provider === 'agy' && typeof modelId === 'string' && isDeniedAgyModelId(modelId);
+}
+
 function isSingleVariantOnlyTargetChange(variant: Variant, data: SingleProviderFormData): boolean {
   const currentTarget = variant.target || 'claude';
   const currentModel = normalizeOptionalValue(variant.model);
@@ -190,6 +198,14 @@ export function CliproxyEditDialog({ variant, open, onOpenChange }: CliproxyEdit
       }
     }
 
+    const nextProvider = payload.provider || data.provider || variant.provider;
+    const nextModelForValidation = payload.model ?? normalizeOptionalValue(data.model);
+    if (isDeniedAgyModelForProvider(nextProvider, nextModelForValidation)) {
+      singleForm.setError('model', { message: AGY_DENYLIST_MESSAGE });
+      toast.error(AGY_DENYLIST_MESSAGE);
+      return;
+    }
+
     if (Object.keys(payload).length === 0) {
       onOpenChange(false);
       return;
@@ -243,6 +259,15 @@ export function CliproxyEditDialog({ variant, open, onOpenChange }: CliproxyEdit
       }
     }
 
+    const tiersToValidate = payload.tiers ?? data.tiers;
+    for (const tier of COMPOSITE_TIERS) {
+      const tierConfig = tiersToValidate[tier];
+      if (!isDeniedAgyModelForProvider(tierConfig.provider, tierConfig.model)) continue;
+      compositeForm.setError(`tiers.${tier}.model`, { message: AGY_DENYLIST_MESSAGE });
+      toast.error(AGY_DENYLIST_MESSAGE);
+      return;
+    }
+
     if (Object.keys(payload).length === 0) {
       onOpenChange(false);
       return;
diff --git a/ui/src/components/cliproxy/provider-editor/index.tsx b/ui/src/components/cliproxy/provider-editor/index.tsx
index b290dbdb..502b8583 100644
--- a/ui/src/components/cliproxy/provider-editor/index.tsx
+++ b/ui/src/components/cliproxy/provider-editor/index.tsx
@@ -17,6 +17,7 @@ import {
   useDeletePreset,
 } from '@/hooks/use-cliproxy';
 import { CLIPROXY_DEFAULT_PORT } from '@/lib/preset-utils';
+import { isDeniedAgyModelId } from '@/lib/utils';
 import i18n from '@/lib/i18n';
 import { usePrivacy } from '@/contexts/privacy-context';
 import { useProviderEditor } from './use-provider-editor';
@@ -57,10 +58,23 @@ export function ProviderEditor({
   const { data: presetsData } = usePresets(provider);
   const createPresetMutation = useCreatePreset();
   const deletePresetMutation = useDeletePreset();
-  const savedPresets = presetsData?.presets || [];
 
   // Use baseProvider for model filtering (for variants, this is the parent provider)
   const modelFilterProvider = baseProvider || provider;
+  const isAgyProvider = modelFilterProvider.toLowerCase() === 'agy';
+
+  const savedPresets = useMemo(() => {
+    const presets = presetsData?.presets || [];
+    if (!isAgyProvider) return presets;
+
+    return presets.filter(
+      (preset) =>
+        !isDeniedAgyModelId(preset.default) &&
+        !isDeniedAgyModelId(preset.opus) &&
+        !isDeniedAgyModelId(preset.sonnet) &&
+        !isDeniedAgyModelId(preset.haiku)
+    );
+  }, [isAgyProvider, presetsData?.presets]);
 
   const providerModels = useMemo(() => {
     if (!modelsData?.models) return [];
@@ -77,10 +91,12 @@ export function ProviderEditor({
     const owners = ownerMap[modelFilterProvider.toLowerCase()] || [
       modelFilterProvider.toLowerCase(),
     ];
-    return modelsData.models.filter((m) =>
-      owners.some((o) => m.owned_by.toLowerCase().includes(o))
-    );
-  }, [modelsData, modelFilterProvider]);
+    return modelsData.models.filter((m) => {
+      if (!owners.some((o) => m.owned_by.toLowerCase().includes(o))) return false;
+      if (!isAgyProvider) return true;
+      return !isDeniedAgyModelId(m.id);
+    });
+  }, [isAgyProvider, modelsData, modelFilterProvider]);
 
   const providerRoute = (baseProvider || provider).toLowerCase();
 
@@ -131,6 +147,19 @@ export function ProviderEditor({
   const effectiveApiKey = authTokens?.apiKey?.value ?? 'ccs-internal-managed';
 
   const handleApplyPreset = (updates: Record<string, string>) => {
+    if (
+      isAgyProvider &&
+      [
+        updates.ANTHROPIC_MODEL,
+        updates.ANTHROPIC_DEFAULT_OPUS_MODEL,
+        updates.ANTHROPIC_DEFAULT_SONNET_MODEL,
+        updates.ANTHROPIC_DEFAULT_HAIKU_MODEL,
+      ].some((modelId) => typeof modelId === 'string' && isDeniedAgyModelId(modelId))
+    ) {
+      toast.error('Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.');
+      return;
+    }
+
     const effectivePort = port ?? CLIPROXY_DEFAULT_PORT;
     updateEnvValues({
       ANTHROPIC_BASE_URL: `http://127.0.0.1:${effectivePort}/api/provider/${providerRoute}`,
@@ -141,6 +170,16 @@ export function ProviderEditor({
   };
 
   const handleCustomPresetApply = (values: ModelMappingValues, presetName?: string) => {
+    if (
+      isAgyProvider &&
+      [values.default, values.opus, values.sonnet, values.haiku].some((modelId) =>
+        isDeniedAgyModelId(modelId)
+      )
+    ) {
+      toast.error('Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.');
+      return;
+    }
+
     const effectivePort = port ?? CLIPROXY_DEFAULT_PORT;
     updateEnvValues({
       ANTHROPIC_BASE_URL: `http://127.0.0.1:${effectivePort}/api/provider/${providerRoute}`,
@@ -159,6 +198,15 @@ export function ProviderEditor({
       toast.error(i18n.t('commonToast.enterPresetName'));
       return;
     }
+    if (
+      isAgyProvider &&
+      [values.default, values.opus, values.sonnet, values.haiku].some((modelId) =>
+        isDeniedAgyModelId(modelId)
+      )
+    ) {
+      toast.error('Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.');
+      return;
+    }
     createPresetMutation.mutate({ profile: provider, data: { name: presetName, ...values } });
     setCustomPresetOpen(false);
   };
diff --git a/ui/src/components/setup/wizard/steps/variant-step.tsx b/ui/src/components/setup/wizard/steps/variant-step.tsx
index 15befb3c..1e185081 100644
--- a/ui/src/components/setup/wizard/steps/variant-step.tsx
+++ b/ui/src/components/setup/wizard/steps/variant-step.tsx
@@ -14,7 +14,7 @@ import {
   SelectValue,
 } from '@/components/ui/select';
 import { ArrowLeft, User } from 'lucide-react';
-import { cn } from '@/lib/utils';
+import { cn, isDeniedAgyModelId } from '@/lib/utils';
 import { PRIVACY_BLUR_CLASS } from '@/contexts/privacy-context';
 import { MODEL_CATALOGS } from '@/lib/model-catalogs';
 import type { VariantStepProps } from '../types';
@@ -40,6 +40,10 @@ export function VariantStep({
   const catalogModels = MODEL_CATALOGS[selectedProvider]?.models || [];
   const isCustomModel = modelName && !catalogModels.some((m) => m.id === modelName);
   const [showCustomInput, setShowCustomInput] = useState(isCustomModel);
+  const deniedCustomModel =
+    selectedProvider === 'agy' && modelName.trim().length > 0
+      ? isDeniedAgyModelId(modelName)
+      : false;
 
   const handleModelSelect = (value: string) => {
     if (value === CUSTOM_MODEL_VALUE) {
@@ -87,10 +91,20 @@ export function VariantStep({
               onChange={(e) => onModelChange(e.target.value)}
               placeholder={t('setupVariant.modelPlaceholder')}
             />
+            {deniedCustomModel && (
+              <p className="text-xs text-destructive">
+                Antigravity denylist: Claude Opus 4.5 and Claude Sonnet 4.5 are deprecated.
+              </p>
+            )}
             <button
               type="button"
               className="text-xs text-primary hover:underline"
-              onClick={() => setShowCustomInput(false)}
+              onClick={() => {
+                setShowCustomInput(false);
+                if (selectedProvider === 'agy' && isDeniedAgyModelId(modelName)) {
+                  onModelChange('');
+                }
+              }}
             >
               {t('setupVariant.choosePresetInstead')}
             </button>
@@ -140,7 +154,7 @@ export function VariantStep({
           <Button variant="ghost" onClick={onSkip}>
             {t('setupVariant.skip')}
           </Button>
-          <Button onClick={onCreate} disabled={!variantName || isPending}>
+          <Button onClick={onCreate} disabled={!variantName || isPending || deniedCustomModel}>
             {isPending ? t('setupVariant.creating') : t('setupVariant.createVariant')}
           </Button>
         </div>
diff --git a/ui/src/lib/i18n.ts b/ui/src/lib/i18n.ts
index 4585d5f1..7738cb44 100644
--- a/ui/src/lib/i18n.ts
+++ b/ui/src/lib/i18n.ts
@@ -110,7 +110,7 @@ const resources = {
         variantNamePlaceholder: 'e.g., my-gemini, g3, flash',
         invokeHintPrefix: 'Use this name to invoke:',
         model: 'Model',
-        modelPlaceholder: 'e.g., gemini-2.5-pro, claude-opus-4-5',
+        modelPlaceholder: 'e.g., gemini-2.5-pro, claude-opus-4-6-thinking',
         choosePresetInstead: 'Choose from presets instead',
         selectModel: 'Select a model',
         customModelName: 'Custom model name...',
@@ -1241,7 +1241,7 @@ const resources = {
         variantNamePlaceholder: '例如：my-gemini、g3、flash',
         invokeHintPrefix: '可通过该名称调用：',
         model: '模型',
-        modelPlaceholder: '例如：gemini-2.5-pro、claude-opus-4-5',
+        modelPlaceholder: '例如：gemini-2.5-pro、claude-opus-4-6-thinking',
         choosePresetInstead: '改为从预设中选择',
         selectModel: '选择模型',
         customModelName: '自定义模型名称...',
diff --git a/ui/src/lib/utils.ts b/ui/src/lib/utils.ts
index 1fbbe124..37650ad7 100644
--- a/ui/src/lib/utils.ts
+++ b/ui/src/lib/utils.ts
@@ -217,10 +217,15 @@ export function getClaudeResetTime<
 }
 
 // Known primary models to show when exhausted (removed from API response)
+const AGY_DENYLIST_REGEX = /claude-(?:opus|sonnet)-4(?:[.-])5(?:-thinking)?(?=(?:$|[^a-z0-9]))/i;
+
+export function isDeniedAgyModelId(modelId: string): boolean {
+  return AGY_DENYLIST_REGEX.test((modelId || '').trim());
+}
+
 const KNOWN_PRIMARY_MODELS = [
-  { name: 'claude-opus-4-5-thinking', displayName: 'Claude Opus 4.5 (Thinking)' },
-  { name: 'claude-sonnet-4-5', displayName: 'Claude Sonnet 4.5' },
-  { name: 'claude-sonnet-4-5-thinking', displayName: 'Claude Sonnet 4.5 (Thinking)' },
+  { name: 'claude-opus-4-6-thinking', displayName: 'Claude Opus 4.6 (Thinking)' },
+  { name: 'claude-sonnet-4-6', displayName: 'Claude Sonnet 4.6' },
   { name: 'gpt-oss-120b', displayName: 'GPT-OSS 120B (Medium)' },
 ];