diff --git a/src/commands/api-command.ts b/src/commands/api-command.ts
index f44f6f49..4d1aae68 100644
--- a/src/commands/api-command.ts
+++ b/src/commands/api-command.ts
@@ -350,7 +350,7 @@ async function handleCreate(args: string[]): Promise<void> {
   }
 
   // Step 4: Model configuration (use preset default if available)
-  const defaultModel = preset?.defaultModel || 'claude-sonnet-4-5-20250929';
+  const defaultModel = preset?.defaultModel || 'claude-sonnet-4-6';
   let model = parsedArgs.model || openRouterModel || preset?.defaultModel;
   if (!model && !parsedArgs.yes && !preset) {
     model = await InteractivePrompt.input('Default model (ANTHROPIC_MODEL)', {
diff --git a/tests/unit/cliproxy/model-catalog.test.js b/tests/unit/cliproxy/model-catalog.test.js
index ee9f5040..0b2b47f2 100644
--- a/tests/unit/cliproxy/model-catalog.test.js
+++ b/tests/unit/cliproxy/model-catalog.test.js
@@ -113,7 +113,6 @@ describe('Model Catalog', () => {
       assert.strictEqual(MODEL_CATALOG.claude.provider, 'claude');
       assert.strictEqual(MODEL_CATALOG.claude.displayName, 'Claude (Anthropic)');
     });
-
     it('has correct default model', () => {
       const { MODEL_CATALOG } = modelCatalog;
       assert.strictEqual(MODEL_CATALOG.claude.defaultModel, 'claude-sonnet-4-6');
@@ -125,6 +124,13 @@ describe('Model Catalog', () => {
       assert(sonnet, 'Should include Claude Sonnet 4.6');
       assert.strictEqual(sonnet.name, 'Claude Sonnet 4.6');
     });
+
+    it('retains previous 4.5 snapshot models for explicit selection', () => {
+      const { MODEL_CATALOG } = modelCatalog;
+      const ids = MODEL_CATALOG.claude.models.map((m) => m.id);
+      assert(ids.includes('claude-opus-4-5-20251101'));
+      assert(ids.includes('claude-sonnet-4-5-20250929'));
+    });
   });
 
   describe('Gemini models', () => {
diff --git a/ui/src/components/profiles/profile-dialog.tsx b/ui/src/components/profiles/profile-dialog.tsx
index b6873580..f880a6e4 100644
--- a/ui/src/components/profiles/profile-dialog.tsx
+++ b/ui/src/components/profiles/profile-dialog.tsx
@@ -18,7 +18,7 @@ import type { Profile } from '@/lib/api-client';
 import { ChevronDown, ChevronRight } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
 
-const DEFAULT_MODEL = 'claude-sonnet-4-5-20250929';
+const DEFAULT_MODEL = 'claude-sonnet-4-6';
 
 const schema = z.object({
   name: z
diff --git a/ui/src/lib/preset-utils.ts b/ui/src/lib/preset-utils.ts
index 1121d5ab..dec9ba6a 100644
--- a/ui/src/lib/preset-utils.ts
+++ b/ui/src/lib/preset-utils.ts
@@ -27,7 +27,7 @@ async function fetchEffectiveApiKey(): Promise<string> {
 
 /**
  * Apply default preset for a provider to its settings
- * Uses the first model's presetMapping or falls back to using defaultModel for all tiers
+ * Uses the catalog default model's preset mapping or falls back to using defaultModel for all tiers
  *
  * @param provider - The provider ID (e.g., 'gemini', 'codex', 'agy')
  * @param port - Optional custom port (defaults to CLIPROXY_DEFAULT_PORT)
@@ -40,9 +40,9 @@ export async function applyDefaultPreset(
   const catalog = MODEL_CATALOGS[provider];
   if (!catalog) return { success: false };
 
-  // Get the first (recommended) model's preset mapping
-  const firstModel = catalog.models[0];
-  const mapping = firstModel?.presetMapping || {
+  const defaultModelEntry =
+    catalog.models.find((model) => model.id === catalog.defaultModel) || catalog.models[0];
+  const mapping = defaultModelEntry?.presetMapping || {
     default: catalog.defaultModel,
     opus: catalog.defaultModel,
     sonnet: catalog.defaultModel,
@@ -72,7 +72,7 @@ export async function applyDefaultPreset(
     });
     return {
       success: res.ok,
-      presetName: firstModel?.name || catalog.defaultModel,
+      presetName: defaultModelEntry?.name || catalog.defaultModel,
     };
   } catch {
     return { success: false };
diff --git a/ui/tests/unit/ui/lib/preset-utils.test.ts b/ui/tests/unit/ui/lib/preset-utils.test.ts
new file mode 100644
index 00000000..460c1e1f
--- /dev/null
+++ b/ui/tests/unit/ui/lib/preset-utils.test.ts
@@ -0,0 +1,44 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { MODEL_CATALOGS } from '@/lib/model-catalogs';
+import { applyDefaultPreset } from '@/lib/preset-utils';
+
+describe('claude preset utils', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.restoreAllMocks();
+  });
+
+  it('keeps the claude catalog default on Sonnet 4.6', () => {
+    const claudeCatalog = MODEL_CATALOGS.claude;
+
+    expect(claudeCatalog.defaultModel).toBe('claude-sonnet-4-6');
+    expect(claudeCatalog.models.map((model) => model.id)).toContain('claude-sonnet-4-6');
+  });
+
+  it('applies the default claude preset from the catalog default model mapping', async () => {
+    const fetchMock = vi
+      .fn()
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ apiKey: { value: 'managed-key' } }),
+      })
+      .mockResolvedValueOnce({ ok: true });
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const result = await applyDefaultPreset('claude');
+
+    expect(result).toEqual({ success: true, presetName: 'Claude Sonnet 4.6' });
+
+    const [, requestInit] = fetchMock.mock.calls[1] ?? [];
+    const body = JSON.parse(String(requestInit?.body));
+
+    expect(body.settings.env).toMatchObject({
+      ANTHROPIC_MODEL: 'claude-sonnet-4-6',
+      ANTHROPIC_DEFAULT_OPUS_MODEL: 'claude-opus-4-6',
+      ANTHROPIC_DEFAULT_SONNET_MODEL: 'claude-sonnet-4-6',
+      ANTHROPIC_DEFAULT_HAIKU_MODEL: 'claude-haiku-4-5-20251001',
+    });
+  });
+});