feat(catalog): add Claude Fable 5 to Anthropic model registry

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

@@ -168,6 +168,19 @@ describe('Model Catalog', () => {
       assert.strictEqual(opus48.extendedContext, true);
     });
 
+    it('includes Claude Fable 5 with adaptive levels and extended context', () => {
+      const { MODEL_CATALOG } = modelCatalog;
+      const fable5 = MODEL_CATALOG.claude.models.find((m) => m.id === 'claude-fable-5');
+      assert(fable5, 'Should include Claude Fable 5');
+      assert.strictEqual(fable5.name, 'Claude Fable 5');
+      // New top tier above Opus; same adaptive thinking surface as Opus 4.8:
+      // Anthropic only accepts effort levels, budget_tokens is rejected with 400.
+      assert.strictEqual(fable5.thinking.type, 'levels');
+      assert.deepStrictEqual(fable5.thinking.levels, ['low', 'medium', 'high', 'xhigh', 'max']);
+      assert.strictEqual(fable5.thinking.maxLevel, 'max');
+      assert.strictEqual(fable5.extendedContext, true);
+    });
+
     it('retains previous 4.5 snapshot models for explicit selection', () => {
       const { MODEL_CATALOG } = modelCatalog;
       const ids = MODEL_CATALOG.claude.models.map((m) => m.id);

src/cliproxy/__tests__/thinking-validator.test.ts

@@ -60,6 +60,15 @@ describe('Thinking Validator', () => {
       expect(result.warning).toBeUndefined();
     });
 
+    it('should treat max as a distinct top tier on Claude Fable 5', () => {
+      // Fable 5 shares Opus 4.8's adaptive thinking surface; max must remain
+      // distinct from xhigh.
+      const result = validateThinking('claude', 'claude-fable-5', 'max');
+      expect(result.valid).toBe(true);
+      expect(result.value).toBe('max');
+      expect(result.warning).toBeUndefined();
+    });
+
     it('should still alias max -> xhigh for models without a max level (backcompat)', () => {
       // Codex catalog uses ['low','medium','high','xhigh'] with maxLevel 'xhigh'.
       // User input "max" should map down to xhigh rather than be rejected.

src/cliproxy/config/thinking-config.ts

@@ -63,6 +63,7 @@ function shouldShowWarnings(thinkingConfig: ThinkingConfig): boolean {
  */
 export function detectTierFromModel(modelName: string): ModelTier {
   const lower = modelName.toLowerCase();
+  if (lower.includes('fable')) return 'opus'; // Fable is the top tier; thinking defaults match Opus
   if (lower.includes('opus')) return 'opus';
   if (lower.includes('haiku')) return 'haiku';
   return 'sonnet'; // Default to sonnet (most common)

src/cliproxy/executor/__tests__/composite-thinking.test.ts

@@ -65,6 +65,13 @@ describe('detectTierFromModel', () => {
     expect(result).toBe('sonnet');
   });
 
+  it('should map Claude Fable 5 to the opus tier', () => {
+    // Fable is the top tier above Opus; auto-mode thinking defaults should
+    // match the opus tier (effort high), not the sonnet fallback.
+    const result = detectTierFromModel('claude-fable-5');
+    expect(result).toBe('opus');
+  });
+
   it('should detect haiku from model name containing "haiku"', () => {
     const result = detectTierFromModel('claude-haiku-4-5-20251001');
     expect(result).toBe('haiku');

src/cliproxy/model-catalog.ts

@@ -369,6 +369,21 @@ export const MODEL_CATALOG: Partial<Record<CLIProxyProvider, ProviderCatalog>> =
     displayName: 'Claude (Anthropic)',
     defaultModel: 'claude-sonnet-4-6',
     models: [
+      {
+        id: 'claude-fable-5',
+        name: 'Claude Fable 5',
+        description: 'Most powerful model',
+        nativeImageInput: true,
+        // New tier above Opus. Same adaptive-thinking surface as Opus 4.8:
+        // Anthropic accepts only effort levels; manual budget_tokens is rejected with 400.
+        thinking: {
+          type: 'levels',
+          levels: ['low', 'medium', 'high', 'xhigh', 'max'],
+          maxLevel: 'max',
+          dynamicAllowed: true,
+        },
+        extendedContext: true,
+      },
       {
         id: 'claude-opus-4-8',
         name: 'Claude Opus 4.8',

src/web-server/model-pricing.ts

@@ -316,6 +316,13 @@ const PRICING_REGISTRY: Record<string, ModelPricing> = {
       fast: OPUS_48_FAST_RATES,
     },
   },
+  // Claude Fable 5 ($10/$50) — most powerful tier, above Opus
+  'claude-fable-5': {
+    inputPerMillion: 10.0,
+    outputPerMillion: 50.0,
+    cacheCreationPerMillion: 12.5,
+    cacheReadPerMillion: 1.0,
+  },
 
   // ---------------------------------------------------------------------------
   // OpenAI Models - Source: better-ccusage

tests/unit/model-pricing.test.ts

@@ -245,6 +245,14 @@ describe('model-pricing', () => {
       expect(opus48.outputPerMillion).toBe(25.0);
     });
 
+    it('should return correct pricing for Claude Fable 5', () => {
+      const fable5 = getModelPricing('claude-fable-5');
+      expect(fable5.inputPerMillion).toBe(10.0);
+      expect(fable5.outputPerMillion).toBe(50.0);
+      expect(fable5.cacheCreationPerMillion).toBe(12.5);
+      expect(fable5.cacheReadPerMillion).toBe(1.0);
+    });
+
     it('should not map unknown future model families onto known family pricing', () => {
       const fallback = getModelPricing('unknown-model-xyz');
 
@@ -355,6 +363,17 @@ describe('model-pricing', () => {
       expect(cost).toBe(36.75); // 5 + 25 + 6.25 + 0.5
     });
 
+    it('should calculate Claude Fable 5 cost including cache token rates', () => {
+      const usage: TokenUsage = {
+        inputTokens: 1_000_000,
+        outputTokens: 1_000_000,
+        cacheCreationTokens: 1_000_000,
+        cacheReadTokens: 1_000_000,
+      };
+      const cost = calculateCost(usage, 'claude-fable-5');
+      expect(cost).toBe(73.5); // 10 + 50 + 12.5 + 1.0
+    });
+
     it('should calculate fast-tier Claude Opus 4.8 cost (2x premium)', () => {
       const usage: TokenUsage = {
         inputTokens: 1_000_000,

ui/src/lib/model-catalogs.ts

@@ -752,6 +752,18 @@ export const MODEL_CATALOGS: Record<string, ProviderCatalog> = {
     displayName: 'Claude (Anthropic)',
     defaultModel: 'claude-sonnet-4-6',
     models: [
+      {
+        id: 'claude-fable-5',
+        name: 'Claude Fable 5',
+        description: 'Most powerful model',
+        extendedContext: true,
+        presetMapping: {
+          default: 'claude-fable-5',
+          opus: 'claude-fable-5',
+          sonnet: 'claude-sonnet-4-6',
+          haiku: 'claude-haiku-4-5-20251001',
+        },
+      },
       {
         id: 'claude-opus-4-8',
         name: 'Claude Opus 4.8',

ui/tests/unit/ui/lib/preset-utils.test.ts

@@ -16,11 +16,12 @@ describe('claude preset utils', () => {
     vi.restoreAllMocks();
   });
 
-  it('keeps the claude catalog default on Sonnet 4.6 while exposing Opus 4.7 and 4.8', () => {
+  it('keeps the claude catalog default on Sonnet 4.6 while exposing Opus 4.7/4.8 and Fable 5', () => {
     const claudeCatalog = MODEL_CATALOGS.claude;
     const ids = claudeCatalog.models.map((model) => model.id);
 
     expect(claudeCatalog.defaultModel).toBe('claude-sonnet-4-6');
+    expect(ids).toContain('claude-fable-5');
     expect(ids).toContain('claude-opus-4-8');
     expect(ids).toContain('claude-opus-4-7');
     expect(ids).toContain('claude-sonnet-4-6');