🤖 feat: Claude Sonnet 4.6 support (#11829)

* 🤖 feat: Claude Sonnet 4.6 support

- Updated .env.example to include claude-sonnet-4-6 in the list of available models.
- Enhanced token value assignments in api/models/tx.js and packages/api/src/utils/tokens.ts to accommodate claude-sonnet-4-6.
- Added tests in packages/data-provider/specs/bedrock.spec.ts to verify support for claude-sonnet-4-6 in adaptive thinking and context-1m functionalities.
- Modified bedrock.ts to correctly parse and identify the version of claude-sonnet-4-6 for adaptive thinking checks.
- Included claude-sonnet-4-6 in sharedAnthropicModels and bedrockModels for consistent model availability.

* chore: additional Claude Sonnet 4.6 tests

- Added unit tests for Claude Sonnet 4.6 in `tokens.spec.js` to verify context length and max output tokens.
- Updated `helpers.ts` documentation to reflect adaptive thinking support for Sonnet 4.6.
- Enhanced `llm.spec.ts` with tests for context headers and adaptive thinking configurations for Claude Sonnet 4.6.
- Improved `bedrock.spec.ts` to ensure correct parsing and handling of Claude Sonnet 4.6 model variations with adaptive thinking.

.env.example

@@ -135,7 +135,7 @@ PROXY=
 #============#
 
 ANTHROPIC_API_KEY=user_provided
-# ANTHROPIC_MODELS=claude-opus-4-6,claude-opus-4-20250514,claude-sonnet-4-20250514,claude-3-7-sonnet-20250219,claude-3-5-sonnet-20241022,claude-3-5-haiku-20241022,claude-3-opus-20240229,claude-3-sonnet-20240229,claude-3-haiku-20240307
+# ANTHROPIC_MODELS=claude-sonnet-4-6,claude-opus-4-6,claude-opus-4-20250514,claude-sonnet-4-20250514,claude-3-7-sonnet-20250219,claude-3-5-sonnet-20241022,claude-3-5-haiku-20241022,claude-3-opus-20240229,claude-3-sonnet-20240229,claude-3-haiku-20240307
 # ANTHROPIC_REVERSE_PROXY=
 
 # Set to true to use Anthropic models through Google Vertex AI instead of direct API
@@ -170,8 +170,8 @@ ANTHROPIC_API_KEY=user_provided
 # BEDROCK_AWS_SESSION_TOKEN=someSessionToken
 
 # Note: This example list is not meant to be exhaustive. If omitted, all known, supported model IDs will be included for you.
-# BEDROCK_AWS_MODELS=anthropic.claude-opus-4-6-v1,anthropic.claude-3-5-sonnet-20240620-v1:0,meta.llama3-1-8b-instruct-v1:0
-# Cross-region inference model IDs: us.anthropic.claude-opus-4-6-v1,global.anthropic.claude-opus-4-6-v1
+# BEDROCK_AWS_MODELS=anthropic.claude-sonnet-4-6,anthropic.claude-opus-4-6-v1,anthropic.claude-3-5-sonnet-20240620-v1:0,meta.llama3-1-8b-instruct-v1:0
+# Cross-region inference model IDs: us.anthropic.claude-sonnet-4-6,us.anthropic.claude-opus-4-6-v1,global.anthropic.claude-opus-4-6-v1
 
 # See all Bedrock model IDs here: https://docs.aws.amazon.com/bedrock/latest/userguide/model-ids.html#model-ids-arns
 

api/models/tx.js

@@ -176,6 +176,7 @@ const tokenValues = Object.assign(
     'claude-opus-4-5': { prompt: 5, completion: 25 },
     'claude-opus-4-6': { prompt: 5, completion: 25 },
     'claude-sonnet-4': { prompt: 3, completion: 15 },
+    'claude-sonnet-4-6': { prompt: 3, completion: 15 },
     'command-r': { prompt: 0.5, completion: 1.5 },
     'command-r-plus': { prompt: 3, completion: 15 },
     'command-text': { prompt: 1.5, completion: 2.0 },
@@ -309,6 +310,7 @@ const cacheTokenValues = {
   'claude-3-haiku': { write: 0.3, read: 0.03 },
   'claude-haiku-4-5': { write: 1.25, read: 0.1 },
   'claude-sonnet-4': { write: 3.75, read: 0.3 },
+  'claude-sonnet-4-6': { write: 3.75, read: 0.3 },
   'claude-opus-4': { write: 18.75, read: 1.5 },
   'claude-opus-4-5': { write: 6.25, read: 0.5 },
   'claude-opus-4-6': { write: 6.25, read: 0.5 },
@@ -337,6 +339,7 @@ const cacheTokenValues = {
  */
 const premiumTokenValues = {
   'claude-opus-4-6': { threshold: 200000, prompt: 10, completion: 37.5 },
+  'claude-sonnet-4-6': { threshold: 200000, prompt: 6, completion: 22.5 },
 };
 
 /**

api/utils/tokens.spec.js

@@ -1162,6 +1162,56 @@ describe('Claude Model Tests', () => {
       expect(matchModelName(model, EModelEndpoint.anthropic)).toBe('claude-opus-4-6');
     });
   });
+
+  it('should return correct context length for Claude Sonnet 4.6 (1M)', () => {
+    expect(getModelMaxTokens('claude-sonnet-4-6', EModelEndpoint.anthropic)).toBe(
+      maxTokensMap[EModelEndpoint.anthropic]['claude-sonnet-4-6'],
+    );
+    expect(getModelMaxTokens('claude-sonnet-4-6')).toBe(
+      maxTokensMap[EModelEndpoint.anthropic]['claude-sonnet-4-6'],
+    );
+  });
+
+  it('should return correct max output tokens for Claude Sonnet 4.6 (64K)', () => {
+    const { getModelMaxOutputTokens } = require('@librechat/api');
+    expect(getModelMaxOutputTokens('claude-sonnet-4-6', EModelEndpoint.anthropic)).toBe(
+      maxOutputTokensMap[EModelEndpoint.anthropic]['claude-sonnet-4-6'],
+    );
+  });
+
+  it('should handle Claude Sonnet 4.6 model name variations', () => {
+    const modelVariations = [
+      'claude-sonnet-4-6',
+      'claude-sonnet-4-6-20260101',
+      'claude-sonnet-4-6-latest',
+      'anthropic/claude-sonnet-4-6',
+      'claude-sonnet-4-6/anthropic',
+      'claude-sonnet-4-6-preview',
+    ];
+
+    modelVariations.forEach((model) => {
+      const modelKey = findMatchingPattern(model, maxTokensMap[EModelEndpoint.anthropic]);
+      expect(modelKey).toBe('claude-sonnet-4-6');
+      expect(getModelMaxTokens(model, EModelEndpoint.anthropic)).toBe(
+        maxTokensMap[EModelEndpoint.anthropic]['claude-sonnet-4-6'],
+      );
+    });
+  });
+
+  it('should match model names correctly for Claude Sonnet 4.6', () => {
+    const modelVariations = [
+      'claude-sonnet-4-6',
+      'claude-sonnet-4-6-20260101',
+      'claude-sonnet-4-6-latest',
+      'anthropic/claude-sonnet-4-6',
+      'claude-sonnet-4-6/anthropic',
+      'claude-sonnet-4-6-preview',
+    ];
+
+    modelVariations.forEach((model) => {
+      expect(matchModelName(model, EModelEndpoint.anthropic)).toBe('claude-sonnet-4-6');
+    });
+  });
 });
 
 describe('Moonshot/Kimi Model Tests', () => {

packages/api/src/endpoints/anthropic/helpers.ts

@@ -65,7 +65,7 @@ function getClaudeHeaders(
 
 /**
  * Configures reasoning-related options for Claude models.
- * Models supporting adaptive thinking (Opus 4.6+, Sonnet 5+) use effort control instead of manual budget_tokens.
+ * Models supporting adaptive thinking (Opus 4.6+, Sonnet 4.6+) use effort control instead of manual budget_tokens.
  */
 function configureReasoning(
   anthropicInput: AnthropicClientOptions & { max_tokens?: number },

packages/api/src/endpoints/anthropic/llm.spec.ts

@@ -121,6 +121,39 @@ describe('getLLMConfig', () => {
     });
   });
 
+  it('should add "context-1m" beta header for claude-sonnet-4-6 model', () => {
+    const modelOptions = {
+      model: 'claude-sonnet-4-6',
+      promptCache: true,
+    };
+    const result = getLLMConfig('test-key', { modelOptions });
+    const clientOptions = result.llmConfig.clientOptions;
+    expect(clientOptions?.defaultHeaders).toBeDefined();
+    expect(clientOptions?.defaultHeaders).toHaveProperty('anthropic-beta');
+    const defaultHeaders = clientOptions?.defaultHeaders as Record<string, string>;
+    expect(defaultHeaders['anthropic-beta']).toBe('context-1m-2025-08-07');
+    expect(result.llmConfig.promptCache).toBe(true);
+  });
+
+  it('should add "context-1m" beta header for claude-sonnet-4-6 model formats', () => {
+    const modelVariations = [
+      'claude-sonnet-4-6',
+      'claude-sonnet-4-6-20260101',
+      'anthropic/claude-sonnet-4-6',
+    ];
+
+    modelVariations.forEach((model) => {
+      const modelOptions = { model, promptCache: true };
+      const result = getLLMConfig('test-key', { modelOptions });
+      const clientOptions = result.llmConfig.clientOptions;
+      expect(clientOptions?.defaultHeaders).toBeDefined();
+      expect(clientOptions?.defaultHeaders).toHaveProperty('anthropic-beta');
+      const defaultHeaders = clientOptions?.defaultHeaders as Record<string, string>;
+      expect(defaultHeaders['anthropic-beta']).toBe('context-1m-2025-08-07');
+      expect(result.llmConfig.promptCache).toBe(true);
+    });
+  });
+
   it('should pass promptCache boolean for claude-opus-4-5 model (no beta header needed)', () => {
     const modelOptions = {
       model: 'claude-opus-4-5',
@@ -963,6 +996,51 @@ describe('getLLMConfig', () => {
         });
       });
 
+      it('should use adaptive thinking for Sonnet 4.6 instead of enabled + budget_tokens', () => {
+        const result = getLLMConfig('test-key', {
+          modelOptions: {
+            model: 'claude-sonnet-4-6',
+            thinking: true,
+            thinkingBudget: 10000,
+          },
+        });
+
+        expect((result.llmConfig.thinking as unknown as { type: string }).type).toBe('adaptive');
+        expect(result.llmConfig.thinking).not.toHaveProperty('budget_tokens');
+        expect(result.llmConfig.maxTokens).toBe(64000);
+      });
+
+      it('should set effort via output_config for Sonnet 4.6', () => {
+        const result = getLLMConfig('test-key', {
+          modelOptions: {
+            model: 'claude-sonnet-4-6',
+            thinking: true,
+            effort: AnthropicEffort.high,
+          },
+        });
+
+        expect((result.llmConfig.thinking as unknown as { type: string }).type).toBe('adaptive');
+        expect(result.llmConfig.invocationKwargs).toHaveProperty('output_config');
+        expect(result.llmConfig.invocationKwargs?.output_config).toEqual({
+          effort: AnthropicEffort.high,
+        });
+      });
+
+      it('should exclude topP/topK for Sonnet 4.6 with adaptive thinking', () => {
+        const result = getLLMConfig('test-key', {
+          modelOptions: {
+            model: 'claude-sonnet-4-6',
+            thinking: true,
+            topP: 0.9,
+            topK: 40,
+          },
+        });
+
+        expect((result.llmConfig.thinking as unknown as { type: string }).type).toBe('adaptive');
+        expect(result.llmConfig).not.toHaveProperty('topP');
+        expect(result.llmConfig).not.toHaveProperty('topK');
+      });
+
       it('should NOT set adaptive thinking or effort for non-adaptive models', () => {
         const nonAdaptiveModels = [
           'claude-opus-4-5',

packages/api/src/utils/tokens.ts

@@ -148,6 +148,7 @@ const anthropicModels = {
   'claude-3.5-sonnet-latest': 200000,
   'claude-haiku-4-5': 200000,
   'claude-sonnet-4': 1000000,
+  'claude-sonnet-4-6': 1000000,
   'claude-4': 200000,
   'claude-opus-4': 200000,
   'claude-opus-4-5': 200000,
@@ -401,6 +402,7 @@ const anthropicMaxOutputs = {
   'claude-3-opus': 4096,
   'claude-haiku-4-5': 64000,
   'claude-sonnet-4': 64000,
+  'claude-sonnet-4-6': 64000,
   'claude-opus-4': 32000,
   'claude-opus-4-5': 64000,
   'claude-opus-4-6': 128000,

packages/data-provider/specs/bedrock.spec.ts

@@ -46,6 +46,30 @@ describe('supportsAdaptiveThinking', () => {
     expect(supportsAdaptiveThinking('claude-opus-4-0')).toBe(false);
   });
 
+  test('should return true for claude-sonnet-4-6', () => {
+    expect(supportsAdaptiveThinking('claude-sonnet-4-6')).toBe(true);
+  });
+
+  test('should return true for claude-sonnet-4.6', () => {
+    expect(supportsAdaptiveThinking('claude-sonnet-4.6')).toBe(true);
+  });
+
+  test('should return true for claude-sonnet-4-7 (future)', () => {
+    expect(supportsAdaptiveThinking('claude-sonnet-4-7')).toBe(true);
+  });
+
+  test('should return true for anthropic.claude-sonnet-4-6 (Bedrock)', () => {
+    expect(supportsAdaptiveThinking('anthropic.claude-sonnet-4-6')).toBe(true);
+  });
+
+  test('should return true for us.anthropic.claude-sonnet-4-6 (cross-region Bedrock)', () => {
+    expect(supportsAdaptiveThinking('us.anthropic.claude-sonnet-4-6')).toBe(true);
+  });
+
+  test('should return true for claude-4-6-sonnet (alternate naming)', () => {
+    expect(supportsAdaptiveThinking('claude-4-6-sonnet')).toBe(true);
+  });
+
   test('should return false for claude-sonnet-4-5', () => {
     expect(supportsAdaptiveThinking('claude-sonnet-4-5')).toBe(false);
   });
@@ -104,6 +128,14 @@ describe('supportsContext1m', () => {
     expect(supportsContext1m('claude-sonnet-4-5')).toBe(true);
   });
 
+  test('should return true for claude-sonnet-4-6', () => {
+    expect(supportsContext1m('claude-sonnet-4-6')).toBe(true);
+  });
+
+  test('should return true for anthropic.claude-sonnet-4-6 (Bedrock)', () => {
+    expect(supportsContext1m('anthropic.claude-sonnet-4-6')).toBe(true);
+  });
+
   test('should return true for claude-sonnet-5 (future)', () => {
     expect(supportsContext1m('claude-sonnet-5')).toBe(true);
   });
@@ -237,14 +269,42 @@ describe('bedrockInputParser', () => {
       ]);
     });
 
-    test('should match anthropic.claude-4-7-sonnet model with 1M context header', () => {
+    test('should match anthropic.claude-sonnet-4-6 with adaptive thinking and 1M context header', () => {
+      const input = {
+        model: 'anthropic.claude-sonnet-4-6',
+      };
+      const result = bedrockInputParser.parse(input) as Record<string, unknown>;
+      const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
+      expect(additionalFields.thinking).toEqual({ type: 'adaptive' });
+      expect(additionalFields.thinkingBudget).toBeUndefined();
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
+    });
+
+    test('should match us.anthropic.claude-sonnet-4-6 with adaptive thinking and 1M context header', () => {
+      const input = {
+        model: 'us.anthropic.claude-sonnet-4-6',
+      };
+      const result = bedrockInputParser.parse(input) as Record<string, unknown>;
+      const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
+      expect(additionalFields.thinking).toEqual({ type: 'adaptive' });
+      expect(additionalFields.thinkingBudget).toBeUndefined();
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
+    });
+
+    test('should match anthropic.claude-4-7-sonnet model with adaptive thinking and 1M context header', () => {
       const input = {
         model: 'anthropic.claude-4-7-sonnet',
       };
       const result = bedrockInputParser.parse(input) as Record<string, unknown>;
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
-      expect(additionalFields.thinking).toBe(true);
-      expect(additionalFields.thinkingBudget).toBe(2000);
+      expect(additionalFields.thinking).toEqual({ type: 'adaptive' });
+      expect(additionalFields.thinkingBudget).toBeUndefined();
       expect(additionalFields.anthropic_beta).toEqual([
         'output-128k-2025-02-19',
         'context-1m-2025-08-07',

packages/data-provider/src/bedrock.ts

@@ -35,27 +35,34 @@ function parseOpusVersion(model: string): { major: number; minor: number } | nul
   return null;
 }
 
-/** Extracts sonnet major version from both naming formats */
-function parseSonnetVersion(model: string): number | null {
-  const nameFirst = model.match(/claude-sonnet[-.]?(\d+)/);
+/** Extracts sonnet major/minor version from both naming formats.
+ *  Uses single-digit minor capture to avoid matching date suffixes (e.g., -20250514). */
+function parseSonnetVersion(model: string): { major: number; minor: number } | null {
+  const nameFirst = model.match(/claude-sonnet[-.]?(\d+)(?:[-.](\d)(?!\d))?/);
   if (nameFirst) {
-    return parseInt(nameFirst[1], 10);
+    return {
+      major: parseInt(nameFirst[1], 10),
+      minor: nameFirst[2] != null ? parseInt(nameFirst[2], 10) : 0,
+    };
   }
-  const numFirst = model.match(/claude-(\d+)(?:[-.]?\d+)?-sonnet/);
+  const numFirst = model.match(/claude-(\d+)(?:[-.](\d)(?!\d))?-sonnet/);
   if (numFirst) {
-    return parseInt(numFirst[1], 10);
+    return {
+      major: parseInt(numFirst[1], 10),
+      minor: numFirst[2] != null ? parseInt(numFirst[2], 10) : 0,
+    };
   }
   return null;
 }
 
-/** Checks if a model supports adaptive thinking (Opus 4.6+, Sonnet 5+) */
+/** Checks if a model supports adaptive thinking (Opus 4.6+, Sonnet 4.6+) */
 export function supportsAdaptiveThinking(model: string): boolean {
   const opus = parseOpusVersion(model);
   if (opus && (opus.major > 4 || (opus.major === 4 && opus.minor >= 6))) {
     return true;
   }
   const sonnet = parseSonnetVersion(model);
-  if (sonnet != null && sonnet >= 5) {
+  if (sonnet != null && (sonnet.major > 4 || (sonnet.major === 4 && sonnet.minor >= 6))) {
     return true;
   }
   return false;
@@ -64,7 +71,7 @@ export function supportsAdaptiveThinking(model: string): boolean {
 /** Checks if a model qualifies for the context-1m beta header (Sonnet 4+, Opus 4.6+, Opus 5+) */
 export function supportsContext1m(model: string): boolean {
   const sonnet = parseSonnetVersion(model);
-  if (sonnet != null && sonnet >= 4) {
+  if (sonnet != null && sonnet.major >= 4) {
     return true;
   }
   const opus = parseOpusVersion(model);

packages/data-provider/src/config.ts

@@ -1133,6 +1133,7 @@ const sharedOpenAIModels = [
 ];
 
 const sharedAnthropicModels = [
+  'claude-sonnet-4-6',
   'claude-opus-4-6',
   'claude-sonnet-4-5',
   'claude-sonnet-4-5-20250929',
@@ -1154,6 +1155,7 @@ const sharedAnthropicModels = [
 ];
 
 export const bedrockModels = [
+  'anthropic.claude-sonnet-4-6',
   'anthropic.claude-opus-4-6-v1',
   'anthropic.claude-sonnet-4-5-20250929-v1:0',
   'anthropic.claude-haiku-4-5-20251001-v1:0',