🤖 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.

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,