feat: [ENG-3652] 1M Context window for Sonnet 4, 4.5 (#5308)

* use 1m header on all anthropic providers

* tests and changelog

* changelog

Author: connortbot

bifrost/app/changelog/changes/20251126-sonnet-4-1m-context/metadata.json

@@ -0,0 +1,4 @@
+{
+  "title": "Claude Sonnet 4 and Sonnet 4.5 now support 1M context window",
+  "description": "Updated AI Gateway to enable 1M context window by default for Claude Sonnet 4 and Claude Sonnet 4.5 models across all providers."
+}

bifrost/app/changelog/changes/20251126-sonnet-4-1m-context/src.mdx

@@ -0,0 +1,8 @@
+Claude Sonnet 4 and Claude Sonnet 4.5 models on the AI Gateway now support 1M context window by default.
+
+## What's Changed
+
+- **1M Context Window**: Sonnet 4 and Sonnet 4.5 models now use the extended 1M token context window by default
+- **All Providers**: This update applies to Anthropic API, AWS Bedrock, and Google Vertex AI
+
+No configuration changes are needed - requests to Sonnet 4 models will automatically use the extended context window.

packages/__tests__/cost/__snapshots__/registrySnapshots.test.ts.snap

@@ -1347,7 +1347,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
   },
   "anthropic/claude-sonnet-4": {
     "claude-sonnet-4:anthropic": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": false,
       "maxTokens": 64000,
       "modelId": "claude-sonnet-4-20250514",
@@ -1367,7 +1367,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4:bedrock": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": true,
       "maxTokens": 64000,
       "modelId": "anthropic.claude-sonnet-4-20250514-v1:0",
@@ -1389,7 +1389,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4:helicone": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": false,
       "maxTokens": 64000,
       "modelId": "pa/cd-st-4-20250514",
@@ -1429,7 +1429,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4:vertex": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": true,
       "maxTokens": 64000,
       "modelId": "claude-sonnet-4@20250514",
@@ -1451,7 +1451,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
   },
   "anthropic/claude-sonnet-4-5-20250929": {
     "claude-sonnet-4-5-20250929:anthropic": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": false,
       "maxTokens": 64000,
       "modelId": "claude-sonnet-4-5-20250929",
@@ -1471,7 +1471,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4-5-20250929:bedrock": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": true,
       "maxTokens": 64000,
       "modelId": "anthropic.claude-sonnet-4-5-20250929-v1:0",
@@ -1493,7 +1493,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4-5-20250929:helicone": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": false,
       "maxTokens": 64000,
       "modelId": "pa/claude-sonnet-4-5-20250929",
@@ -1513,7 +1513,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4-5-20250929:openrouter": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": false,
       "maxTokens": 64000,
       "modelId": "anthropic/claude-sonnet-4.5",
@@ -1533,7 +1533,7 @@ exports[`Registry Snapshots endpoint configurations snapshot 1`] = `
       ],
     },
     "claude-sonnet-4-5-20250929:vertex": {
-      "context": 200000,
+      "context": 1000000,
       "crossRegion": true,
       "maxTokens": 64000,
       "modelId": "claude-sonnet-4-5@20250929",
@@ -6378,6 +6378,11 @@ exports[`Registry Snapshots pricing snapshot 1`] = `
         "threshold": 0,
         "web_search": 0.01,
       },
+      {
+        "input": 0.00000633,
+        "output": 0.0000237375,
+        "threshold": 200000,
+      },
     ],
     "vertex": [
       {
@@ -6454,6 +6459,11 @@ exports[`Registry Snapshots pricing snapshot 1`] = `
         "output": 0.00002374,
         "threshold": 0,
       },
+      {
+        "input": 0.00000633,
+        "output": 0.0000237375,
+        "threshold": 200000,
+      },
     ],
     "vertex": [
       {

packages/__tests__/cost/providers/anthropic.test.ts

@@ -0,0 +1,70 @@
+import { AnthropicProvider } from "../../../cost/models/providers/anthropic";
+
+describe("AnthropicProvider", () => {
+  const provider = new AnthropicProvider();
+
+  describe("buildUrl", () => {
+    it("should return the Anthropic messages endpoint", () => {
+      const url = provider.buildUrl(
+        { providerModelId: "claude-3-haiku" } as any,
+        { isStreaming: false }
+      );
+
+      expect(url).toBe("https://api.anthropic.com/v1/messages");
+    });
+  });
+
+  describe("authenticate", () => {
+    it("should return x-api-key header with provided key", () => {
+      const result = provider.authenticate(
+        { apiKey: "test-api-key" },
+        { providerModelId: "claude-3-haiku" } as any
+      );
+
+      expect(result.headers["x-api-key"]).toBe("test-api-key");
+    });
+
+    it("should return anthropic-version header", () => {
+      const result = provider.authenticate(
+        { apiKey: "test-api-key", bodyMapping: "OPENAI" },
+        { providerModelId: "claude-3-haiku" } as any
+      );
+
+      expect(result.headers["anthropic-version"]).toBe("2023-06-01");
+    });
+
+    it("should include anthropic-beta header for sonnet-4 models", () => {
+      const result = provider.authenticate(
+        { apiKey: "test-api-key" },
+        { providerModelId: "claude-sonnet-4-20250514" } as any
+      );
+
+      expect(result.headers["x-api-key"]).toBe("test-api-key");
+      expect(result.headers["anthropic-beta"]).toBe("context-1m-2025-08-07");
+    });
+
+    it("should not include anthropic-beta header for non-sonnet-4 models", () => {
+      const result = provider.authenticate(
+        { apiKey: "test-api-key" },
+        { providerModelId: "claude-3-5-sonnet-20241022" } as any
+      );
+
+      expect(result.headers["x-api-key"]).toBe("test-api-key");
+      expect(result.headers["anthropic-beta"]).toBeUndefined();
+    });
+  });
+
+  describe("provider metadata", () => {
+    it("should have correct display name", () => {
+      expect(provider.displayName).toBe("Anthropic");
+    });
+
+    it("should have correct auth type", () => {
+      expect(provider.auth).toBe("api-key");
+    });
+
+    it("should have correct base URL", () => {
+      expect(provider.baseUrl).toBe("https://api.anthropic.com");
+    });
+  });
+});

packages/__tests__/cost/providers/bedrock.test.ts

@@ -0,0 +1,161 @@
+import { BedrockProvider } from "../../../cost/models/providers/bedrock";
+
+describe("BedrockProvider", () => {
+  const provider = new BedrockProvider();
+
+  describe("buildUrl", () => {
+    it("should build invoke URL for non-streaming requests", () => {
+      const url = provider.buildUrl(
+        {
+          providerModelId: "anthropic.claude-3-haiku-20240307-v1:0",
+          modelConfig: { providerModelId: "anthropic.claude-3-haiku-20240307-v1:0" },
+          userConfig: { region: "us-east-1" },
+        } as any,
+        { isStreaming: false }
+      );
+
+      expect(url).toBe(
+        "https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-3-haiku-20240307-v1:0/invoke"
+      );
+    });
+
+    it("should build invoke-with-response-stream URL for streaming requests", () => {
+      const url = provider.buildUrl(
+        {
+          providerModelId: "anthropic.claude-3-haiku-20240307-v1:0",
+          modelConfig: { providerModelId: "anthropic.claude-3-haiku-20240307-v1:0" },
+          userConfig: { region: "us-west-2" },
+        } as any,
+        { isStreaming: true }
+      );
+
+      expect(url).toBe(
+        "https://bedrock-runtime.us-west-2.amazonaws.com/model/anthropic.claude-3-haiku-20240307-v1:0/invoke-with-response-stream"
+      );
+    });
+
+    it("should add region prefix for cross-region requests", () => {
+      const url = provider.buildUrl(
+        {
+          providerModelId: "anthropic.claude-3-haiku-20240307-v1:0",
+          modelConfig: { providerModelId: "anthropic.claude-3-haiku-20240307-v1:0" },
+          userConfig: { region: "us-east-1", crossRegion: true },
+        } as any,
+        { isStreaming: false }
+      );
+
+      expect(url).toBe(
+        "https://bedrock-runtime.us-east-1.amazonaws.com/model/us.anthropic.claude-3-haiku-20240307-v1:0/invoke"
+      );
+    });
+
+    it("should default to us-east-1 region when not specified", () => {
+      const url = provider.buildUrl(
+        {
+          providerModelId: "anthropic.claude-3-haiku-20240307-v1:0",
+          modelConfig: { providerModelId: "anthropic.claude-3-haiku-20240307-v1:0" },
+          userConfig: {},
+        } as any,
+        { isStreaming: false }
+      );
+
+      expect(url).toBe(
+        "https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-3-haiku-20240307-v1:0/invoke"
+      );
+    });
+  });
+
+  describe("authenticate", () => {
+    it("should throw error when apiKey is missing", async () => {
+      await expect(
+        provider.authenticate(
+          { secretKey: "test-secret-key" },
+          { providerModelId: "claude-3-haiku", userConfig: { region: "us-east-1" } } as any
+        )
+      ).rejects.toThrow("Bedrock requires both apiKey and secretKey");
+    });
+
+    it("should throw error when secretKey is missing", async () => {
+      await expect(
+        provider.authenticate(
+          { apiKey: "test-access-key" },
+          { providerModelId: "claude-3-haiku", userConfig: { region: "us-east-1" } } as any
+        )
+      ).rejects.toThrow("Bedrock requires both apiKey and secretKey");
+    });
+
+    it("should throw error when requestMethod is missing", async () => {
+      await expect(
+        provider.authenticate(
+          {
+            apiKey: "test-access-key",
+            secretKey: "test-secret-key",
+            requestUrl: "https://test.com",
+            requestBody: "{}"
+          },
+          { providerModelId: "claude-3-haiku", userConfig: { region: "us-east-1" } } as any
+        )
+      ).rejects.toThrow("Bedrock authentication requires requestMethod, requestUrl, and requestBody");
+    });
+  });
+
+  describe("buildRequestBody", () => {
+    it("should add anthropic_version for Claude models with OPENAI mapping", () => {
+      const body = provider.buildRequestBody(
+        { providerModelId: "anthropic.claude-3-haiku-20240307-v1:0" } as any,
+        {
+          bodyMapping: "OPENAI",
+          toAnthropic: (body: any) => ({ ...body, converted: true }),
+          parsedBody: {
+            model: "claude-3-haiku",
+            messages: [{ role: "user", content: "Test" }]
+          }
+        } as any
+      );
+
+      const parsed = JSON.parse(body);
+      expect(parsed.anthropic_version).toBe("bedrock-2023-05-31");
+      expect(parsed.converted).toBe(true);
+      expect(parsed.model).toBeUndefined();
+      expect(parsed.stream).toBeUndefined();
+    });
+
+    it("should handle Claude models without OPENAI mapping", () => {
+      const body = provider.buildRequestBody(
+        { providerModelId: "anthropic.claude-3-5-sonnet-20241022-v1:0" } as any,
+        {
+          bodyMapping: "NO_MAPPING",
+          parsedBody: {
+            messages: [{ role: "user", content: "Hello" }],
+            max_tokens: 1024
+          }
+        } as any
+      );
+
+      const parsed = JSON.parse(body);
+      expect(parsed.anthropic_version).toBe("bedrock-2023-05-31");
+      expect(parsed.messages).toEqual([{ role: "user", content: "Hello" }]);
+      expect(parsed.max_tokens).toBe(1024);
+      expect(parsed.model).toBeUndefined();
+      expect(parsed.stream).toBeUndefined();
+    });
+  });
+
+  describe("provider metadata", () => {
+    it("should have correct display name", () => {
+      expect(provider.displayName).toBe("AWS Bedrock");
+    });
+
+    it("should have correct auth type", () => {
+      expect(provider.auth).toBe("aws-signature");
+    });
+
+    it("should have correct required config", () => {
+      expect(provider.requiredConfig).toEqual(["region"]);
+    });
+
+    it("should have correct base URL template", () => {
+      expect(provider.baseUrl).toBe("https://bedrock-runtime.{region}.amazonaws.com");
+    });
+  });
+});

packages/__tests__/cost/providers/vertex.test.ts

@@ -298,7 +298,7 @@ describe("VertexProvider", () => {
     it("should return Bearer token with Google access token", async () => {
       const result = await provider.authenticate(
         { apiKey: '{"type":"service_account"}', orgId: "test-org" },
-        {} as any,
+        { providerModelId: "claude-3-haiku" } as any,
         undefined
       );
 
@@ -326,7 +326,7 @@ describe("VertexProvider", () => {
 
       await provider.authenticate(
         { apiKey: '{"type":"service_account"}', orgId: "test-org" },
-        {} as any,
+        { providerModelId: "claude-3-haiku" } as any,
         mockCacheProvider as any
       );
 
@@ -337,6 +337,28 @@ describe("VertexProvider", () => {
         mockCacheProvider
       );
     });
+
+    it("should include anthropic-beta header for sonnet-4 models", async () => {
+      const result = await provider.authenticate(
+        { apiKey: '{"type":"service_account"}', orgId: "test-org" },
+        { providerModelId: "claude-sonnet-4-20250514" } as any,
+        undefined
+      );
+
+      expect(result.headers.Authorization).toBe("Bearer test-access-token");
+      expect(result.headers["anthropic-beta"]).toBe("context-1m-2025-08-07");
+    });
+
+    it("should not include anthropic-beta header for non-sonnet-4 models", async () => {
+      const result = await provider.authenticate(
+        { apiKey: '{"type":"service_account"}', orgId: "test-org" },
+        { providerModelId: "claude-3-5-sonnet-20241022" } as any,
+        undefined
+      );
+
+      expect(result.headers.Authorization).toBe("Bearer test-access-token");
+      expect(result.headers["anthropic-beta"]).toBeUndefined();
+    });
   });
 
   describe("Edge cases", () => {