feat(zen): enable 1M context window for Opus 4.6 and Sonnet 4.5

packages/console/app/src/routes/zen/util/provider/anthropic.test.ts

@@ -0,0 +1,88 @@
+import { describe, it, expect } from "bun:test"
+import { supports1MContext } from "./anthropic"
+
+describe("supports1MContext", () => {
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return true for Opus 4.6 models
+
+  it("returns true for claude-opus-4-6", () => {
+    expect(supports1MContext("claude-opus-4-6")).toBe(true)
+  })
+
+  it("returns true for claude-opus-4-6 with snapshot date suffix", () => {
+    expect(supports1MContext("claude-opus-4-6-20260101")).toBe(true)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return true for Sonnet 4.5 models
+
+  it("returns true for claude-sonnet-4-5", () => {
+    expect(supports1MContext("claude-sonnet-4-5")).toBe(true)
+  })
+
+  it("returns true for claude-sonnet-4-5 with snapshot date suffix", () => {
+    expect(supports1MContext("claude-sonnet-4-5-20250929")).toBe(true)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return true for Sonnet 4 models (prefix match)
+
+  it("returns true for claude-sonnet-4 (canonical)", () => {
+    expect(supports1MContext("claude-sonnet-4")).toBe(true)
+  })
+
+  it("returns true for claude-sonnet-4-20250514", () => {
+    expect(supports1MContext("claude-sonnet-4-20250514")).toBe(true)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return false for Opus 4.5 models (not supported)
+
+  it("returns false for claude-opus-4-5-20251101", () => {
+    expect(supports1MContext("claude-opus-4-5-20251101")).toBe(false)
+  })
+
+  it("returns false for claude-opus-4-5", () => {
+    expect(supports1MContext("claude-opus-4-5")).toBe(false)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return false for older Opus models
+
+  it("returns false for claude-opus-4-1-20250805", () => {
+    expect(supports1MContext("claude-opus-4-1-20250805")).toBe(false)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return false for Haiku models
+
+  it("returns false for claude-haiku-4-5-20251001", () => {
+    expect(supports1MContext("claude-haiku-4-5-20251001")).toBe(false)
+  })
+
+  it("returns false for claude-3-haiku-20240307", () => {
+    expect(supports1MContext("claude-3-haiku-20240307")).toBe(false)
+  })
+
+  //#given a model string
+  //#when checking if it supports 1M context
+  //#then return false for unknown models
+
+  it("returns false for unknown model", () => {
+    expect(supports1MContext("some-random-model")).toBe(false)
+  })
+
+  //#given an empty string
+  //#when checking if it supports 1M context
+  //#then return false
+
+  it("returns false for empty string", () => {
+    expect(supports1MContext("")).toBe(false)
+  })
+})

packages/console/app/src/routes/zen/util/provider/anthropic.ts

@@ -16,11 +16,17 @@ type Usage = {
   }
 }
 
+const CONTEXT_1M_BETA = "context-1m-2025-08-07"
+
+export function supports1MContext(model: string): boolean {
+  const prefixes = ["claude-opus-4-6", "claude-sonnet-4-5", "claude-sonnet-4"]
+  return prefixes.some((prefix) => model.startsWith(prefix))
+}
+
 export const anthropicHelper: ProviderHelper = ({ reqModel, providerModel }) => {
   const isBedrockModelArn = providerModel.startsWith("arn:aws:bedrock:")
   const isBedrockModelID = providerModel.startsWith("global.anthropic.")
   const isBedrock = isBedrockModelArn || isBedrockModelID
-  const isSonnet = reqModel.includes("sonnet")
   return {
     format: "anthropic",
     modifyUrl: (providerApi: string, isStream?: boolean) =>
@@ -33,8 +39,8 @@ export const anthropicHelper: ProviderHelper = ({ reqModel, providerModel }) =>
       } else {
         headers.set("x-api-key", apiKey)
         headers.set("anthropic-version", headers.get("anthropic-version") ?? "2023-06-01")
-        if (body.model.startsWith("claude-sonnet-")) {
-          headers.set("anthropic-beta", "context-1m-2025-08-07")
+        if (supports1MContext(body.model)) {
+          headers.set("anthropic-beta", CONTEXT_1M_BETA)
         }
       }
     },
@@ -43,7 +49,7 @@ export const anthropicHelper: ProviderHelper = ({ reqModel, providerModel }) =>
       ...(isBedrock
         ? {
             anthropic_version: "bedrock-2023-05-31",
-            anthropic_beta: isSonnet ? "context-1m-2025-08-07" : undefined,
+            anthropic_beta: supports1MContext(reqModel) ? CONTEXT_1M_BETA : undefined,
             model: undefined,
             stream: undefined,
           }