feat: add beta support for Claude Sonnet 4 1M context window

- Default context window remains at 200K tokens
- Added UI checkbox to enable 1M context via beta flag 'context-1m-2025-08-07'
- Implemented tiered pricing structure that updates dynamically in model info
- Added context window display to ModelInfoView
- When beta is enabled:
  - Context window: 1,000,000 tokens
  - Input price: /MTok (vs standard /MTok)
  - Output price: 2.50/MTok (vs standard 5/MTok)
- Added anthropicBeta1MContext field to provider settings
- Updated AnthropicHandler to apply beta flag and adjust model info
- Updated useSelectedModel hook to apply tier pricing in UI when beta is enabled

Author: daniel-lxs

packages/types/src/provider-settings.ts

@@ -99,6 +99,7 @@ const anthropicSchema = apiModelIdProviderModelSchema.extend({
 	apiKey: z.string().optional(),
 	anthropicBaseUrl: z.string().optional(),
 	anthropicUseAuthToken: z.boolean().optional(),
+	anthropicBeta1MContext: z.boolean().optional(), // Enable 'context-1m-2025-08-07' beta for 1M context window
 })
 
 const claudeCodeSchema = apiModelIdProviderModelSchema.extend({

packages/types/src/providers/anthropic.ts

@@ -8,15 +8,25 @@ export const anthropicDefaultModelId: AnthropicModelId = "claude-sonnet-4-202505
 export const anthropicModels = {
 	"claude-sonnet-4-20250514": {
 		maxTokens: 64_000, // Overridden to 8k if `enableReasoningEffort` is false.
-		contextWindow: 1_000_000,
+		contextWindow: 200_000, // Default 200K, extendable to 1M with beta flag 'context-1m-2025-08-07'
 		supportsImages: true,
 		supportsComputerUse: true,
 		supportsPromptCache: true,
-		inputPrice: 3.0, // $3 per million input tokens
-		outputPrice: 15.0, // $15 per million output tokens
+		inputPrice: 3.0, // $3 per million input tokens (≤200K context)
+		outputPrice: 15.0, // $15 per million output tokens (≤200K context)
 		cacheWritesPrice: 3.75, // $3.75 per million tokens
 		cacheReadsPrice: 0.3, // $0.30 per million tokens
 		supportsReasoningBudget: true,
+		// Tiered pricing for extended context (requires beta flag 'context-1m-2025-08-07')
+		tiers: [
+			{
+				contextWindow: 1_000_000, // 1M tokens with beta flag
+				inputPrice: 6.0, // $6 per million input tokens (>200K context)
+				outputPrice: 22.5, // $22.50 per million output tokens (>200K context)
+				cacheWritesPrice: 3.75, // Same cache pricing
+				cacheReadsPrice: 0.3,
+			},
+		],
 	},
 	"claude-opus-4-1-20250805": {
 		maxTokens: 8192,

src/api/providers/anthropic.ts

@@ -45,6 +45,11 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 		const cacheControl: CacheControlEphemeral = { type: "ephemeral" }
 		let { id: modelId, betas = [], maxTokens, temperature, reasoning: thinking } = this.getModel()
 
+		// Add 1M context beta flag if enabled for Claude Sonnet 4
+		if (modelId === "claude-sonnet-4-20250514" && this.options.anthropicBeta1MContext) {
+			betas.push("context-1m-2025-08-07")
+		}
+
 		switch (modelId) {
 			case "claude-sonnet-4-20250514":
 			case "claude-opus-4-1-20250805":
@@ -236,7 +241,21 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 	getModel() {
 		const modelId = this.options.apiModelId
 		let id = modelId && modelId in anthropicModels ? (modelId as AnthropicModelId) : anthropicDefaultModelId
-		const info: ModelInfo = anthropicModels[id]
+		let info: ModelInfo = anthropicModels[id]
+
+		// If 1M context beta is enabled for Claude Sonnet 4, update the model info
+		if (id === "claude-sonnet-4-20250514" && this.options.anthropicBeta1MContext) {
+			// Use the tier pricing for 1M context
+			const tier = info.tiers?.[0]
+			if (tier) {
+				info = {
+					...info,
+					contextWindow: tier.contextWindow,
+					inputPrice: tier.inputPrice,
+					outputPrice: tier.outputPrice,
+				}
+			}
+		}
 
 		const params = getModelParams({
 			format: "anthropic",

webview-ui/src/components/settings/ModelInfoView.tsx

@@ -41,6 +41,11 @@ export const ModelInfoView = ({
 			supportsLabel={t("settings:modelInfo.supportsPromptCache")}
 			doesNotSupportLabel={t("settings:modelInfo.noPromptCache")}
 		/>,
+		typeof modelInfo?.contextWindow === "number" && modelInfo.contextWindow > 0 && (
+			<>
+				<span className="font-medium">Context Window:</span> {modelInfo.contextWindow?.toLocaleString()} tokens
+			</>
+		),
 		typeof modelInfo?.maxTokens === "number" && modelInfo.maxTokens > 0 && (
 			<>
 				<span className="font-medium">{t("settings:modelInfo.maxOutput")}:</span>{" "}

webview-ui/src/components/settings/providers/Anthropic.tsx

@@ -6,6 +6,7 @@ import type { ProviderSettings } from "@roo-code/types"
 
 import { useAppTranslation } from "@src/i18n/TranslationContext"
 import { VSCodeButtonLink } from "@src/components/common/VSCodeButtonLink"
+import { useSelectedModel } from "@src/components/ui/hooks/useSelectedModel"
 
 import { inputEventTransform, noTransform } from "../transforms"
 
@@ -16,9 +17,13 @@ type AnthropicProps = {
 
 export const Anthropic = ({ apiConfiguration, setApiConfigurationField }: AnthropicProps) => {
 	const { t } = useAppTranslation()
+	const selectedModel = useSelectedModel(apiConfiguration)
 
 	const [anthropicBaseUrlSelected, setAnthropicBaseUrlSelected] = useState(!!apiConfiguration?.anthropicBaseUrl)
 
+	// Check if the current model supports 1M context beta
+	const supports1MContextBeta = selectedModel?.id === "claude-sonnet-4-20250514"
+
 	const handleInputChange = useCallback(
 		<K extends keyof ProviderSettings, E>(
 			field: K,
@@ -79,6 +84,20 @@ export const Anthropic = ({ apiConfiguration, setApiConfigurationField }: Anthro
 					</>
 				)}
 			</div>
+			{supports1MContextBeta && (
+				<div>
+					<Checkbox
+						checked={apiConfiguration?.anthropicBeta1MContext ?? false}
+						onChange={(checked: boolean) => {
+							setApiConfigurationField("anthropicBeta1MContext", checked)
+						}}>
+						Enable 1M context window (Beta)
+					</Checkbox>
+					<div className="text-sm text-vscode-descriptionForeground mt-1 ml-6">
+						Extends context window to 1 million tokens for Claude Sonnet 4
+					</div>
+				</div>
+			)}
 		</>
 	)
 }

webview-ui/src/components/ui/hooks/useSelectedModel.ts

@@ -291,8 +291,33 @@ function getSelectedModel({
 		default: {
 			provider satisfies "anthropic" | "gemini-cli" | "human-relay" | "fake-ai"
 			const id = apiConfiguration.apiModelId ?? anthropicDefaultModelId
-			const info = anthropicModels[id as keyof typeof anthropicModels]
-			return { id, info }
+			const baseInfo = anthropicModels[id as keyof typeof anthropicModels]
+
+			// Apply 1M context beta tier pricing for Claude Sonnet 4
+			if (
+				provider === "anthropic" &&
+				id === "claude-sonnet-4-20250514" &&
+				apiConfiguration.anthropicBeta1MContext &&
+				baseInfo
+			) {
+				// Type assertion since we know claude-sonnet-4-20250514 has tiers
+				const modelWithTiers = baseInfo as typeof baseInfo & {
+					tiers?: Array<{ contextWindow: number; inputPrice?: number; outputPrice?: number }>
+				}
+				const tier = modelWithTiers.tiers?.[0]
+				if (tier) {
+					// Create a new ModelInfo object with updated values
+					const info: ModelInfo = {
+						...baseInfo,
+						contextWindow: tier.contextWindow,
+						inputPrice: tier.inputPrice ?? baseInfo.inputPrice,
+						outputPrice: tier.outputPrice ?? baseInfo.outputPrice,
+					}
+					return { id, info }
+				}
+			}
+
+			return { id, info: baseInfo }
 		}
 	}
 }