feat: Adding Max Context Window setting for Gemini API provider

packages/types/src/provider-settings.ts

@@ -152,6 +152,7 @@ const lmStudioSchema = baseProviderSettingsSchema.extend({
 const geminiSchema = apiModelIdProviderModelSchema.extend({
 	geminiApiKey: z.string().optional(),
 	googleGeminiBaseUrl: z.string().optional(),
+	maxContextWindow: z.number().nullish(),
 })
 
 const openAiNativeSchema = apiModelIdProviderModelSchema.extend({
@@ -318,6 +319,7 @@ export const PROVIDER_SETTINGS_KEYS = keysOf<ProviderSettings>()([
 	// Gemini
 	"geminiApiKey",
 	"googleGeminiBaseUrl",
+	"maxContextWindow",
 	// OpenAI Native
 	"openAiNativeApiKey",
 	"openAiNativeBaseUrl",

src/api/providers/gemini.ts

@@ -132,9 +132,16 @@ export class GeminiHandler extends BaseProvider implements SingleCompletionHandl
 	override getModel() {
 		const modelId = this.options.apiModelId
 		let id = modelId && modelId in geminiModels ? (modelId as GeminiModelId) : geminiDefaultModelId
-		const info: ModelInfo = geminiModels[id]
+		let info: ModelInfo = geminiModels[id]
 		const params = getModelParams({ format: "gemini", modelId: id, model: info, settings: this.options })
 
+		if (this.options.maxContextWindow) {
+			info = {
+				...info,
+				contextWindow: this.options.maxContextWindow,
+			}
+		}
+
 		// The `:thinking` suffix indicates that the model is a "Hybrid"
 		// reasoning model and that reasoning is required to be enabled.
 		// The actual model ID honored by Gemini's API does not have this

src/core/task/Task.ts

@@ -1667,7 +1667,10 @@ export class Task extends EventEmitter<ClineEvents> {
 				? this.apiConfiguration.modelMaxTokens || DEFAULT_THINKING_MODEL_MAX_TOKENS
 				: modelInfo.maxTokens
 
-			const contextWindow = modelInfo.contextWindow
+			const contextWindow =
+				this.apiConfiguration.apiProvider === "gemini" && this.apiConfiguration.maxContextWindow
+					? this.apiConfiguration.maxContextWindow
+					: modelInfo.contextWindow
 
 			const truncateResult = await truncateConversationIfNeeded({
 				messages: this.apiConversationHistory,

src/core/task/__tests__/Task.test.ts

@@ -14,6 +14,7 @@ import { ClineProvider } from "../../webview/ClineProvider"
 import { ApiStreamChunk } from "../../../api/transform/stream"
 import { ContextProxy } from "../../config/ContextProxy"
 import { processUserContentMentions } from "../../mentions/processUserContentMentions"
+import * as slidingWindow from "../../sliding-window"
 
 jest.mock("execa", () => ({
 	execa: jest.fn(),
@@ -533,6 +534,82 @@ describe("Cline", () => {
 				})
 			})
 
+			it("should use maxContextWindow when provider is gemini and maxContextWindow is set", async () => {
+				// Arrange: set apiProvider to gemini and maxContextWindow
+				const geminiConfig = {
+					...mockApiConfig,
+					apiProvider: "gemini" as const,
+					maxContextWindow: 42,
+				}
+				const created = Task.create({
+					provider: mockProvider,
+					apiConfiguration: geminiConfig,
+					task: "test gemini context window",
+				}) as unknown as [any, Promise<void>]
+				const cline = created[0] as any
+				const task = created[1] as Promise<void>
+
+				// Stub model info to have a different default contextWindow
+				;(cline.api as any).getModel = jest.fn().mockReturnValue({
+					id: "gemini-model",
+					info: {
+						contextWindow: 100,
+						supportsReasoningBudget: true,
+						maxTokens: 1000,
+						supportsComputerUse: false,
+						supportsPromptCache: false,
+						inputPrice: 0,
+						outputPrice: 0,
+					},
+				})
+
+				// Stub required methods to let attemptApiRequest proceed
+				;(cline as any).getSystemPrompt = jest.fn().mockResolvedValue("")
+				;(cline as any).getTokenUsage = jest.fn().mockReturnValue({
+					contextTokens: 1,
+					totalTokensIn: 0,
+					totalTokensOut: 0,
+					totalCost: 0,
+				})
+
+				// Stub createMessage to avoid real API calls
+				jest.spyOn(cline.api as any, "createMessage").mockReturnValue((async function* () {})())
+
+				// Spy on truncateConversationIfNeeded to capture its options
+				const twSpy = jest.spyOn(slidingWindow, "truncateConversationIfNeeded").mockResolvedValue({
+					messages: [],
+					summary: "",
+					cost: 0,
+					prevContextTokens: 0,
+					newContextTokens: 0,
+					error: undefined,
+				})
+
+				// Force abort immediately so the stream loop exits
+				Object.defineProperty(cline, "abort", {
+					get: () => false,
+					set: () => {},
+					configurable: true,
+				})
+
+				// Act: run through the generator
+				try {
+					for await (const _ of cline.attemptApiRequest()) {
+					}
+				} catch {
+					/* ignore */
+				}
+
+				// Assert: the contextWindow passed to truncateConversationIfNeeded is the maxContextWindow
+				expect(twSpy).toHaveBeenCalled()
+				const optionsPassed = twSpy.mock.calls[0][0]
+				expect(optionsPassed.contextWindow).toBe(42)
+
+				// Cleanup
+				await cline.abortTask(true)
+				await task.catch(() => {})
+			})
+
 			it.skip("should handle API retry with countdown", async () => {
 				const [cline, task] = Task.create({
 					provider: mockProvider,

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

@@ -51,6 +51,7 @@ import { ApiErrorMessage } from "./ApiErrorMessage"
 import { ThinkingBudget } from "./ThinkingBudget"
 import { DiffSettingsControl } from "./DiffSettingsControl"
 import { TemperatureControl } from "./TemperatureControl"
+import { MaxContextWindowControl } from "./MaxContextWindowControl"
 import { RateLimitSecondsControl } from "./RateLimitSecondsControl"
 import { BedrockCustomArn } from "./providers/BedrockCustomArn"
 import { buildDocLink } from "@src/utils/docLinks"
@@ -461,6 +462,7 @@ const ApiOptions = ({
 						modelInfo={selectedModelInfo}
 						isDescriptionExpanded={isDescriptionExpanded}
 						setIsDescriptionExpanded={setIsDescriptionExpanded}
+						maxContextWindow={selectedProvider === "gemini" ? apiConfiguration.maxContextWindow : undefined}
 					/>
 				</>
 			)}
@@ -484,6 +486,15 @@ const ApiOptions = ({
 						onChange={handleInputChange("modelTemperature", noTransform)}
 						maxValue={2}
 					/>
+
+					{selectedProvider === "gemini" && (
+						<MaxContextWindowControl
+							value={apiConfiguration.maxContextWindow}
+							onChange={handleInputChange("maxContextWindow", noTransform)}
+							maxValue={1048576}
+						/>
+					)}
+
 					<RateLimitSecondsControl
 						value={apiConfiguration.rateLimitSeconds || 0}
 						onChange={(value) => setApiConfigurationField("rateLimitSeconds", value)}

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

@@ -0,0 +1,71 @@
+import { VSCodeCheckbox } from "@vscode/webview-ui-toolkit/react"
+import { useEffect, useState } from "react"
+import { useAppTranslation } from "@/i18n/TranslationContext"
+import { useDebounce } from "react-use"
+
+import { Slider } from "@/components/ui"
+
+interface MaxContextWindowControlProps {
+	value: number | undefined | null
+	onChange: (value: number | undefined | null) => void
+	maxValue?: number
+}
+
+export const MaxContextWindowControl = ({ value, onChange, maxValue = 1000000 }: MaxContextWindowControlProps) => {
+	const { t } = useAppTranslation()
+	const [isCustomMaxContextWindow, setIsCustomMaxContextWindow] = useState(value !== undefined)
+	const [inputValue, setInputValue] = useState(value)
+
+	useDebounce(() => onChange(inputValue), 50, [onChange, inputValue])
+
+	// Sync internal state with prop changes when switching profiles.
+	useEffect(() => {
+		const hasCustomMaxContextWindow = value !== undefined && value !== null
+		setIsCustomMaxContextWindow(hasCustomMaxContextWindow)
+		setInputValue(value)
+	}, [value])
+
+	return (
+		<>
+			<div>
+				<VSCodeCheckbox
+					checked={isCustomMaxContextWindow}
+					onChange={(e: any) => {
+						const isChecked = e.target.checked
+						setIsCustomMaxContextWindow(isChecked)
+
+						if (!isChecked) {
+							setInputValue(null) // Unset the max context window limit, note that undefined is unserializable.
+						} else {
+							setInputValue(value ?? 0) // Use the value from apiConfiguration, if set.
+						}
+					}}>
+					<label className="block font-medium mb-1">{t("settings:maxContextWindow.useCustom")}</label>
+				</VSCodeCheckbox>
+				<div className="text-sm text-vscode-descriptionForeground mt-1">
+					{t("settings:maxContextWindow.description")}
+				</div>
+			</div>
+
+			{isCustomMaxContextWindow && (
+				<div className="flex flex-col gap-3 pl-3 border-l-2 border-vscode-button-background">
+					<div>
+						<div className="flex items-center gap-2">
+							<Slider
+								min={32000}
+								max={maxValue}
+								step={1}
+								value={[inputValue ?? 1048576]}
+								onValueChange={([value]) => setInputValue(value)}
+							/>
+							<span className="w-10">{inputValue}</span>
+						</div>
+						<div className="text-vscode-descriptionForeground text-sm mt-1">
+							{t("settings:maxContextWindow.rangeDescription")}
+						</div>
+					</div>
+				</div>
+			)}
+		</>
+	)
+}

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

@@ -14,6 +14,7 @@ type ModelInfoViewProps = {
 	modelInfo?: ModelInfo
 	isDescriptionExpanded: boolean
 	setIsDescriptionExpanded: (isExpanded: boolean) => void
+	maxContextWindow?: number | null
 }
 
 export const ModelInfoView = ({
@@ -22,9 +23,13 @@ export const ModelInfoView = ({
 	modelInfo,
 	isDescriptionExpanded,
 	setIsDescriptionExpanded,
+	maxContextWindow,
 }: ModelInfoViewProps) => {
 	const { t } = useAppTranslation()
 
+	const maxContextWindowValue =
+		apiProvider === "gemini" && maxContextWindow ? maxContextWindow : modelInfo?.contextWindow
+
 	const infoItems = [
 		<ModelInfoSupportsItem
 			isSupported={modelInfo?.supportsImages ?? false}
@@ -71,6 +76,15 @@ export const ModelInfoView = ({
 				{formatPrice(modelInfo.cacheWritesPrice || 0)} / 1M tokens
 			</>
 		),
+		maxContextWindowValue && (
+			<>
+				<span className="font-medium">{t("settings:maxContextWindow.maxContextWindow")}:</span>{" "}
+				{maxContextWindowValue.toLocaleString()} tokens
+				{apiProvider === "gemini" && maxContextWindowValue && (
+					<span className="text-vscode-descriptionForeground ml-1">(custom limit)</span>
+				)}
+			</>
+		),
 		apiProvider === "gemini" && (
 			<span className="italic">
 				{selectedModelId.includes("pro-preview")

webview-ui/src/components/settings/__tests__/MaxContextWindowControl.test.tsx

@@ -0,0 +1,57 @@
+import { render, screen, fireEvent } from "@testing-library/react"
+import { MaxContextWindowControl } from "../MaxContextWindowControl"
+import "@testing-library/jest-dom"
+
+class MockResizeObserver {
+	observe() {}
+	unobserve() {}
+	disconnect() {}
+}
+global.ResizeObserver = MockResizeObserver
+
+jest.mock("@/components/ui", () => ({
+	...jest.requireActual("@/components/ui"),
+	Slider: ({ value, onValueChange, min = 0, max = 100, "data-testid": dataTestId }: any) => (
+		<input
+			type="range"
+			min={min}
+			max={max}
+			value={value[0]}
+			onChange={(e) => onValueChange([parseInt(e.target.value, 10)])}
+			data-testid={dataTestId}
+		/>
+	),
+}))
+
+describe("MaxContextWindowControl", () => {
+	it("updates when checkbox is toggled", async () => {
+		const onChange = jest.fn()
+		render(<MaxContextWindowControl value={123} onChange={onChange} />)
+
+		const checkbox = screen.getByRole("checkbox") as HTMLInputElement
+		fireEvent.click(checkbox)
+
+		await new Promise((r) => setTimeout(r, 100))
+		expect(onChange).toHaveBeenCalledWith(null)
+
+		fireEvent.click(checkbox)
+
+		await new Promise((r) => setTimeout(r, 100))
+		expect(onChange).toHaveBeenCalledWith(123)
+	})
+
+	it("calls onChange when slider is moved", async () => {
+		const onChange = jest.fn()
+		render(<MaxContextWindowControl value={35000} onChange={onChange} />)
+
+		const checkbox = screen.getByRole("checkbox") as HTMLInputElement
+		expect(checkbox).toBeChecked()
+
+		const slider = screen.getByRole("slider")
+		fireEvent.change(slider, { target: { value: "50000" } })
+
+		await new Promise((r) => setTimeout(r, 120))
+
+		expect(onChange).toHaveBeenCalledWith(50000)
+	})
+})

webview-ui/src/i18n/locales/ca/settings.json

@@ -503,6 +503,12 @@
 		"description": "Controla l'aleatorietat en les respostes del model.",
 		"rangeDescription": "Valors més alts fan que la sortida sigui més aleatòria, valors més baixos la fan més determinista."
 	},
+	"maxContextWindow": {
+		"maxContextWindow": "",
+		"useCustom": "Utilitza una finestra de context màxim personalitzada",
+		"description": "Estableix la mida màxima de la finestra de context per al model. Quan les converses s'acosten a aquest límit, Roo Code condensarà automàticament els missatges més antics per mantenir-se dins de la restricció.",
+		"rangeDescription": "Els valors més alts permeten converses més llargues abans de condensar-se, els valors més baixos activen la condensació abans per mantenir-se dins dels límits de velocitat de l'API."
+	},
 	"modelInfo": {
 		"supportsImages": "Suporta imatges",
 		"noImages": "No suporta imatges",

webview-ui/src/i18n/locales/de/settings.json

@@ -503,6 +503,12 @@
 		"description": "Steuert die Zufälligkeit in den Antworten des Modells.",
 		"rangeDescription": "Höhere Werte machen die Ausgabe zufälliger, niedrigere Werte machen sie deterministischer."
 	},
+	"maxContextWindow": {
+		"maxContextWindow": "Maximales Kontextfenster",
+		"useCustom": "Benutzerdefiniertes maximales Kontextfenster verwenden",
+		"description": "Legt die maximale Kontextfenstergröße für das Modell fest. Wenn Konversationen diese Grenze erreichen, komprimiert Roo Code ältere Nachrichten automatisch, um die Beschränkung einzuhalten.",
+		"rangeDescription": "Höhere Werte ermöglichen längere Gespräche vor der Verdichtung, niedrigere Werte lösen eine frühere Verdichtung aus, um innerhalb der API-Ratengrenzen zu bleiben."
+	},
 	"modelInfo": {
 		"supportsImages": "Unterstützt Bilder",
 		"noImages": "Unterstützt keine Bilder",

webview-ui/src/i18n/locales/en/settings.json

@@ -503,6 +503,12 @@
 		"description": "Controls randomness in the model's responses.",
 		"rangeDescription": "Higher values make output more random, lower values make it more deterministic."
 	},
+	"maxContextWindow": {
+		"maxContextWindow": "Max Context Window",
+		"useCustom": "Use custom max context window",
+		"description": "Sets the maximum context window size for the model. When conversations approach this limit, Roo Code will automatically condense older messages to stay within the constraint.",
+		"rangeDescription": "Higher values allow longer conversations before condensing, lower values trigger condensing sooner to stay within API rate limits."
+	},
 	"modelInfo": {
 		"supportsImages": "Supports images",
 		"noImages": "Does not support images",

webview-ui/src/i18n/locales/es/settings.json

@@ -503,6 +503,12 @@
 		"description": "Controla la aleatoriedad en las respuestas del modelo.",
 		"rangeDescription": "Valores más altos hacen que la salida sea más aleatoria, valores más bajos la hacen más determinista."
 	},
+	"maxContextWindow": {
+		"maxContextWindow": "",
+		"useCustom": "Usar ventana de contexto máxima personalizada",
+		"description": "Establece el tamaño máximo de la ventana de contexto del modelo. Cuando las conversaciones se acercan a este límite, Roo Code condensará automáticamente los mensajes antiguos para ajustarse a la restricción.",
+		"rangeDescription": "Los valores más altos permiten conversaciones más largas antes de condensarse; los valores más bajos activan la condensación antes para permanecer dentro de los límites de velocidad de la API."
+	},
 	"modelInfo": {
 		"supportsImages": "Soporta imágenes",
 		"noImages": "No soporta imágenes",