diff --git a/src/core/sliding-window/__tests__/sliding-window.spec.ts b/src/core/sliding-window/__tests__/sliding-window.spec.ts
index 3bda5351d4..d3837c7a23 100644
--- a/src/core/sliding-window/__tests__/sliding-window.spec.ts
+++ b/src/core/sliding-window/__tests__/sliding-window.spec.ts
@@ -250,6 +250,30 @@ describe("Sliding Window", () => {
 			{ role: "assistant", content: "Fourth message" },
 			{ role: "user", content: "Fifth message" },
 		]
+		it("should use contextLimit as contextWindow when apiProvider is gemini", async () => {
+			const contextLimit = 2
+			const messages: ApiMessage[] = [
+				{ role: "user", content: "First message" },
+				{ role: "assistant", content: "Second message" },
+				{ role: "user", content: "Third message" },
+				{ role: "assistant", content: "Fourth message" },
+				{ role: "user", content: "" },
+			]
+			const result = await truncateConversationIfNeeded({
+				messages,
+				totalTokens: 2,
+				contextWindow: contextLimit,
+				maxTokens: null,
+				apiHandler: mockApiHandler,
+				autoCondenseContext: false,
+				autoCondenseContextPercent: 100,
+				systemPrompt: "",
+				taskId,
+				profileThresholds: {},
+				currentProfileId: "default",
+			})
+			expect(result.messages).toEqual([messages[0], messages[3], messages[4]])
+		})
 
 		it("should not truncate if tokens are below max tokens threshold", async () => {
 			const modelInfo = createModelInfo(100000, 30000)
diff --git a/webview-ui/src/components/settings/providers/Gemini.tsx b/webview-ui/src/components/settings/providers/Gemini.tsx
index 8f3f2b536b..54df49c392 100644
--- a/webview-ui/src/components/settings/providers/Gemini.tsx
+++ b/webview-ui/src/components/settings/providers/Gemini.tsx
@@ -198,7 +198,7 @@ export const Gemini = ({
 					<div className="flex items-center space-x-2">
 						<Slider
 							min={3000}
-							max={8192}
+							max={modelInfo.maxTokens}
 							step={1}
 							value={[apiConfiguration.maxOutputTokens ?? 0]}
 							onValueChange={(values: number[]) => setApiConfigurationField("maxOutputTokens", values[0])}
@@ -208,7 +208,10 @@ export const Gemini = ({
 							value={(apiConfiguration.maxOutputTokens ?? 0).toString()}
 							type="text"
 							inputMode="numeric"
-							onInput={handleInputChange("maxOutputTokens", (e) => parseInt((e as any).target.value, 10))}
+							onInput={handleInputChange("maxOutputTokens", (e) => {
+								const val = parseInt((e as any).target.value, 10)
+								return Number.isNaN(val) ? 0 : Math.min(val, modelInfo.maxTokens)
+							})}
 							className="w-16"
 						/>
 					</div>
diff --git a/webview-ui/src/components/settings/providers/__tests__/Gemini.spec.tsx b/webview-ui/src/components/settings/providers/__tests__/Gemini.spec.tsx
new file mode 100644
index 0000000000..7b69538ff9
--- /dev/null
+++ b/webview-ui/src/components/settings/providers/__tests__/Gemini.spec.tsx
@@ -0,0 +1,85 @@
+import React from "react"
+import { render, screen, fireEvent } from "@testing-library/react"
+import { Gemini } from "../Gemini"
+import type { ProviderSettings } from "@roo-code/types"
+import { geminiModels, geminiDefaultModelId, type GeminiModelId } from "@roo-code/types"
+
+vi.mock("@vscode/webview-ui-toolkit/react", () => ({
+	VSCodeTextField: ({ children, value, onInput, type }: any) => (
+		<div>
+			{children}
+			<input type={type} value={value} onChange={(e) => onInput(e)} />
+		</div>
+	),
+}))
+
+vi.mock("vscrui", () => ({
+	Checkbox: ({ children, checked, onChange }: any) => (
+		<label data-testid="checkbox-custom-context-limit">
+			<input type="checkbox" checked={checked} onChange={(e) => onChange(e.target.checked)} />
+			{children}
+		</label>
+	),
+}))
+
+vi.mock("@src/components/ui", () => ({
+	Slider: ({ min, max, step, value, onValueChange }: any) => (
+		<input
+			data-testid="slider"
+			type="range"
+			min={min}
+			max={max}
+			step={step}
+			value={value[0]}
+			onChange={(e) => onValueChange([Number(e.target.value)])}
+		/>
+	),
+}))
+
+vi.mock("@src/i18n/TranslationContext", () => ({
+	useAppTranslation: () => ({ t: (key: string) => key }),
+}))
+
+vi.mock("@src/components/common/VSCodeButtonLink", () => ({
+	VSCodeButtonLink: ({ children, href }: any) => <a href={href}>{children}</a>,
+}))
+
+const defaultModelId: GeminiModelId = geminiDefaultModelId
+const defaultContextWindow = geminiModels[defaultModelId].contextWindow
+
+describe("Gemini provider settings", () => {
+	it("does not render context limit slider when custom context limit is not enabled", () => {
+		const setApiField = vi.fn()
+		const config: ProviderSettings = {}
+		render(
+			<Gemini apiConfiguration={config} setApiConfigurationField={setApiField} currentModelId={defaultModelId} />,
+		)
+		expect(screen.queryByTestId("slider")).toBeNull()
+	})
+
+	it("enables custom context limit on checkbox toggle and shows slider with default value", () => {
+		const setApiField = vi.fn()
+		const config: ProviderSettings = {}
+		render(
+			<Gemini apiConfiguration={config} setApiConfigurationField={setApiField} currentModelId={defaultModelId} />,
+		)
+		const checkbox = screen.getByTestId("checkbox-custom-context-limit")
+		fireEvent.click(checkbox)
+		expect(setApiField).toHaveBeenCalledWith("contextLimit", defaultContextWindow)
+		const slider = screen.getByTestId("slider")
+		expect(slider).toHaveValue(defaultContextWindow.toString())
+	})
+
+	it("renders slider when contextLimit already set and updates on slider change", () => {
+		const setApiField = vi.fn()
+		const initialLimit = 100000
+		const config: ProviderSettings = { contextLimit: initialLimit }
+		render(
+			<Gemini apiConfiguration={config} setApiConfigurationField={setApiField} currentModelId={defaultModelId} />,
+		)
+		const slider = screen.getByTestId("slider")
+		expect(slider).toHaveValue(initialLimit.toString())
+		fireEvent.change(slider, { target: { value: "50000" } })
+		expect(setApiField).toHaveBeenCalledWith("contextLimit", 50000)
+	})
+})