fix: auto-enable R1 format for models with preserveReasoning in preset picker

When selecting a model preset with preserveReasoning (e.g. Kimi K2.5,
Kimi K2 thinking), the R1 format setting is now automatically enabled
so reasoning/thinking blocks work correctly via OpenAI Compatible endpoints.

Also adds visual indicator showing applied capability flags after
selecting a preset, and new tests covering the auto-enable behavior.

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

@@ -64,6 +64,22 @@ export const OpenAICompatible = ({
 
 	const [openAiModels, setOpenAiModels] = useState<Record<string, ModelInfo> | null>(null)
 
+	// Compute applied capability flags for the selected preset
+	const appliedCapabilityFlags = useMemo(() => {
+		if (!selectedPresetId) return null
+		const preset = modelCapabilityPresets.find((p) => `${p.provider}/${p.modelId}` === selectedPresetId)
+		if (!preset) return null
+		const flags: string[] = []
+		if (preset.info.preserveReasoning)
+			flags.push(t("settings:providers.customModel.capabilityPreset.flags.reasoning"))
+		if (preset.info.supportsImages) flags.push(t("settings:providers.customModel.capabilityPreset.flags.images"))
+		if (preset.info.supportsPromptCache)
+			flags.push(t("settings:providers.customModel.capabilityPreset.flags.promptCache"))
+		if (preset.info.supportsTemperature)
+			flags.push(t("settings:providers.customModel.capabilityPreset.flags.temperature"))
+		return flags.length > 0 ? flags : null
+	}, [selectedPresetId, t])
+
 	// Group presets by provider for organized display
 	const groupedPresets = useMemo(() => {
 		const groups: Record<string, typeof modelCapabilityPresets> = {}
@@ -81,11 +97,17 @@ export const OpenAICompatible = ({
 			if (presetKey === "custom") {
 				setSelectedPresetId(null)
 				setApiConfigurationField("openAiCustomModelInfo", openAiModelInfoSaneDefaults)
+				setApiConfigurationField("openAiR1FormatEnabled", false)
 			} else {
 				const preset = modelCapabilityPresets.find((p) => `${p.provider}/${p.modelId}` === presetKey)
 				if (preset) {
 					setSelectedPresetId(presetKey)
 					setApiConfigurationField("openAiCustomModelInfo", { ...preset.info })
+
+					// Auto-enable R1 format for models that use reasoning/thinking blocks
+					if (preset.info.preserveReasoning) {
+						setApiConfigurationField("openAiR1FormatEnabled", true)
+					}
 				}
 			}
 			setPresetPickerOpen(false)
@@ -398,6 +420,12 @@ export const OpenAICompatible = ({
 							</Command>
 						</PopoverContent>
 					</Popover>
+					{appliedCapabilityFlags && (
+						<div className="text-xs text-vscode-descriptionForeground mt-1">
+							{t("settings:providers.customModel.capabilityPreset.appliedFlags")}:{" "}
+							{appliedCapabilityFlags.join(", ")}
+						</div>
+					)}
 				</div>
 
 				<div className="text-sm text-vscode-descriptionForeground whitespace-pre-line">

webview-ui/src/components/settings/providers/__tests__/OpenAICompatible.spec.tsx

@@ -430,4 +430,45 @@ describe("OpenAICompatible Component - Model Capability Presets", () => {
 			}),
 		)
 	})
+
+	it("should reset openAiR1FormatEnabled when selecting custom preset", () => {
+		const apiConfiguration: Partial<ProviderSettings> = {}
+
+		render(
+			<OpenAICompatible
+				apiConfiguration={apiConfiguration as ProviderSettings}
+				setApiConfigurationField={mockSetApiConfigurationField}
+				organizationAllowList={mockOrganizationAllowList}
+			/>,
+		)
+
+		const customItem = screen.getByTestId("command-item-custom")
+		fireEvent.click(customItem)
+
+		expect(mockSetApiConfigurationField).toHaveBeenCalledWith("openAiR1FormatEnabled", false)
+	})
+
+	it("should auto-enable openAiR1FormatEnabled when selecting a model with preserveReasoning", () => {
+		const apiConfiguration: Partial<ProviderSettings> = {}
+
+		render(
+			<OpenAICompatible
+				apiConfiguration={apiConfiguration as ProviderSettings}
+				setApiConfigurationField={mockSetApiConfigurationField}
+				organizationAllowList={mockOrganizationAllowList}
+			/>,
+		)
+
+		// Click on a Kimi K2.5 model which has preserveReasoning: true
+		const kimiItem = screen.getByTestId("command-item-Moonshot (Kimi)/kimi-k2.5")
+		fireEvent.click(kimiItem)
+
+		expect(mockSetApiConfigurationField).toHaveBeenCalledWith("openAiR1FormatEnabled", true)
+		expect(mockSetApiConfigurationField).toHaveBeenCalledWith(
+			"openAiCustomModelInfo",
+			expect.objectContaining({
+				preserveReasoning: true,
+			}),
+		)
+	})
 })

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

@@ -549,7 +549,14 @@
 				"custom": "Custom (configure manually)",
 				"searchPlaceholder": "Search models...",
 				"noResults": "No matching models found.",
-				"applied": "Applied capabilities from {{model}}"
+				"applied": "Applied capabilities from {{model}}",
+				"appliedFlags": "Applied capabilities",
+				"flags": {
+					"reasoning": "Reasoning/Thinking",
+					"images": "Image Support",
+					"promptCache": "Prompt Cache",
+					"temperature": "Temperature Control"
+				}
 			},
 			"capabilities": "Configure the capabilities and pricing for your custom OpenAI-compatible model. Be careful when specifying the model capabilities, as they can affect how Roo Code performs.",
 			"maxTokens": {