refactor(api): address service tier review feedback

Author: WebMad

packages/types/src/model.ts

@@ -60,15 +60,15 @@ export const SERVICE_TIER_KEY = "service_tier"
 /**
  * Service tiers for the public OpenAI Responses API.
  */
-export enum OpenAiServiceTier {
-	Default = "default",
-	Flex = "flex",
-	Priority = "priority",
-}
+export const OpenAiServiceTier = {
+	Default: "default",
+	Flex: "flex",
+	Priority: "priority",
+} as const
 
-export const serviceTiers = Object.values(OpenAiServiceTier) as [`${OpenAiServiceTier}`, ...`${OpenAiServiceTier}`[]]
+export const serviceTiers = [OpenAiServiceTier.Default, OpenAiServiceTier.Flex, OpenAiServiceTier.Priority] as const
 export const serviceTierSchema = z.enum(serviceTiers)
-export type ServiceTier = `${OpenAiServiceTier}`
+export type ServiceTier = z.infer<typeof serviceTierSchema>
 
 /**
  * ModelParameter

src/api/providers/__tests__/openai-native.spec.ts

@@ -196,6 +196,60 @@ describe("OpenAiNativeHandler", () => {
 			},
 		)
 
+		it.each([
+			{
+				name: "an explicitly selected default tier",
+				modelId: "gpt-5.4" as const,
+				requestedTier: OpenAiServiceTier.Default,
+				resolvedTier: undefined,
+				expectedCost: 0.22,
+			},
+			{
+				name: "no selected service tier",
+				modelId: "gpt-5.4" as const,
+				requestedTier: undefined,
+				resolvedTier: undefined,
+				expectedCost: 0.22,
+			},
+			{
+				name: "a resolved service tier without a pricing entry",
+				modelId: "gpt-5.6-luna" as const,
+				requestedTier: OpenAiServiceTier.Default,
+				resolvedTier: OpenAiServiceTier.Priority,
+				expectedCost: 0.088,
+			},
+		])("retains standard pricing for $name", async ({ modelId, requestedTier, resolvedTier, expectedCost }) => {
+			mockResponsesCreate.mockResolvedValue({
+				async *[Symbol.asyncIterator]() {
+					yield {
+						type: "response.done",
+						response: {
+							...(resolvedTier ? { [SERVICE_TIER_KEY]: resolvedTier } : {}),
+							usage: {
+								input_tokens: 100_000,
+								output_tokens: 1_000,
+								cache_read_input_tokens: 20_000,
+							},
+						},
+					}
+				},
+			})
+			handler = new OpenAiNativeHandler({
+				...mockOptions,
+				apiModelId: modelId,
+				openAiNativeServiceTier: requestedTier,
+			})
+
+			const chunks = []
+			for await (const chunk of handler.createMessage(systemPrompt, messages)) {
+				chunks.push(chunk)
+			}
+
+			const usageChunk = chunks.find((chunk) => chunk.type === "usage")
+			expect(usageChunk).toBeDefined()
+			expect(usageChunk?.totalCost).toBeCloseTo(expectedCost, 6)
+		})
+
 		it.each(serviceTierPricingCases)(
 			"requests $requestedTier but prices manual SSE fallback usage using OpenAI's resolved $resolvedTier tier",
 			async ({ requestedTier, resolvedTier, expectedCost }) => {
@@ -550,49 +604,6 @@ describe("OpenAiNativeHandler", () => {
 			])
 		})
 
-		it("should retain standard pricing for an explicitly selected default tier", () => {
-			const defaultTierHandler = new OpenAiNativeHandler({
-				...mockOptions,
-				apiModelId: "gpt-5.4",
-				openAiNativeServiceTier: OpenAiServiceTier.Default,
-			})
-			const model = defaultTierHandler.getModel()
-			const normalizeUsage = Reflect.get(defaultTierHandler, "normalizeUsage")
-
-			const result = Reflect.apply(normalizeUsage, defaultTierHandler, [
-				{
-					input_tokens: 100_000,
-					output_tokens: 1_000,
-					cache_read_input_tokens: 20_000,
-				},
-				model,
-			]) as { totalCost: number }
-
-			expect(result.totalCost).toBeCloseTo(0.22, 6)
-		})
-
-		it("should retain standard pricing when no service tier is selected", () => {
-			const model = handler.getModel()
-			const applyServiceTierPricing = Reflect.get(handler, "applyServiceTierPricing")
-
-			const result = Reflect.apply(applyServiceTierPricing, handler, [model.info])
-
-			expect(result).toBe(model.info)
-		})
-
-		it("should retain standard pricing when the resolved service tier has no pricing entry", () => {
-			const model = handler.getModel()
-			const infoWithoutTiers = { ...model.info, tiers: undefined }
-			const applyServiceTierPricing = Reflect.get(handler, "applyServiceTierPricing")
-
-			const result = Reflect.apply(applyServiceTierPricing, handler, [
-				infoWithoutTiers,
-				OpenAiServiceTier.Priority,
-			])
-
-			expect(result).toBe(infoWithoutTiers)
-		})
-
 		it("should return GPT-5.3 Chat model info when selected", () => {
 			const chatHandler = new OpenAiNativeHandler({
 				...mockOptions,

src/api/providers/openai-native.ts

@@ -336,8 +336,7 @@ export class OpenAiNativeHandler extends BaseProvider implements SingleCompletio
 		}
 
 		// Validate requested tier against model support; if not supported, omit.
-		const allowedTierNames = new Set(model.info.tiers?.map((t) => t.name).filter(Boolean) || [])
-		const serviceTier = this.getAllowedServiceTier(this.options.openAiNativeServiceTier, allowedTierNames)
+		const serviceTier = this.getAllowedServiceTier(model)
 
 		// Decide whether to enable extended prompt cache retention for this request
 		const promptCacheRetention = this.getPromptCacheRetention(model)
@@ -1428,10 +1427,10 @@ export class OpenAiNativeHandler extends BaseProvider implements SingleCompletio
 		}
 	}
 
-	private getAllowedServiceTier(
-		requestedTier: ServiceTier | undefined,
-		allowedTierNames: ReadonlySet<string | undefined>,
-	): ServiceTier | undefined {
+	private getAllowedServiceTier(model: OpenAiNativeModel): ServiceTier | undefined {
+		const requestedTier = this.options.openAiNativeServiceTier
+		const allowedTierNames = new Set(model.info.tiers?.map(({ name }) => name).filter(Boolean))
+
 		return requestedTier === OpenAiServiceTier.Default || (requestedTier && allowedTierNames.has(requestedTier))
 			? requestedTier
 			: undefined
@@ -1514,8 +1513,7 @@ export class OpenAiNativeHandler extends BaseProvider implements SingleCompletio
 			}
 
 			// Include service tier if selected and supported
-			const allowedTierNames = new Set(model.info.tiers?.map((t) => t.name).filter(Boolean) || [])
-			const serviceTier = this.getAllowedServiceTier(this.options.openAiNativeServiceTier, allowedTierNames)
+			const serviceTier = this.getAllowedServiceTier(model)
 			if (serviceTier) {
 				requestBody[SERVICE_TIER_KEY] = serviceTier
 			}

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

@@ -1,6 +1,6 @@
 import { VSCodeLink } from "@vscode/webview-ui-toolkit/react"
 
-import { OpenAiServiceTier, providerIdentifiers, type ModelInfo } from "@roo-code/types"
+import { OpenAiServiceTier, providerIdentifiers, type ModelInfo, type ServiceTier } from "@roo-code/types"
 
 import { formatPrice } from "@src/utils/formatPrice"
 import { cn } from "@src/lib/utils"
@@ -18,7 +18,7 @@ type ModelInfoViewProps = {
 }
 
 type TierPricingRowProps = {
-	tier: OpenAiServiceTier
+	tier: ServiceTier
 	label: string
 	modelInfo?: ModelInfo
 }