diff --git a/src/api/__tests__/index.spec.ts b/src/api/__tests__/index.spec.ts
index b86e73dac6..3617c3cd6d 100644
--- a/src/api/__tests__/index.spec.ts
+++ b/src/api/__tests__/index.spec.ts
@@ -9,21 +9,147 @@ vitest.mock("vscode", () => ({
 	},
 }))
 
-import type { ProviderSettings } from "@roo-code/types"
+// Handler constructors can require credentials or initialize SDK clients. Replace them
+// with inert classes so these tests exercise only the factory's routing behavior.
+vitest.mock("../providers", async () => {
+	const providers = await vitest.importActual<Record<string, unknown>>("../providers")
+
+	return Object.fromEntries(Object.keys(providers).map((name) => [name, class {}]))
+})
+
+vitest.mock("../providers/native-ollama", () => ({
+	NativeOllamaHandler: class {},
+}))
+
+import {
+	providerIdentifiers,
+	retiredProviderIdentifiers,
+	type ProviderName,
+	type ProviderNameWithRetired,
+} from "@roo-code/types"
 
 import { buildApiHandler } from "../index"
-import { KenariHandler } from "../providers/kenari"
+import {
+	AnthropicHandler,
+	AnthropicVertexHandler,
+	AwsBedrockHandler,
+	BasetenHandler,
+	DeepSeekHandler,
+	FakeAIHandler,
+	FireworksHandler,
+	FriendliHandler,
+	GeminiHandler,
+	KenariHandler,
+	KimiCodeHandler,
+	LiteLLMHandler,
+	LmStudioHandler,
+	MiniMaxHandler,
+	MimoHandler,
+	MistralHandler,
+	MoonshotHandler,
+	OpenAiCodexHandler,
+	OpenAiHandler,
+	OpenAiNativeHandler,
+	OpencodeGoHandler,
+	OpenRouterHandler,
+	PoeHandler,
+	QwenCodeHandler,
+	RequestyHandler,
+	SambaNovaHandler,
+	UnboundHandler,
+	VercelAiGatewayHandler,
+	VertexHandler,
+	VsCodeLmHandler,
+	XAIHandler,
+	ZAiHandler,
+	ZooGatewayHandler,
+} from "../providers"
+import { NativeOllamaHandler } from "../providers/native-ollama"
+
+type HandlerConstructor = new (...args: never[]) => object
+
+const expectedHandlers = {
+	[providerIdentifiers.anthropic]: AnthropicHandler,
+	[providerIdentifiers.openrouter]: OpenRouterHandler,
+	[providerIdentifiers.bedrock]: AwsBedrockHandler,
+	[providerIdentifiers.openai]: OpenAiHandler,
+	[providerIdentifiers.ollama]: NativeOllamaHandler,
+	[providerIdentifiers.lmstudio]: LmStudioHandler,
+	[providerIdentifiers.gemini]: GeminiHandler,
+	// Gemini CLI currently relies on the factory's default Anthropic handler.
+	[providerIdentifiers.geminiCli]: AnthropicHandler,
+	[providerIdentifiers.openaiCodex]: OpenAiCodexHandler,
+	[providerIdentifiers.openaiNative]: OpenAiNativeHandler,
+	[providerIdentifiers.deepseek]: DeepSeekHandler,
+	[providerIdentifiers.qwenCode]: QwenCodeHandler,
+	[providerIdentifiers.moonshot]: MoonshotHandler,
+	[providerIdentifiers.kimiCode]: KimiCodeHandler,
+	[providerIdentifiers.vscodeLm]: VsCodeLmHandler,
+	[providerIdentifiers.mistral]: MistralHandler,
+	[providerIdentifiers.requesty]: RequestyHandler,
+	[providerIdentifiers.unbound]: UnboundHandler,
+	[providerIdentifiers.fakeAi]: FakeAIHandler,
+	[providerIdentifiers.xai]: XAIHandler,
+	[providerIdentifiers.litellm]: LiteLLMHandler,
+	[providerIdentifiers.sambanova]: SambaNovaHandler,
+	[providerIdentifiers.mimo]: MimoHandler,
+	[providerIdentifiers.zai]: ZAiHandler,
+	[providerIdentifiers.fireworks]: FireworksHandler,
+	[providerIdentifiers.friendli]: FriendliHandler,
+	[providerIdentifiers.vercelAiGateway]: VercelAiGatewayHandler,
+	[providerIdentifiers.opencodeGo]: OpencodeGoHandler,
+	[providerIdentifiers.kenari]: KenariHandler,
+	[providerIdentifiers.zooGateway]: ZooGatewayHandler,
+	[providerIdentifiers.minimax]: MiniMaxHandler,
+	[providerIdentifiers.baseten]: BasetenHandler,
+	[providerIdentifiers.poe]: PoeHandler,
+} satisfies Record<Exclude<ProviderName, typeof providerIdentifiers.vertex>, HandlerConstructor>
+
+const expectedHandlerEntries = Object.entries(expectedHandlers) as Array<
+	[Exclude<ProviderName, typeof providerIdentifiers.vertex>, HandlerConstructor]
+>
 
 describe("buildApiHandler", () => {
-	it("returns a KenariHandler for the kenari provider", () => {
-		const configuration: ProviderSettings = {
-			apiProvider: "kenari",
-			kenariApiKey: "test-key",
-			kenariModelId: "glm-5-2",
-		}
+	it.each(expectedHandlerEntries)("returns the expected handler for %s", (apiProvider, Handler) => {
+		const handler = buildApiHandler({ apiProvider })
+
+		expect(handler).toBeInstanceOf(Handler)
+	})
+
+	it.each([
+		["an unspecified model", undefined, VertexHandler],
+		["non-Claude models", "non-claude-test-model", VertexHandler],
+		["Claude models", "claude-test-model", AnthropicVertexHandler],
+	] as const)("returns the expected Vertex handler for %s", (_description, apiModelId, Handler) => {
+		const handler = buildApiHandler({
+			apiProvider: providerIdentifiers.vertex,
+			apiModelId,
+		})
+
+		expect(handler).toBeInstanceOf(Handler)
+	})
+
+	it("preserves the dedicated removal error for the retired Roo provider", () => {
+		expect(() =>
+			buildApiHandler({
+				apiProvider: retiredProviderIdentifiers.roo,
+			}),
+		).toThrow("Roo Code Router has been removed")
+	})
+
+	it("rejects other retired providers", () => {
+		expect(() =>
+			buildApiHandler({
+				apiProvider: retiredProviderIdentifiers.cerebras,
+			}),
+		).toThrow("this provider is no longer supported")
+	})
 
-		const handler = buildApiHandler(configuration)
+	it("falls back to Anthropic for an unsupported provider value", () => {
+		const handler = buildApiHandler({
+			apiProvider: "unsupported-provider" as ProviderNameWithRetired,
+		})
 
-		expect(handler).toBeInstanceOf(KenariHandler)
+		expect(handler).toBeInstanceOf(AnthropicHandler)
 	})
 })
diff --git a/src/api/index.ts b/src/api/index.ts
index fccbf48867..c9992c9c39 100644
--- a/src/api/index.ts
+++ b/src/api/index.ts
@@ -1,7 +1,13 @@
 import { Anthropic } from "@anthropic-ai/sdk"
 import OpenAI from "openai"
 
-import { isRetiredProvider, type ProviderSettings, type ModelInfo } from "@roo-code/types"
+import {
+	isRetiredProvider,
+	providerIdentifiers,
+	retiredProviderIdentifiers,
+	type ProviderSettings,
+	type ModelInfo,
+} from "@roo-code/types"
 
 import { getRouterRemovalMessage } from "../core/config/routerRemoval"
 import { ApiStream } from "./transform/stream"
@@ -140,7 +146,7 @@ export interface ApiHandler {
 export function buildApiHandler(configuration: ProviderSettings): ApiHandler {
 	const { apiProvider, ...options } = configuration
 
-	if (apiProvider === "roo") {
+	if (apiProvider === retiredProviderIdentifiers.roo) {
 		throw new Error(getRouterRemovalMessage())
 	}
 
@@ -151,73 +157,73 @@ export function buildApiHandler(configuration: ProviderSettings): ApiHandler {
 	}
 
 	switch (apiProvider) {
-		case "anthropic":
+		case providerIdentifiers.anthropic:
 			return new AnthropicHandler(options)
-		case "openrouter":
+		case providerIdentifiers.openrouter:
 			return new OpenRouterHandler(options)
-		case "bedrock":
+		case providerIdentifiers.bedrock:
 			return new AwsBedrockHandler(options)
-		case "vertex":
+		case providerIdentifiers.vertex:
 			return options.apiModelId?.startsWith("claude")
 				? new AnthropicVertexHandler(options)
 				: new VertexHandler(options)
-		case "openai":
+		case providerIdentifiers.openai:
 			return new OpenAiHandler(options)
-		case "ollama":
+		case providerIdentifiers.ollama:
 			return new NativeOllamaHandler(options)
-		case "lmstudio":
+		case providerIdentifiers.lmstudio:
 			return new LmStudioHandler(options)
-		case "gemini":
+		case providerIdentifiers.gemini:
 			return new GeminiHandler(options)
-		case "openai-codex":
+		case providerIdentifiers.openaiCodex:
 			return new OpenAiCodexHandler(options)
-		case "openai-native":
+		case providerIdentifiers.openaiNative:
 			return new OpenAiNativeHandler(options)
-		case "deepseek":
+		case providerIdentifiers.deepseek:
 			return new DeepSeekHandler(options)
-		case "qwen-code":
+		case providerIdentifiers.qwenCode:
 			return new QwenCodeHandler(options)
-		case "moonshot":
+		case providerIdentifiers.moonshot:
 			return new MoonshotHandler(options)
-		case "kimi-code":
+		case providerIdentifiers.kimiCode:
 			return new KimiCodeHandler(options)
-		case "vscode-lm":
+		case providerIdentifiers.vscodeLm:
 			return new VsCodeLmHandler(options)
-		case "mistral":
+		case providerIdentifiers.mistral:
 			return new MistralHandler(options)
-		case "requesty":
+		case providerIdentifiers.requesty:
 			return new RequestyHandler(options)
-		case "unbound":
+		case providerIdentifiers.unbound:
 			return new UnboundHandler(options)
-		case "fake-ai":
+		case providerIdentifiers.fakeAi:
 			return new FakeAIHandler(options)
-		case "xai":
+		case providerIdentifiers.xai:
 			return new XAIHandler(options)
-		case "litellm":
+		case providerIdentifiers.litellm:
 			return new LiteLLMHandler(options)
-		case "sambanova":
+		case providerIdentifiers.sambanova:
 			return new SambaNovaHandler(options)
-		case "mimo":
+		case providerIdentifiers.mimo:
 			return new MimoHandler(options)
-		case "zai":
+		case providerIdentifiers.zai:
 			return new ZAiHandler(options)
-		case "fireworks":
+		case providerIdentifiers.fireworks:
 			return new FireworksHandler(options)
-		case "friendli":
+		case providerIdentifiers.friendli:
 			return new FriendliHandler(options)
-		case "vercel-ai-gateway":
+		case providerIdentifiers.vercelAiGateway:
 			return new VercelAiGatewayHandler(options)
-		case "opencode-go":
+		case providerIdentifiers.opencodeGo:
 			return new OpencodeGoHandler(options)
-		case "kenari":
+		case providerIdentifiers.kenari:
 			return new KenariHandler(options)
-		case "zoo-gateway":
+		case providerIdentifiers.zooGateway:
 			return new ZooGatewayHandler(options)
-		case "minimax":
+		case providerIdentifiers.minimax:
 			return new MiniMaxHandler(options)
-		case "baseten":
+		case providerIdentifiers.baseten:
 			return new BasetenHandler(options)
-		case "poe":
+		case providerIdentifiers.poe:
 			return new PoeHandler(options)
 		default:
 			return new AnthropicHandler(options)