fix: correct LiteLLM baseURL handling when path is included

- Fix LiteLLMHandler to append /v1 to baseURL like other providers
- Fix getLiteLLMModels to properly join URLs preserving existing paths
- Add joinUrl helper function to avoid URL constructor path replacement
- Add test case for baseURL with paths
- Update existing tests to match new URL construction

Fixes #5696

src/api/providers/fetchers/__tests__/litellm.spec.ts

@@ -29,7 +29,28 @@ describe("getLiteLLMModels", () => {
 
 		await getLiteLLMModels("test-api-key", "http://localhost:4000/")
 
-		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/v1/model/info", {
+		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/model/info", {
+			headers: {
+				Authorization: "Bearer test-api-key",
+				"Content-Type": "application/json",
+				...DEFAULT_HEADERS,
+			},
+			timeout: 5000,
+		})
+	})
+
+	it("handles base URLs with paths correctly", async () => {
+		const mockResponse = {
+			data: {
+				data: [],
+			},
+		}
+
+		mockedAxios.get.mockResolvedValue(mockResponse)
+
+		await getLiteLLMModels("test-api-key", "http://localhost:4000/litellm")
+
+		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/litellm/model/info", {
 			headers: {
 				Authorization: "Bearer test-api-key",
 				"Content-Type": "application/json",
@@ -81,7 +102,7 @@ describe("getLiteLLMModels", () => {
 
 		const result = await getLiteLLMModels("test-api-key", "http://localhost:4000")
 
-		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/v1/model/info", {
+		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/model/info", {
 			headers: {
 				Authorization: "Bearer test-api-key",
 				"Content-Type": "application/json",
@@ -125,7 +146,7 @@ describe("getLiteLLMModels", () => {
 
 		await getLiteLLMModels("", "http://localhost:4000")
 
-		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/v1/model/info", {
+		expect(mockedAxios.get).toHaveBeenCalledWith("http://localhost:4000/model/info", {
 			headers: {
 				"Content-Type": "application/json",
 				...DEFAULT_HEADERS,
@@ -257,7 +278,7 @@ describe("getLiteLLMModels", () => {
 		await getLiteLLMModels("test-api-key", "http://localhost:4000")
 
 		expect(mockedAxios.get).toHaveBeenCalledWith(
-			"http://localhost:4000/v1/model/info",
+			"http://localhost:4000/model/info",
 			expect.objectContaining({
 				timeout: 5000,
 			}),

src/api/providers/fetchers/litellm.ts

@@ -5,6 +5,20 @@ import { LITELLM_COMPUTER_USE_MODELS } from "@roo-code/types"
 import type { ModelRecord } from "../../../shared/api"
 
 import { DEFAULT_HEADERS } from "../constants"
+
+/**
+ * Properly joins a base URL with a path, preserving any existing path in the base URL
+ * @param baseUrl The base URL (may include a path)
+ * @param path The path to append
+ * @returns The properly joined URL
+ */
+function joinUrl(baseUrl: string, path: string): string {
+	// Remove trailing slash from baseUrl and leading slash from path
+	const cleanBaseUrl = baseUrl.replace(/\/$/, "")
+	const cleanPath = path.replace(/^\//, "")
+	return `${cleanBaseUrl}/${cleanPath}`
+}
+
 /**
  * Fetches available models from a LiteLLM server
  *
@@ -23,8 +37,8 @@ export async function getLiteLLMModels(apiKey: string, baseUrl: string): Promise
 		if (apiKey) {
 			headers["Authorization"] = `Bearer ${apiKey}`
 		}
-		// Use URL constructor to properly join base URL and path
-		const url = new URL("/v1/model/info", baseUrl).href
+		// Use helper function to properly join base URL and path, preserving any existing path
+		const url = joinUrl(baseUrl, "model/info")
 		// Added timeout to prevent indefinite hanging
 		const response = await axios.get(url, { headers, timeout: 5000 })
 		const models: ModelRecord = {}

src/api/providers/lite-llm.ts

@@ -24,7 +24,7 @@ export class LiteLLMHandler extends RouterProvider implements SingleCompletionHa
 		super({
 			options,
 			name: "litellm",
-			baseURL: `${options.litellmBaseUrl || "http://localhost:4000"}`,
+			baseURL: `${options.litellmBaseUrl || "http://localhost:4000"}/v1`,
 			apiKey: options.litellmApiKey || "dummy-key",
 			modelId: options.litellmModelId,
 			defaultModelId: litellmDefaultModelId,