feat(cli): add LiteLLM as a first-class provider

- Add "litellm" to supportedProviders in types.ts
- Add litellmBaseUrl to FlagOptions type
- Add LITELLM_API_KEY to environment variable mapping
- Add litellm case to getProviderSettings function
- Add --litellm-base-url CLI flag with default http://localhost:4000
- Add litellmBaseUrl to ExtensionHostOptions interface
- Add support for LITELLM_BASE_URL environment variable
- Add tests for LiteLLM provider functionality
- Update README with LiteLLM documentation

Closes #10839

apps/cli/README.md

@@ -156,12 +156,13 @@ Tokens are valid for 90 days. The CLI will prompt you to re-authenticate when yo
 | `-x, --exit-on-complete`          | Exit the process when task completes (useful for testing)                               | `false`                       |
 | `-y, --yes`                       | Non-interactive mode: auto-approve all actions                                          | `false`                       |
 | `-k, --api-key <key>`             | API key for the LLM provider                                                            | From env var                  |
-| `-p, --provider <provider>`       | API provider (anthropic, openai, openrouter, etc.)                                      | `openrouter`                  |
+| `-p, --provider <provider>`       | API provider (anthropic, openai, openrouter, litellm, etc.)                             | `openrouter`                  |
 | `-m, --model <model>`             | Model to use                                                                            | `anthropic/claude-sonnet-4.5` |
 | `-M, --mode <mode>`               | Mode to start in (code, architect, ask, debug, etc.)                                    | `code`                        |
 | `-r, --reasoning-effort <effort>` | Reasoning effort level (unspecified, disabled, none, minimal, low, medium, high, xhigh) | `medium`                      |
 | `--ephemeral`                     | Run without persisting state (uses temporary storage)                                   | `false`                       |
 | `--no-tui`                        | Disable TUI, use plain text output                                                      | `false`                       |
+| `--litellm-base-url <url>`        | Base URL for LiteLLM endpoint                                                           | `http://localhost:4000`       |
 
 ## Auth Commands
 
@@ -181,8 +182,16 @@ The CLI will look for API keys in environment variables if not provided via `--a
 | openai        | `OPENAI_API_KEY`     |
 | openrouter    | `OPENROUTER_API_KEY` |
 | google/gemini | `GOOGLE_API_KEY`     |
+| litellm       | `LITELLM_API_KEY`    |
 | ...           | ...                  |
 
+**LiteLLM Environment Variables:**
+
+| Variable           | Description                                                      |
+| ------------------ | ---------------------------------------------------------------- |
+| `LITELLM_API_KEY`  | API key for LiteLLM                                              |
+| `LITELLM_BASE_URL` | Base URL for LiteLLM endpoint (default: `http://localhost:4000`) |
+
 **Authentication Environment Variables:**
 
 | Variable          | Description                                                          |

apps/cli/src/agent/extension-host.ts

@@ -74,6 +74,10 @@ export interface ExtensionHostOptions {
 	 * running in an integration test and we want to see the output.
 	 */
 	integrationTest?: boolean
+	/**
+	 * Base URL for LiteLLM endpoint (only used when provider is "litellm").
+	 */
+	litellmBaseUrl?: string
 }
 
 interface ExtensionModule {
@@ -191,7 +195,12 @@ export class ExtensionHost extends EventEmitter implements ExtensionHostInterfac
 			commandExecutionTimeout: 30,
 			browserToolEnabled: false,
 			enableCheckpoints: false,
-			...getProviderSettings(this.options.provider, this.options.apiKey, this.options.model),
+			...getProviderSettings(
+				this.options.provider,
+				this.options.apiKey,
+				this.options.model,
+				this.options.litellmBaseUrl,
+			),
 		}
 
 		this.initialSettings = this.options.nonInteractive

apps/cli/src/commands/cli/run.ts

@@ -69,6 +69,12 @@ export async function run(promptArg: string | undefined, flagOptions: FlagOption
 		flagOptions.yes || flagOptions.dangerouslySkipPermissions || settings.dangerouslySkipPermissions || false
 	const effectiveExitOnComplete = flagOptions.print || flagOptions.oneshot || settings.oneshot || false
 
+	// Determine effective LiteLLM base URL: CLI flag > env var > default (when using litellm provider)
+	let effectiveLitellmBaseUrl: string | undefined = flagOptions.litellmBaseUrl || process.env.LITELLM_BASE_URL
+	if (effectiveProvider === "litellm" && !effectiveLitellmBaseUrl) {
+		effectiveLitellmBaseUrl = "http://localhost:4000"
+	}
+
 	const extensionHostOptions: ExtensionHostOptions = {
 		mode: effectiveMode,
 		reasoningEffort: effectiveReasoningEffort === "unspecified" ? undefined : effectiveReasoningEffort,
@@ -81,6 +87,7 @@ export async function run(promptArg: string | undefined, flagOptions: FlagOption
 		ephemeral: flagOptions.ephemeral,
 		debug: flagOptions.debug,
 		exitOnComplete: effectiveExitOnComplete,
+		litellmBaseUrl: effectiveLitellmBaseUrl,
 	}
 
 	// Roo Code Cloud Authentication

apps/cli/src/index.ts

@@ -35,6 +35,10 @@ program
 		'Output format (only works with --print): "text" (default), "json" (single result), or "stream-json" (realtime streaming)',
 		"text",
 	)
+	.option(
+		"--litellm-base-url <url>",
+		"Base URL for LiteLLM endpoint (default: http://localhost:4000 when using litellm provider)",
+	)
 	.action(run)
 
 const authCommand = program.command("auth").description("Manage authentication for Roo Code Cloud")

apps/cli/src/lib/utils/__tests__/provider.test.ts

@@ -1,4 +1,4 @@
-import { getApiKeyFromEnv } from "../provider.js"
+import { getApiKeyFromEnv, getProviderSettings } from "../provider.js"
 
 describe("getApiKeyFromEnv", () => {
 	const originalEnv = process.env
@@ -27,8 +27,51 @@ describe("getApiKeyFromEnv", () => {
 		expect(getApiKeyFromEnv("openai-native")).toBe("test-openai-key")
 	})
 
+	it("should return API key from environment variable for litellm", () => {
+		process.env.LITELLM_API_KEY = "test-litellm-key"
+		expect(getApiKeyFromEnv("litellm")).toBe("test-litellm-key")
+	})
+
 	it("should return undefined when API key is not set", () => {
 		delete process.env.ANTHROPIC_API_KEY
 		expect(getApiKeyFromEnv("anthropic")).toBeUndefined()
 	})
 })
+
+describe("getProviderSettings", () => {
+	it("should return LiteLLM settings with API key, model, and base URL", () => {
+		const settings = getProviderSettings("litellm", "test-api-key", "claude-3-sonnet", "http://localhost:4000")
+		expect(settings).toEqual({
+			apiProvider: "litellm",
+			litellmApiKey: "test-api-key",
+			litellmModelId: "claude-3-sonnet",
+			litellmBaseUrl: "http://localhost:4000",
+		})
+	})
+
+	it("should return LiteLLM settings without base URL when not provided", () => {
+		const settings = getProviderSettings("litellm", "test-api-key", "claude-3-sonnet")
+		expect(settings).toEqual({
+			apiProvider: "litellm",
+			litellmApiKey: "test-api-key",
+			litellmModelId: "claude-3-sonnet",
+		})
+	})
+
+	it("should return LiteLLM settings with only API key when model is not provided", () => {
+		const settings = getProviderSettings("litellm", "test-api-key", undefined)
+		expect(settings).toEqual({
+			apiProvider: "litellm",
+			litellmApiKey: "test-api-key",
+		})
+	})
+
+	it("should return anthropic settings correctly", () => {
+		const settings = getProviderSettings("anthropic", "test-api-key", "claude-3-opus")
+		expect(settings).toEqual({
+			apiProvider: "anthropic",
+			apiKey: "test-api-key",
+			apiModelId: "claude-3-opus",
+		})
+	})
+})

apps/cli/src/lib/utils/provider.ts

@@ -9,6 +9,7 @@ const envVarMap: Record<SupportedProvider, string> = {
 	openrouter: "OPENROUTER_API_KEY",
 	"vercel-ai-gateway": "VERCEL_AI_GATEWAY_API_KEY",
 	roo: "ROO_API_KEY",
+	litellm: "LITELLM_API_KEY",
 }
 
 export function getEnvVarName(provider: SupportedProvider): string {
@@ -24,6 +25,7 @@ export function getProviderSettings(
 	provider: SupportedProvider,
 	apiKey: string | undefined,
 	model: string | undefined,
+	baseUrl?: string,
 ): RooCodeSettings {
 	const config: RooCodeSettings = { apiProvider: provider }
 
@@ -52,6 +54,11 @@ export function getProviderSettings(
 			if (apiKey) config.rooApiKey = apiKey
 			if (model) config.apiModelId = model
 			break
+		case "litellm":
+			if (apiKey) config.litellmApiKey = apiKey
+			if (model) config.litellmModelId = model
+			if (baseUrl) config.litellmBaseUrl = baseUrl
+			break
 		default:
 			if (apiKey) config.apiKey = apiKey
 			if (model) config.apiModelId = model

apps/cli/src/types/types.ts

@@ -8,6 +8,7 @@ export const supportedProviders = [
 	"openrouter",
 	"vercel-ai-gateway",
 	"roo",
+	"litellm",
 ] as const satisfies ProviderName[]
 
 export type SupportedProvider = (typeof supportedProviders)[number]
@@ -34,6 +35,7 @@ export type FlagOptions = {
 	ephemeral: boolean
 	oneshot: boolean
 	outputFormat?: OutputFormat
+	litellmBaseUrl?: string
 }
 
 export enum OnboardingProviderChoice {