feat: add support for Gemini Enterprise (Discovery Engine) assistant

- Implemented EnterpriseAgentProtocol and EnterpriseAgentSession in core
- Authenticates seamlessly via Application Default Credentials (ADC)
- Added robust brace-counting JSON stream parser with partial chunk caching
- Extracted and rendered immersive docArtifacts (markdown tables) E2E
- Integrated with CLI config schema and enabled default 'all tools' execution
- Added comprehensive unit tests verifying all stream events (thoughts, tools, tables)

TAG=agy
CONV=81e82460-f8cd-4c7b-a037-2cbedda4d3c0

packages/cli/src/config/config.ts

@@ -974,6 +974,7 @@ export async function loadCliConfig(
     mcpEnabled,
     extensionsEnabled,
     agents: settings.agents,
+    enterprise: settings.enterprise,
     adminSkillsEnabled,
     allowedMcpServers: mcpEnabled
       ? (argv.allowedMcpServerNames ?? settings.mcp?.allowed)

packages/cli/src/config/settingsSchema.ts

@@ -1366,6 +1366,44 @@ const SETTINGS_SCHEMA = {
       },
     },
   },
+  enterprise: {
+    type: 'object',
+    label: 'Gemini Enterprise',
+    category: 'Advanced',
+    requiresRestart: true,
+    default: {},
+    description: 'Settings for Gemini Enterprise integration.',
+    showInDialog: false,
+    properties: {
+      projectId: {
+        type: 'string',
+        label: 'Project ID',
+        category: 'Advanced',
+        requiresRestart: true,
+        default: undefined as string | undefined,
+        description: 'Google Cloud Project ID for Gemini Enterprise.',
+        showInDialog: true,
+      },
+      engineId: {
+        type: 'string',
+        label: 'Engine ID',
+        category: 'Advanced',
+        requiresRestart: true,
+        default: undefined as string | undefined,
+        description: 'Discovery Engine ID for Gemini Enterprise.',
+        showInDialog: true,
+      },
+      location: {
+        type: 'string',
+        label: 'Location',
+        category: 'Advanced',
+        requiresRestart: true,
+        default: 'global',
+        description: 'Google Cloud Location for Gemini Enterprise.',
+        showInDialog: true,
+      },
+    },
+  },
 
   context: {
     type: 'object',

packages/cli/src/gemini.tsx

@@ -507,7 +507,8 @@ export async function main() {
   // the sandbox because the sandbox will interfere with the Oauth2 web
   // redirect.
   let initialAuthFailed = false;
-  if (!settings.merged.security.auth.useExternal && !argv.isCommand) {
+  const useEnterprise = process.env['GEMINI_CLI_ENTERPRISE_AGENT'] === 'true';
+  if (!settings.merged.security.auth.useExternal && !argv.isCommand && !useEnterprise) {
     try {
       if (
         partialConfig.isInteractive() &&
@@ -858,13 +859,16 @@ export async function main() {
       ),
     );
 
-    const authType = await validateNonInteractiveAuth(
-      settings.merged.security.auth.selectedType,
-      settings.merged.security.auth.useExternal,
-      config,
-      settings,
-    );
-    await config.refreshAuth(authType);
+    const useEnterprise = process.env['GEMINI_CLI_ENTERPRISE_AGENT'] === 'true';
+    if (!useEnterprise) {
+      const authType = await validateNonInteractiveAuth(
+        settings.merged.security.auth.selectedType,
+        settings.merged.security.auth.useExternal,
+        config,
+        settings,
+      );
+      await config.refreshAuth(authType);
+    }
 
     if (config.getDebugMode()) {
       debugLogger.log('Session ID: %s', sessionId);

packages/cli/src/nonInteractiveCli.ts

@@ -66,7 +66,9 @@ interface RunNonInteractiveParams {
 export async function runNonInteractive(
   params: RunNonInteractiveParams,
 ): Promise<void> {
-  const useAgentSession = params.config.getAgentSessionNoninteractiveEnabled();
+  const useAgentSession =
+    params.config.getAgentSessionNoninteractiveEnabled() ||
+    process.env['GEMINI_CLI_ENTERPRISE_AGENT'] === 'true';
   if (useAgentSession) {
     debugLogger.debug(
       '[ADK] Running non-interactive mode with ADK agent session',

packages/cli/src/nonInteractiveCliAgentSession.ts

@@ -35,6 +35,7 @@ import {
   Scheduler,
   ROOT_SCHEDULER_ID,
   LegacyAgentSession,
+  EnterpriseAgentSession,
   ToolErrorType,
   geminiPartsToContentParts,
   displayContentToString,
@@ -295,13 +296,16 @@ export async function runNonInteractive({
         });
       }
 
-      // Create LegacyAgentSession — owns the agentic loop
-      const session = new LegacyAgentSession({
-        client: geminiClient,
-        scheduler,
-        config,
-        promptId: prompt_id,
-      });
+      const useEnterprise = process.env['GEMINI_CLI_ENTERPRISE_AGENT'] === 'true';
+      // Create AgentSession — owns the agentic loop
+      const session = useEnterprise
+        ? new EnterpriseAgentSession({ config, promptId: prompt_id })
+        : new LegacyAgentSession({
+            client: geminiClient,
+            scheduler,
+            config,
+            promptId: prompt_id,
+          });
 
       // Wire Ctrl+C to session abort
       abortSession = () => {

packages/cli/src/ui/AppContainer.tsx

@@ -90,6 +90,7 @@ import {
   logBillingEvent,
   ApiKeyUpdatedEvent,
   LegacyAgentProtocol,
+  EnterpriseAgentProtocol,
   type InjectionSource,
 } from '@google/gemini-cli-core';
 import { validateAuthMethod } from '../config/auth.js';
@@ -1173,10 +1174,14 @@ Logging in with Google... Restarting Gemini CLI to continue.
   }, [config]);
 
   const streamAgent = useMemo(
-    () =>
-      config?.getAgentSessionInteractiveEnabled()
+    () => {
+      if (process.env['GEMINI_CLI_ENTERPRISE_AGENT'] === 'true') {
+        return new EnterpriseAgentProtocol({ config });
+      }
+      return config?.getAgentSessionInteractiveEnabled()
         ? new LegacyAgentProtocol({ config, getPreferredEditor })
-        : undefined,
+        : undefined;
+    },
     [config, getPreferredEditor],
   );