feat(plan): add experimental plan flag (#16650)

packages/core/src/config/config.test.ts

@@ -1924,6 +1924,29 @@ describe('Config Quota & Preview Model Access', () => {
       expect(config.getModel()).toBe(PREVIEW_GEMINI_MODEL);
     });
   });
+
+  describe('isPlanEnabled', () => {
+    it('should return false by default', () => {
+      const config = new Config(baseParams);
+      expect(config.isPlanEnabled()).toBe(false);
+    });
+
+    it('should return true when plan is enabled', () => {
+      const config = new Config({
+        ...baseParams,
+        plan: true,
+      });
+      expect(config.isPlanEnabled()).toBe(true);
+    });
+
+    it('should return false when plan is explicitly disabled', () => {
+      const config = new Config({
+        ...baseParams,
+        plan: false,
+      });
+      expect(config.isPlanEnabled()).toBe(false);
+    });
+  });
 });
 
 describe('Config JIT Initialization', () => {

packages/core/src/config/config.ts

@@ -380,6 +380,7 @@ export interface ConfigParameters {
   adminSkillsEnabled?: boolean;
   experimentalJitContext?: boolean;
   disableLLMCorrection?: boolean;
+  plan?: boolean;
   onModelChange?: (model: string) => void;
   mcpEnabled?: boolean;
   extensionsEnabled?: boolean;
@@ -531,6 +532,7 @@ export class Config {
 
   private readonly experimentalJitContext: boolean;
   private readonly disableLLMCorrection: boolean;
+  private readonly planEnabled: boolean;
   private contextManager?: ContextManager;
   private terminalBackground: string | undefined = undefined;
   private remoteAdminSettings: GeminiCodeAssistSetting | undefined;
@@ -602,6 +604,7 @@ export class Config {
     this.enableAgents = params.enableAgents ?? false;
     this.agents = params.agents ?? {};
     this.disableLLMCorrection = params.disableLLMCorrection ?? false;
+    this.planEnabled = params.plan ?? false;
     this.skillsSupport = params.skillsSupport ?? false;
     this.disabledSkills = params.disabledSkills ?? [];
     this.adminSkillsEnabled = params.adminSkillsEnabled ?? true;
@@ -1469,6 +1472,10 @@ export class Config {
     return this.disableLLMCorrection;
   }
 
+  isPlanEnabled(): boolean {
+    return this.planEnabled;
+  }
+
   isAgentsEnabled(): boolean {
     return this.enableAgents;
   }