feat(core): add enter_plan_mode tool (#18324)

2026-05-14 05:42:54 -07:00 · 2026-02-04 13:57:41 -05:00
parent bd156e6832
commit 650980af37
4 changed files with 306 additions and 0 deletions
@@ -0,0 +1,133 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  BaseDeclarativeTool,
+  BaseToolInvocation,
+  type ToolResult,
+  Kind,
+  type ToolInfoConfirmationDetails,
+  ToolConfirmationOutcome,
+} from './tools.js';
+import type { MessageBus } from '../confirmation-bus/message-bus.js';
+import type { Config } from '../config/config.js';
+import { ENTER_PLAN_MODE_TOOL_NAME } from './tool-names.js';
+import { ApprovalMode } from '../policy/types.js';
+
+export interface EnterPlanModeParams {
+  reason?: string;
+}
+
+export class EnterPlanModeTool extends BaseDeclarativeTool<
+  EnterPlanModeParams,
+  ToolResult
+> {
+  constructor(
+    private config: Config,
+    messageBus: MessageBus,
+  ) {
+    super(
+      ENTER_PLAN_MODE_TOOL_NAME,
+      'Enter Plan Mode',
+      'Switch to Plan Mode to safely research, design, and plan complex changes using read-only tools.',
+      Kind.Plan,
+      {
+        type: 'object',
+        properties: {
+          reason: {
+            type: 'string',
+            description:
+              'Short reason explaining why you are entering plan mode.',
+          },
+        },
+      },
+      messageBus,
+    );
+  }
+
+  protected createInvocation(
+    params: EnterPlanModeParams,
+    messageBus: MessageBus,
+    toolName: string,
+    toolDisplayName: string,
+  ): EnterPlanModeInvocation {
+    return new EnterPlanModeInvocation(
+      params,
+      messageBus,
+      toolName,
+      toolDisplayName,
+      this.config,
+    );
+  }
+}
+
+export class EnterPlanModeInvocation extends BaseToolInvocation<
+  EnterPlanModeParams,
+  ToolResult
+> {
+  private confirmationOutcome: ToolConfirmationOutcome | null = null;
+
+  constructor(
+    params: EnterPlanModeParams,
+    messageBus: MessageBus,
+    toolName: string,
+    toolDisplayName: string,
+    private config: Config,
+  ) {
+    super(params, messageBus, toolName, toolDisplayName);
+  }
+
+  getDescription(): string {
+    return this.params.reason || 'Initiating Plan Mode';
+  }
+
+  override async shouldConfirmExecute(
+    abortSignal: AbortSignal,
+  ): Promise<ToolInfoConfirmationDetails | false> {
+    const decision = await this.getMessageBusDecision(abortSignal);
+    if (decision === 'ALLOW') {
+      return false;
+    }
+
+    if (decision === 'DENY') {
+      throw new Error(
+        `Tool execution for "${
+          this._toolDisplayName || this._toolName
+        }" denied by policy.`,
+      );
+    }
+
+    // ASK_USER
+    return {
+      type: 'info',
+      title: 'Enter Plan Mode',
+      prompt:
+        'This will restrict the agent to read-only tools to allow for safe planning.',
+      onConfirm: async (outcome: ToolConfirmationOutcome) => {
+        this.confirmationOutcome = outcome;
+        await this.publishPolicyUpdate(outcome);
+      },
+    };
+  }
+
+  async execute(_signal: AbortSignal): Promise<ToolResult> {
+    if (this.confirmationOutcome === ToolConfirmationOutcome.Cancel) {
+      return {
+        llmContent: 'User cancelled entering Plan Mode.',
+        returnDisplay: 'Cancelled',
+      };
+    }
+
+    this.config.setApprovalMode(ApprovalMode.PLAN);
+
+    return {
+      llmContent: 'Switching to Plan mode.',
+      returnDisplay: this.params.reason
+        ? `Switching to Plan mode: ${this.params.reason}`
+        : 'Switching to Plan mode',
+    };
+  }
+}