feat(acp): extract and stream plan events from agent thoughts

- Updated default model configurations (Gemini 3/3.1) to enforce `includeThoughts: true` and `ThinkingLevel.HIGH` and updated schema, doc and tests to reflect this.
- Extended the code assist converters to safely extract and format the `thought` field, preventing type errors during `CountToken` API calls.
- Implemented real-time `extractPlanEntries` parsing using regex that gracefully extracts markdown task lists (e.g., `[TODO]`, `[x]`, `[]`) while safely ignoring content inside code blocks.
- Added logic in the ACP client that incrementally reads the agent's thought buffer and emits `sessionUpdate: 'plan'` events directly to the IDE whenever the tracked tasks change.
- Formatted `agent_thought_chunk` outputs to replace escaped literal newlines (`\n`) with actual native newlines, ensuring the IDE chat displays main thought sections cleanly without visual artifacts.
- Added comprehensive unit tests for the plan parser and ACP integration.

packages/cli/src/acp/acpClient.test.ts

@@ -91,52 +91,44 @@ vi.mock('../ui/commands/initCommand.js', () => ({
     action: vi.fn(),
   },
 }));
-vi.mock(
-  '@google/gemini-cli-core',
-  async (
-    importOriginal: () => Promise<typeof import('@google/gemini-cli-core')>,
-  ) => {
-    const actual = await importOriginal();
-    return {
-      ...actual,
-      ReadManyFilesTool: vi.fn().mockImplementation(() => ({
-        name: 'read_many_files',
-        kind: 'read',
-        build: vi.fn().mockReturnValue({
-          getDescription: () => 'Read files',
-          toolLocations: () => [],
-          execute: vi.fn().mockResolvedValue({
-            llmContent: ['--- file.txt ---\n\nFile content\n\n'],
-          }),
-        }),
-      })),
-      logToolCall: vi.fn(),
-      isWithinRoot: vi.fn().mockReturnValue(true),
-      LlmRole: {
-        MAIN: 'main',
-        SUBAGENT: 'subagent',
-        UTILITY_TOOL: 'utility_tool',
-        UTILITY_COMPRESSOR: 'utility_compressor',
-        UTILITY_SUMMARIZER: 'utility_summarizer',
-        UTILITY_ROUTER: 'utility_router',
-        UTILITY_LOOP_DETECTOR: 'utility_loop_detector',
-        UTILITY_NEXT_SPEAKER: 'utility_next_speaker',
-        UTILITY_EDIT_CORRECTOR: 'utility_edit_corrector',
-        UTILITY_AUTOCOMPLETE: 'utility_autocomplete',
-        UTILITY_FAST_ACK_HELPER: 'utility_fast_ack_helper',
-      },
-      CoreToolCallStatus: {
-        Validating: 'validating',
-        Scheduled: 'scheduled',
-        Error: 'error',
-        Success: 'success',
-        Executing: 'executing',
-        Cancelled: 'cancelled',
-        AwaitingApproval: 'awaiting_approval',
-      },
-    };
+const { actualCore } = await vi.hoisted(async () => {
+  const actual = await import('@google/gemini-cli-core');
+  return { actualCore: actual };
+});
+
+vi.mock('@google/gemini-cli-core', () => ({
+  ...actualCore,
+  ReadManyFilesTool: vi.fn().mockImplementation(() => ({
+    name: 'read_many_files',
+    kind: 'read',
+    build: vi.fn().mockReturnValue({
+      getDescription: () => 'Read files',
+      toolLocations: () => [],
+      execute: vi.fn().mockResolvedValue({
+        llmContent: ['--- file.txt ---\n\nFile content\n\n'],
+      }),
+    }),
+  })),
+  logToolCall: vi.fn(),
+  isWithinRoot: vi.fn().mockReturnValue(true),
+  // Ensure critical enums/objects are present if they were overridden
+  LlmRole: {
+    ...actualCore.LlmRole,
+    MAIN: 'main',
+    SUBAGENT: 'subagent',
+    UTILITY_TOOL: 'utility_tool',
   },
-);
+  CoreToolCallStatus: {
+    ...actualCore.CoreToolCallStatus,
+    Validating: 'validating',
+    Scheduled: 'scheduled',
+    Error: 'error',
+    Success: 'success',
+    Executing: 'executing',
+    Cancelled: 'cancelled',
+    AwaitingApproval: 'awaiting_approval',
+  },
+}));
 
 // Helper to create mock streams
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -1588,4 +1580,43 @@ describe('Session', () => {
 
     expect(handleCommandSpy).toHaveBeenCalledWith('/memory', expect.anything());
   });
+
+  it('should extract and emit plan events from thought chunks', async () => {
+    const stream = createMockStream([
+      {
+        type: StreamEventType.CHUNK,
+        value: {
+          candidates: [
+            {
+              content: {
+                parts: [
+                  {
+                    thought: '- [TODO] First task\n- [x] Done task',
+                  },
+                ],
+              },
+            },
+          ],
+        },
+      },
+    ]);
+    mockChat.sendMessageStream.mockResolvedValue(stream);
+
+    await session.prompt({
+      sessionId: 'session-1',
+      prompt: [{ type: 'text', text: 'Hi' }],
+    });
+
+    expect(mockConnection.sessionUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({
+        update: expect.objectContaining({
+          sessionUpdate: 'plan',
+          entries: [
+            { content: 'First task', status: 'pending', priority: 'medium' },
+            { content: 'Done task', status: 'completed', priority: 'medium' },
+          ],
+        }),
+      }),
+    );
+  });
 });

packages/cli/src/acp/acpClient.ts

@@ -49,6 +49,8 @@ import {
   getDisplayString,
 } from '@google/gemini-cli-core';
 import * as acp from '@agentclientprotocol/sdk';
+import { z } from 'zod';
+import { extractPlanEntries } from './planParser.js';
 import { AcpFileSystemService } from './fileSystemService.js';
 import { getAcpErrorMessage } from './acpErrors.js';
 import { Readable, Writable } from 'node:stream';
@@ -64,7 +66,6 @@ import {
 } from '../config/settings.js';
 import * as fs from 'node:fs/promises';
 import * as path from 'node:path';
-import { z } from 'zod';
 
 import { randomUUID } from 'node:crypto';
 import { loadCliConfig, type CliArgs } from '../config/config.js';
@@ -716,7 +717,7 @@ export class Session {
           (await this.config.getGemini31Launched?.()) ?? false,
         );
         const responseStream = await chat.sendMessageStream(
-          { model },
+          { model, isChatModel: true },
           nextMessage?.parts ?? [],
           promptId,
           pendingSend.signal,
@@ -724,6 +725,9 @@ export class Session {
         );
         nextMessage = null;
 
+        let currentThoughtTextBuffer = '';
+        let currentTurnPlanStr = '';
+
         for await (const resp of responseStream) {
           if (pendingSend.signal.aborted) {
             return { stopReason: CoreToolCallStatus.Cancelled };
@@ -736,13 +740,52 @@ export class Session {
           ) {
             const candidate = resp.value.candidates[0];
             for (const part of candidate.content?.parts ?? []) {
-              if (!part.text) {
+              const thoughtValue = (part as { thought?: unknown }).thought;
+              debugLogger.log(
+                `[ACP] Received part: thought=${
+                  thoughtValue ? typeof thoughtValue : 'undefined'
+                }, text=${part.text ? 'present' : 'empty'}`,
+              );
+              if (typeof thoughtValue === 'string') {
+                debugLogger.log(
+                  `[ACP] Thought content: ${thoughtValue.substring(0, 50)}...`,
+                );
+              }
+
+              if (part.thought) {
+                const thoughtSubText =
+                  typeof part.thought === 'string'
+                    ? part.thought
+                    : (part.text ?? '');
+                currentThoughtTextBuffer += thoughtSubText;
+                const entries = extractPlanEntries(currentThoughtTextBuffer);
+                if (entries) {
+                  const newPlanStr = JSON.stringify(entries);
+                  if (newPlanStr !== currentTurnPlanStr) {
+                    currentTurnPlanStr = newPlanStr;
+                    // eslint-disable-next-line @typescript-eslint/no-floating-promises
+                    this.sendUpdate({
+                      sessionUpdate: 'plan',
+                      entries,
+                    });
+                  }
+                }
+              }
+
+              const textToStream =
+                typeof part.thought === 'string'
+                  ? part.thought
+                  : (part.text ?? '');
+
+              if (!textToStream) {
                 continue;
               }
 
               const content: acp.ContentBlock = {
                 type: 'text',
-                text: part.text,
+                text: part.thought
+                  ? textToStream.replace(/\\n/g, '\n')
+                  : textToStream,
               };
 
               // eslint-disable-next-line @typescript-eslint/no-floating-promises

packages/cli/src/acp/planParser.test.ts

@@ -0,0 +1,56 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { extractPlanEntries } from './planParser.js';
+
+describe('planParser', () => {
+  it('should extract simple tasks', () => {
+    const text = `
+- [ ] Task 1
+- [x] Task 2
+- [/] Task 3
+    `;
+    const entries = extractPlanEntries(text);
+    expect(entries).toEqual([
+      { content: 'Task 1', status: 'pending', priority: 'medium' },
+      { content: 'Task 2', status: 'completed', priority: 'medium' },
+      { content: 'Task 3', status: 'in_progress', priority: 'medium' },
+    ]);
+  });
+
+  it('should ignore tasks in code blocks', () => {
+    const text = `
+- [ ] Valid task
+\`\`\`
+- [ ] Ignored task
+\`\`\`
+    `;
+    const entries = extractPlanEntries(text);
+    expect(entries).toEqual([
+      { content: 'Valid task', status: 'pending', priority: 'medium' },
+    ]);
+  });
+
+  it('should handle alternative status labels', () => {
+    const text = `
+1. [TODO] Task 1
+2. [DONE] Task 2
+3. [IN_PROGRESS] Task 3
+    `;
+    const entries = extractPlanEntries(text);
+    expect(entries).toEqual([
+      { content: 'Task 1', status: 'pending', priority: 'medium' },
+      { content: 'Task 2', status: 'completed', priority: 'medium' },
+      { content: 'Task 3', status: 'in_progress', priority: 'medium' },
+    ]);
+  });
+
+  it('should return null if no tasks are found', () => {
+    const text = 'Just some text without tasks.';
+    expect(extractPlanEntries(text)).toBeNull();
+  });
+});

packages/cli/src/acp/planParser.ts

@@ -0,0 +1,56 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { type PlanEntry } from '@agentclientprotocol/sdk';
+
+/**
+ * Extracts plan entries from the provided markdown text.
+ * It ignores content within triple-backtick code blocks.
+ */
+export function extractPlanEntries(text: string): PlanEntry[] | null {
+  // 1. Strip triple-backtick code blocks to avoid false positives.
+  const textWithoutCodeBlocks = text.replace(/```[\s\S]*?(?:```|$)/g, '');
+
+  // 2. Match markdown list items with task indicators.
+  // Supports: - [ ], - [x], - [/], 1. [TODO], 2. [DONE], - [] etc.
+  const taskRegex =
+    /^\s*(?:[-*]|\d+\.)\s*\[\s*(x|X|\/| |DONE|TODO|IN_PROGRESS|IN PROGRESS|PENDING|COMPLETED)?\s*\]\s+(.*?)$/gm;
+
+  const entries: PlanEntry[] = [];
+  let match;
+
+  while ((match = taskRegex.exec(textWithoutCodeBlocks)) !== null) {
+    const rawStatus = (match[1] || '').toUpperCase().trim();
+    const content = match[2].trim();
+
+    if (!content) continue;
+
+    let status: 'pending' | 'in_progress' | 'completed' = 'pending';
+
+    switch (rawStatus) {
+      case 'X':
+      case 'DONE':
+      case 'COMPLETED':
+        status = 'completed';
+        break;
+      case '/':
+      case 'IN_PROGRESS':
+      case 'IN PROGRESS':
+        status = 'in_progress';
+        break;
+      case '':
+      case 'TODO':
+      case 'PENDING':
+      default:
+        status = 'pending';
+        break;
+    }
+
+    entries.push({ content, status, priority: 'medium' });
+  }
+
+  return entries.length > 0 ? entries : null;
+}

packages/cli/src/ui/components/__snapshots__/ConfigInitDisplay.test.tsx.snap

@@ -18,20 +18,8 @@ Spinner Connecting to MCP servers... (0/5) - Waiting for: s1, s2, s3, +2 more
 "
 `;
 
-exports[`ConfigInitDisplay > truncates list of waiting servers if too many 2`] = `
-"
-Spinner Connecting to MCP servers... (0/5) - Waiting for: s1, s2, s3, +2 more
-"
-`;
-
 exports[`ConfigInitDisplay > updates message on McpClientUpdate event 1`] = `
 "
 Spinner Connecting to MCP servers... (1/2) - Waiting for: server2
 "
 `;
-
-exports[`ConfigInitDisplay > updates message on McpClientUpdate event 2`] = `
-"
-Spinner Connecting to MCP servers... (1/2) - Waiting for: server2
-"
-`;