diff --git a/packages/core/src/tools/memoryTool.test.ts b/packages/core/src/tools/memoryTool.test.ts
index aff0cc2e..5a9b5f26 100644
--- a/packages/core/src/tools/memoryTool.test.ts
+++ b/packages/core/src/tools/memoryTool.test.ts
@@ -15,6 +15,7 @@ import {
 import * as fs from 'fs/promises';
 import * as path from 'path';
 import * as os from 'os';
+import { ToolConfirmationOutcome } from './tools.js';
 
 // Mock dependencies
 vi.mock('fs/promises');
@@ -46,7 +47,7 @@ describe('MemoryTool', () => {
   };
 
   beforeEach(() => {
-    vi.mocked(os.homedir).mockReturnValue('/mock/home');
+    vi.mocked(os.homedir).mockReturnValue(path.join('/mock', 'home'));
     mockFsAdapter.readFile.mockReset();
     mockFsAdapter.writeFile.mockReset().mockResolvedValue(undefined);
     mockFsAdapter.mkdir
@@ -85,11 +86,15 @@ describe('MemoryTool', () => {
   });
 
   describe('performAddMemoryEntry (static method)', () => {
-    const testFilePath = path.join(
-      '/mock/home',
-      '.gemini',
-      DEFAULT_CONTEXT_FILENAME, // Use the default for basic tests
-    );
+    let testFilePath: string;
+
+    beforeEach(() => {
+      testFilePath = path.join(
+        os.homedir(),
+        '.gemini',
+        DEFAULT_CONTEXT_FILENAME,
+      );
+    });
 
     it('should create section and save a fact if file does not exist', async () => {
       mockFsAdapter.readFile.mockRejectedValue({ code: 'ENOENT' }); // Simulate file not found
@@ -206,7 +211,7 @@ describe('MemoryTool', () => {
       const result = await memoryTool.execute(params, mockAbortSignal);
       // Use getCurrentGeminiMdFilename for the default expectation before any setGeminiMdFilename calls in a test
       const expectedFilePath = path.join(
-        '/mock/home',
+        os.homedir(),
         '.gemini',
         getCurrentGeminiMdFilename(), // This will be DEFAULT_CONTEXT_FILENAME unless changed by a test
       );
@@ -262,4 +267,151 @@ describe('MemoryTool', () => {
       );
     });
   });
+
+  describe('shouldConfirmExecute', () => {
+    let memoryTool: MemoryTool;
+
+    beforeEach(() => {
+      memoryTool = new MemoryTool();
+      // Clear the allowlist before each test
+      (MemoryTool as unknown as { allowlist: Set<string> }).allowlist.clear();
+      // Mock fs.readFile to return empty string (file doesn't exist)
+      vi.mocked(fs.readFile).mockResolvedValue('');
+    });
+
+    it('should return confirmation details when memory file is not allowlisted', async () => {
+      const params = { fact: 'Test fact' };
+      const result = await memoryTool.shouldConfirmExecute(
+        params,
+        mockAbortSignal,
+      );
+
+      expect(result).toBeDefined();
+      expect(result).not.toBe(false);
+
+      if (result && result.type === 'edit') {
+        const expectedPath = path.join('~', '.gemini', 'GEMINI.md');
+        expect(result.title).toBe(`Confirm Memory Save: ${expectedPath}`);
+        expect(result.fileName).toContain(path.join('mock', 'home', '.gemini'));
+        expect(result.fileName).toContain('GEMINI.md');
+        expect(result.fileDiff).toContain('Index: GEMINI.md');
+        expect(result.fileDiff).toContain('+## Gemini Added Memories');
+        expect(result.fileDiff).toContain('+- Test fact');
+        expect(result.originalContent).toBe('');
+        expect(result.newContent).toContain('## Gemini Added Memories');
+        expect(result.newContent).toContain('- Test fact');
+      }
+    });
+
+    it('should return false when memory file is already allowlisted', async () => {
+      const params = { fact: 'Test fact' };
+      const memoryFilePath = path.join(
+        os.homedir(),
+        '.gemini',
+        getCurrentGeminiMdFilename(),
+      );
+
+      // Add the memory file to the allowlist
+      (MemoryTool as unknown as { allowlist: Set<string> }).allowlist.add(
+        memoryFilePath,
+      );
+
+      const result = await memoryTool.shouldConfirmExecute(
+        params,
+        mockAbortSignal,
+      );
+
+      expect(result).toBe(false);
+    });
+
+    it('should add memory file to allowlist when ProceedAlways is confirmed', async () => {
+      const params = { fact: 'Test fact' };
+      const memoryFilePath = path.join(
+        os.homedir(),
+        '.gemini',
+        getCurrentGeminiMdFilename(),
+      );
+
+      const result = await memoryTool.shouldConfirmExecute(
+        params,
+        mockAbortSignal,
+      );
+
+      expect(result).toBeDefined();
+      expect(result).not.toBe(false);
+
+      if (result && result.type === 'edit') {
+        // Simulate the onConfirm callback
+        await result.onConfirm(ToolConfirmationOutcome.ProceedAlways);
+
+        // Check that the memory file was added to the allowlist
+        expect(
+          (MemoryTool as unknown as { allowlist: Set<string> }).allowlist.has(
+            memoryFilePath,
+          ),
+        ).toBe(true);
+      }
+    });
+
+    it('should not add memory file to allowlist when other outcomes are confirmed', async () => {
+      const params = { fact: 'Test fact' };
+      const memoryFilePath = path.join(
+        os.homedir(),
+        '.gemini',
+        getCurrentGeminiMdFilename(),
+      );
+
+      const result = await memoryTool.shouldConfirmExecute(
+        params,
+        mockAbortSignal,
+      );
+
+      expect(result).toBeDefined();
+      expect(result).not.toBe(false);
+
+      if (result && result.type === 'edit') {
+        // Simulate the onConfirm callback with different outcomes
+        await result.onConfirm(ToolConfirmationOutcome.ProceedOnce);
+        expect(
+          (MemoryTool as unknown as { allowlist: Set<string> }).allowlist.has(
+            memoryFilePath,
+          ),
+        ).toBe(false);
+
+        await result.onConfirm(ToolConfirmationOutcome.Cancel);
+        expect(
+          (MemoryTool as unknown as { allowlist: Set<string> }).allowlist.has(
+            memoryFilePath,
+          ),
+        ).toBe(false);
+      }
+    });
+
+    it('should handle existing memory file with content', async () => {
+      const params = { fact: 'New fact' };
+      const existingContent =
+        'Some existing content.\n\n## Gemini Added Memories\n- Old fact\n';
+
+      // Mock fs.readFile to return existing content
+      vi.mocked(fs.readFile).mockResolvedValue(existingContent);
+
+      const result = await memoryTool.shouldConfirmExecute(
+        params,
+        mockAbortSignal,
+      );
+
+      expect(result).toBeDefined();
+      expect(result).not.toBe(false);
+
+      if (result && result.type === 'edit') {
+        const expectedPath = path.join('~', '.gemini', 'GEMINI.md');
+        expect(result.title).toBe(`Confirm Memory Save: ${expectedPath}`);
+        expect(result.fileDiff).toContain('Index: GEMINI.md');
+        expect(result.fileDiff).toContain('+- New fact');
+        expect(result.originalContent).toBe(existingContent);
+        expect(result.newContent).toContain('- Old fact');
+        expect(result.newContent).toContain('- New fact');
+      }
+    });
+  });
 });
diff --git a/packages/core/src/tools/memoryTool.ts b/packages/core/src/tools/memoryTool.ts
index f0f1e16b..96509f79 100644
--- a/packages/core/src/tools/memoryTool.ts
+++ b/packages/core/src/tools/memoryTool.ts
@@ -4,11 +4,21 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { BaseTool, Icon, ToolResult } from './tools.js';
+import {
+  BaseTool,
+  ToolResult,
+  ToolEditConfirmationDetails,
+  ToolConfirmationOutcome,
+  Icon,
+} from './tools.js';
 import { FunctionDeclaration, Type } from '@google/genai';
 import * as fs from 'fs/promises';
 import * as path from 'path';
 import { homedir } from 'os';
+import * as Diff from 'diff';
+import { DEFAULT_DIFF_OPTIONS } from './diffOptions.js';
+import { tildeifyPath } from '../utils/paths.js';
+import { ModifiableTool, ModifyContext } from './modifiable-tool.js';
 
 const memoryToolSchemaData: FunctionDeclaration = {
   name: 'save_memory',
@@ -80,6 +90,8 @@ export function getAllGeminiMdFilenames(): string[] {
 
 interface SaveMemoryParams {
   fact: string;
+  modified_by_user?: boolean;
+  modified_content?: string;
 }
 
 function getGlobalMemoryFilePath(): string {
@@ -98,7 +110,12 @@ function ensureNewlineSeparation(currentContent: string): string {
   return '\n\n';
 }
 
-export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
+export class MemoryTool
+  extends BaseTool<SaveMemoryParams, ToolResult>
+  implements ModifiableTool<SaveMemoryParams>
+{
+  private static readonly allowlist: Set<string> = new Set();
+
   static readonly Name: string = memoryToolSchemaData.name!;
   constructor() {
     super(
@@ -110,6 +127,111 @@ export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
     );
   }
 
+  getDescription(_params: SaveMemoryParams): string {
+    const memoryFilePath = getGlobalMemoryFilePath();
+    return `in ${tildeifyPath(memoryFilePath)}`;
+  }
+
+  /**
+   * Reads the current content of the memory file
+   */
+  private async readMemoryFileContent(): Promise<string> {
+    try {
+      return await fs.readFile(getGlobalMemoryFilePath(), 'utf-8');
+    } catch (err) {
+      const error = err as Error & { code?: string };
+      if (!(error instanceof Error) || error.code !== 'ENOENT') throw err;
+      return '';
+    }
+  }
+
+  /**
+   * Computes the new content that would result from adding a memory entry
+   */
+  private computeNewContent(currentContent: string, fact: string): string {
+    let processedText = fact.trim();
+    processedText = processedText.replace(/^(-+\s*)+/, '').trim();
+    const newMemoryItem = `- ${processedText}`;
+
+    const headerIndex = currentContent.indexOf(MEMORY_SECTION_HEADER);
+
+    if (headerIndex === -1) {
+      // Header not found, append header and then the entry
+      const separator = ensureNewlineSeparation(currentContent);
+      return (
+        currentContent +
+        `${separator}${MEMORY_SECTION_HEADER}\n${newMemoryItem}\n`
+      );
+    } else {
+      // Header found, find where to insert the new memory entry
+      const startOfSectionContent = headerIndex + MEMORY_SECTION_HEADER.length;
+      let endOfSectionIndex = currentContent.indexOf(
+        '\n## ',
+        startOfSectionContent,
+      );
+      if (endOfSectionIndex === -1) {
+        endOfSectionIndex = currentContent.length; // End of file
+      }
+
+      const beforeSectionMarker = currentContent
+        .substring(0, startOfSectionContent)
+        .trimEnd();
+      let sectionContent = currentContent
+        .substring(startOfSectionContent, endOfSectionIndex)
+        .trimEnd();
+      const afterSectionMarker = currentContent.substring(endOfSectionIndex);
+
+      sectionContent += `\n${newMemoryItem}`;
+      return (
+        `${beforeSectionMarker}\n${sectionContent.trimStart()}\n${afterSectionMarker}`.trimEnd() +
+        '\n'
+      );
+    }
+  }
+
+  async shouldConfirmExecute(
+    params: SaveMemoryParams,
+    _abortSignal: AbortSignal,
+  ): Promise<ToolEditConfirmationDetails | false> {
+    const memoryFilePath = getGlobalMemoryFilePath();
+    const allowlistKey = memoryFilePath;
+
+    if (MemoryTool.allowlist.has(allowlistKey)) {
+      return false;
+    }
+
+    // Read current content of the memory file
+    const currentContent = await this.readMemoryFileContent();
+
+    // Calculate the new content that will be written to the memory file
+    const newContent = this.computeNewContent(currentContent, params.fact);
+
+    const fileName = path.basename(memoryFilePath);
+    const fileDiff = Diff.createPatch(
+      fileName,
+      currentContent,
+      newContent,
+      'Current',
+      'Proposed',
+      DEFAULT_DIFF_OPTIONS,
+    );
+
+    const confirmationDetails: ToolEditConfirmationDetails = {
+      type: 'edit',
+      title: `Confirm Memory Save: ${tildeifyPath(memoryFilePath)}`,
+      fileName: memoryFilePath,
+      fileDiff,
+      originalContent: currentContent,
+      newContent,
+      onConfirm: async (outcome: ToolConfirmationOutcome) => {
+        if (outcome === ToolConfirmationOutcome.ProceedAlways) {
+          MemoryTool.allowlist.add(allowlistKey);
+        }
+      },
+    };
+    return confirmationDetails;
+  }
+
   static async performAddMemoryEntry(
     text: string,
     memoryFilePath: string,
@@ -184,7 +306,7 @@ export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
     params: SaveMemoryParams,
     _signal: AbortSignal,
   ): Promise<ToolResult> {
-    const { fact } = params;
+    const { fact, modified_by_user, modified_content } = params;
 
     if (!fact || typeof fact !== 'string' || fact.trim() === '') {
       const errorMessage = 'Parameter "fact" must be a non-empty string.';
@@ -195,17 +317,44 @@ export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
     }
 
     try {
-      // Use the static method with actual fs promises
-      await MemoryTool.performAddMemoryEntry(fact, getGlobalMemoryFilePath(), {
-        readFile: fs.readFile,
-        writeFile: fs.writeFile,
-        mkdir: fs.mkdir,
-      });
-      const successMessage = `Okay, I've remembered that: "${fact}"`;
-      return {
-        llmContent: JSON.stringify({ success: true, message: successMessage }),
-        returnDisplay: successMessage,
-      };
+      if (modified_by_user && modified_content !== undefined) {
+        // User modified the content in external editor, write it directly
+        await fs.mkdir(path.dirname(getGlobalMemoryFilePath()), {
+          recursive: true,
+        });
+        await fs.writeFile(
+          getGlobalMemoryFilePath(),
+          modified_content,
+          'utf-8',
+        );
+        const successMessage = `Okay, I've updated the memory file with your modifications.`;
+        return {
+          llmContent: JSON.stringify({
+            success: true,
+            message: successMessage,
+          }),
+          returnDisplay: successMessage,
+        };
+      } else {
+        // Use the normal memory entry logic
+        await MemoryTool.performAddMemoryEntry(
+          fact,
+          getGlobalMemoryFilePath(),
+          {
+            readFile: fs.readFile,
+            writeFile: fs.writeFile,
+            mkdir: fs.mkdir,
+          },
+        );
+        const successMessage = `Okay, I've remembered that: "${fact}"`;
+        return {
+          llmContent: JSON.stringify({
+            success: true,
+            message: successMessage,
+          }),
+          returnDisplay: successMessage,
+        };
+      }
     } catch (error) {
       const errorMessage =
         error instanceof Error ? error.message : String(error);
@@ -221,4 +370,25 @@ export class MemoryTool extends BaseTool<SaveMemoryParams, ToolResult> {
       };
     }
   }
+
+  getModifyContext(_abortSignal: AbortSignal): ModifyContext<SaveMemoryParams> {
+    return {
+      getFilePath: (_params: SaveMemoryParams) => getGlobalMemoryFilePath(),
+      getCurrentContent: async (_params: SaveMemoryParams): Promise<string> =>
+        this.readMemoryFileContent(),
+      getProposedContent: async (params: SaveMemoryParams): Promise<string> => {
+        const currentContent = await this.readMemoryFileContent();
+        return this.computeNewContent(currentContent, params.fact);
+      },
+      createUpdatedParams: (
+        _oldContent: string,
+        modifiedProposedContent: string,
+        originalParams: SaveMemoryParams,
+      ): SaveMemoryParams => ({
+        ...originalParams,
+        modified_by_user: true,
+        modified_content: modifiedProposedContent,
+      }),
+    };
+  }
 }