diff --git a/docs/extensions/reference.md b/docs/extensions/reference.md
index 2c2b730126..46d43225b2 100644
--- a/docs/extensions/reference.md
+++ b/docs/extensions/reference.md
@@ -122,7 +122,10 @@ The manifest file defines the extension's behavior and configuration.
     }
   },
   "contextFileName": "GEMINI.md",
-  "excludeTools": ["run_shell_command"]
+  "excludeTools": ["run_shell_command"],
+  "plan": {
+    "directory": ".gemini/plans"
+  }
 }
 ```
 
@@ -157,6 +160,11 @@ The manifest file defines the extension's behavior and configuration.
   `"excludeTools": ["run_shell_command(rm -rf)"]` will block the `rm -rf`
   command. Note that this differs from the MCP server `excludeTools`
   functionality, which can be listed in the MCP server config.
+- `plan`: Planning features configuration.
+  - `directory`: The directory where planning artifacts are stored. This serves
+    as a fallback if the user hasn't specified a plan directory in their
+    settings. If not specified by either the extension or the user, the default
+    is `~/.gemini/tmp/<project>/<session-id>/plans/`.
 
 When Gemini CLI starts, it loads all the extensions and merges their
 configurations. If there are any conflicts, the workspace configuration takes
diff --git a/packages/cli/src/config/config.test.ts b/packages/cli/src/config/config.test.ts
index 919ad86c51..b22b7412cc 100644
--- a/packages/cli/src/config/config.test.ts
+++ b/packages/cli/src/config/config.test.ts
@@ -19,6 +19,8 @@ import {
   debugLogger,
   ApprovalMode,
   type MCPServerConfig,
+  type GeminiCLIExtension,
+  Storage,
 } from '@google/gemini-cli-core';
 import { loadCliConfig, parseArguments, type CliArgs } from './config.js';
 import {
@@ -3524,4 +3526,101 @@ describe('loadCliConfig mcpEnabled', () => {
     expect(config.getAllowedMcpServers()).toEqual(['serverA']);
     expect(config.getBlockedMcpServers()).toEqual(['serverB']);
   });
+
+  describe('extension plan settings', () => {
+    beforeEach(() => {
+      vi.spyOn(Storage.prototype, 'getProjectTempDir').mockReturnValue(
+        '/mock/home/user/.gemini/tmp/test-project',
+      );
+    });
+
+    it('should use plan directory from active extension when user has not specified one', async () => {
+      process.argv = ['node', 'script.js'];
+      const settings = createTestMergedSettings({
+        experimental: { plan: true },
+      });
+      const argv = await parseArguments(settings);
+
+      vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([
+        {
+          name: 'ext-plan',
+          isActive: true,
+          plan: { directory: 'ext-plans-dir' },
+        } as unknown as GeminiCLIExtension,
+      ]);
+
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      expect(config.storage.getPlansDir()).toContain('ext-plans-dir');
+    });
+
+    it('should NOT use plan directory from active extension when user has specified one', async () => {
+      process.argv = ['node', 'script.js'];
+      const settings = createTestMergedSettings({
+        experimental: { plan: true },
+        general: {
+          plan: { directory: 'user-plans-dir' },
+        },
+      });
+      const argv = await parseArguments(settings);
+
+      vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([
+        {
+          name: 'ext-plan',
+          isActive: true,
+          plan: { directory: 'ext-plans-dir' },
+        } as unknown as GeminiCLIExtension,
+      ]);
+
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      expect(config.storage.getPlansDir()).toContain('user-plans-dir');
+      expect(config.storage.getPlansDir()).not.toContain('ext-plans-dir');
+    });
+
+    it('should NOT use plan directory from inactive extension', async () => {
+      process.argv = ['node', 'script.js'];
+      const settings = createTestMergedSettings({
+        experimental: { plan: true },
+      });
+      const argv = await parseArguments(settings);
+
+      vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([
+        {
+          name: 'ext-plan',
+          isActive: false,
+          plan: { directory: 'ext-plans-dir-inactive' },
+        } as unknown as GeminiCLIExtension,
+      ]);
+
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      expect(config.storage.getPlansDir()).not.toContain(
+        'ext-plans-dir-inactive',
+      );
+    });
+
+    it('should use default path if neither user nor extension settings provide a plan directory', async () => {
+      process.argv = ['node', 'script.js'];
+      const settings = createTestMergedSettings({
+        experimental: { plan: true },
+      });
+      const argv = await parseArguments(settings);
+
+      // No extensions providing plan directory
+      vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([]);
+
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      // Should return the default managed temp directory path
+      expect(config.storage.getPlansDir()).toBe(
+        path.join(
+          '/mock',
+          'home',
+          'user',
+          '.gemini',
+          'tmp',
+          'test-project',
+          'test-session',
+          'plans',
+        ),
+      );
+    });
+  });
 });
diff --git a/packages/cli/src/config/config.ts b/packages/cli/src/config/config.ts
index bbc8b1681e..b478d67478 100755
--- a/packages/cli/src/config/config.ts
+++ b/packages/cli/src/config/config.ts
@@ -511,6 +511,10 @@ export async function loadCliConfig(
   });
   await extensionManager.loadExtensions();
 
+  const extensionPlanSettings = extensionManager
+    .getExtensions()
+    .find((ext) => ext.isActive && ext.plan?.directory)?.plan;
+
   const experimentalJitContext = settings.experimental?.jitContext ?? false;
 
   let memoryContent: string | HierarchicalMemory = '';
@@ -827,7 +831,9 @@ export async function loadCliConfig(
     enableAgents: settings.experimental?.enableAgents,
     plan: settings.experimental?.plan,
     directWebFetch: settings.experimental?.directWebFetch,
-    planSettings: settings.general?.plan,
+    planSettings: settings.general?.plan?.directory
+      ? settings.general.plan
+      : (extensionPlanSettings ?? settings.general?.plan),
     enableEventDrivenScheduler: true,
     skillsSupport: settings.skills?.enabled ?? true,
     disabledSkills: settings.skills?.disabled,
diff --git a/packages/cli/src/config/extension-manager.ts b/packages/cli/src/config/extension-manager.ts
index 56152cd6e1..a9fce44635 100644
--- a/packages/cli/src/config/extension-manager.ts
+++ b/packages/cli/src/config/extension-manager.ts
@@ -886,6 +886,7 @@ Would you like to attempt to install via "git clone" instead?`,
         themes: config.themes,
         rules,
         checkers,
+        plan: config.plan,
       };
     } catch (e) {
       debugLogger.error(
diff --git a/packages/cli/src/config/extension.ts b/packages/cli/src/config/extension.ts
index 815cf23ece..04a7b885ca 100644
--- a/packages/cli/src/config/extension.ts
+++ b/packages/cli/src/config/extension.ts
@@ -33,6 +33,15 @@ export interface ExtensionConfig {
    * These themes will be registered when the extension is activated.
    */
   themes?: CustomTheme[];
+  /**
+   * Planning features configuration contributed by this extension.
+   */
+  plan?: {
+    /**
+     * The directory where planning artifacts are stored.
+     */
+    directory?: string;
+  };
 }
 
 export interface ExtensionUpdateInfo {
diff --git a/packages/core/src/config/config.test.ts b/packages/core/src/config/config.test.ts
index 83ee54f8e0..e587fc2e2e 100644
--- a/packages/core/src/config/config.test.ts
+++ b/packages/core/src/config/config.test.ts
@@ -2950,9 +2950,11 @@ describe('Plans Directory Initialization', () => {
 
   afterEach(() => {
     vi.mocked(fs.promises.mkdir).mockRestore();
+    vi.mocked(fs.promises.access).mockRestore?.();
   });
 
-  it('should create plans directory and add it to workspace context when plan is enabled', async () => {
+  it('should add plans directory to workspace context if it exists', async () => {
+    vi.spyOn(fs.promises, 'access').mockResolvedValue(undefined);
     const config = new Config({
       ...baseParams,
       plan: true,
@@ -2961,14 +2963,32 @@ describe('Plans Directory Initialization', () => {
     await config.initialize();
 
     const plansDir = config.storage.getPlansDir();
-    expect(fs.promises.mkdir).toHaveBeenCalledWith(plansDir, {
-      recursive: true,
-    });
+    // Should NOT create the directory eagerly
+    expect(fs.promises.mkdir).not.toHaveBeenCalled();
+    // Should check if it exists
+    expect(fs.promises.access).toHaveBeenCalledWith(plansDir);
 
     const context = config.getWorkspaceContext();
     expect(context.getDirectories()).toContain(plansDir);
   });
 
+  it('should NOT add plans directory to workspace context if it does not exist', async () => {
+    vi.spyOn(fs.promises, 'access').mockRejectedValue({ code: 'ENOENT' });
+    const config = new Config({
+      ...baseParams,
+      plan: true,
+    });
+
+    await config.initialize();
+
+    const plansDir = config.storage.getPlansDir();
+    expect(fs.promises.mkdir).not.toHaveBeenCalled();
+    expect(fs.promises.access).toHaveBeenCalledWith(plansDir);
+
+    const context = config.getWorkspaceContext();
+    expect(context.getDirectories()).not.toContain(plansDir);
+  });
+
   it('should NOT create plans directory or add it to workspace context when plan is disabled', async () => {
     const config = new Config({
       ...baseParams,
diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index 1a5c14b12c..258bd78f93 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -339,6 +339,15 @@ export interface GeminiCLIExtension {
    * Safety checkers contributed by this extension.
    */
   checkers?: SafetyCheckerRule[];
+  /**
+   * Planning features configuration contributed by this extension.
+   */
+  plan?: {
+    /**
+     * The directory where planning artifacts are stored.
+     */
+    directory?: string;
+  };
 }
 
 export interface ExtensionInstallMetadata {
@@ -1093,8 +1102,15 @@ export class Config implements McpContext {
     // Add plans directory to workspace context for plan file storage
     if (this.planEnabled) {
       const plansDir = this.storage.getPlansDir();
-      await fs.promises.mkdir(plansDir, { recursive: true });
-      this.workspaceContext.addDirectory(plansDir);
+      try {
+        await fs.promises.access(plansDir);
+        this.workspaceContext.addDirectory(plansDir);
+      } catch {
+        // Directory does not exist yet, so we don't add it to the workspace context.
+        // It will be created when the first plan is written. Since custom plan
+        // directories must be within the project root, they are automatically
+        // covered by the project-wide file discovery once created.
+      }
     }
 
     // Initialize centralized FileDiscoveryService