diff --git a/packages/core/src/agent/config-loader.ts b/packages/core/src/agent/config-loader.ts
index 00c989a..84c2967 100644
--- a/packages/core/src/agent/config-loader.ts
+++ b/packages/core/src/agent/config-loader.ts
@@ -1,12 +1,12 @@
 import * as fs from 'fs';
 import * as path from 'path';
-import * as os from 'os';
 import type { AgentConfigFile } from './types.js';
+import { getConfigDir } from '../constants/paths.js';
 
 /**
  * 全局配置目录
  */
-const GLOBAL_CONFIG_DIR = path.join(os.homedir(), '.ai-terminal-assistant');
+const GLOBAL_CONFIG_DIR = getConfigDir();
 
 /**
  * 加载用户自定义 Agent 配置
diff --git a/packages/core/src/checkpoint/manager.ts b/packages/core/src/checkpoint/manager.ts
index 140c605..7efad2c 100644
--- a/packages/core/src/checkpoint/manager.ts
+++ b/packages/core/src/checkpoint/manager.ts
@@ -4,8 +4,8 @@
  */
 
 import * as path from 'path';
-import * as os from 'os';
 import { nanoid } from 'nanoid';
+import { getCheckpointsDir } from '../constants/paths.js';
 import { ShadowGit, createShadowGit } from './shadow-git.js';
 import { CheckpointLock } from './lock.js';
 import { CheckpointSafetyChecker } from './safety.js';
@@ -75,7 +75,7 @@ export class CheckpointManager {
       },
       maxCheckpoints: 100,
       maxAge: 7 * 24 * 60 * 60 * 1000,
-      storageDir: path.join(os.homedir(), '.ai-assist', 'checkpoints'),
+      storageDir: getCheckpointsDir(),
       ...config,
     };
 
diff --git a/packages/core/src/constants/index.ts b/packages/core/src/constants/index.ts
new file mode 100644
index 0000000..b3031d9
--- /dev/null
+++ b/packages/core/src/constants/index.ts
@@ -0,0 +1 @@
+export * from './paths.js';
diff --git a/packages/core/src/constants/paths.ts b/packages/core/src/constants/paths.ts
new file mode 100644
index 0000000..a45a396
--- /dev/null
+++ b/packages/core/src/constants/paths.ts
@@ -0,0 +1,60 @@
+/**
+ * 统一存储路径常量
+ * 所有数据统一存储在 ~/.ai-terminal-assistant/ 目录下
+ */
+
+import * as path from 'path';
+import * as os from 'os';
+
+/**
+ * 应用根目录名称
+ */
+export const APP_DIR_NAME = '.ai-terminal-assistant';
+
+/**
+ * 获取应用根目录
+ * ~/.ai-terminal-assistant/
+ */
+export function getAppDir(): string {
+  return path.join(os.homedir(), APP_DIR_NAME);
+}
+
+/**
+ * 获取配置目录（与应用根目录相同）
+ * ~/.ai-terminal-assistant/
+ */
+export function getConfigDir(): string {
+  return getAppDir();
+}
+
+/**
+ * 获取数据存储目录
+ * ~/.ai-terminal-assistant/data/
+ */
+export function getDataDir(): string {
+  return path.join(getAppDir(), 'data');
+}
+
+/**
+ * 获取 Checkpoint 存储目录
+ * ~/.ai-terminal-assistant/checkpoints/
+ */
+export function getCheckpointsDir(): string {
+  return path.join(getAppDir(), 'checkpoints');
+}
+
+/**
+ * 获取缓存目录
+ * ~/.ai-terminal-assistant/cache/
+ */
+export function getCacheDir(): string {
+  return path.join(getAppDir(), 'cache');
+}
+
+/**
+ * 获取日志目录
+ * ~/.ai-terminal-assistant/logs/
+ */
+export function getLogsDir(): string {
+  return path.join(getAppDir(), 'logs');
+}
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index bff5667..db511da 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -248,3 +248,14 @@ export type {
   FileIndexEntry,
   FileSearchOptions,
 } from './file-index/index.js';
+
+// Constants - 统一存储路径
+export {
+  APP_DIR_NAME,
+  getAppDir,
+  getConfigDir,
+  getDataDir,
+  getCheckpointsDir,
+  getCacheDir,
+  getLogsDir,
+} from './constants/index.js';
diff --git a/packages/core/src/mcp/config.ts b/packages/core/src/mcp/config.ts
index 8bc996e..ae88481 100644
--- a/packages/core/src/mcp/config.ts
+++ b/packages/core/src/mcp/config.ts
@@ -11,6 +11,7 @@ import type {
   LocalMCPServer,
   RemoteMCPServer,
 } from './types.js';
+import { getConfigDir } from '../constants/paths.js';
 
 /** 默认配置值 */
 const DEFAULTS = {
@@ -239,20 +240,20 @@ function mergeConfigs(base: MCPConfig, override: MCPConfig): MCPConfig {
 /**
  * 加载 MCP 配置
  * 按优先级从低到高加载：
- * 1. 用户级: ~/.ai-assist/config.{json,yaml}
+ * 1. 用户级: ~/.ai-terminal-assistant/mcp.{json,yaml}
  * 2. 项目级: .ai-assist/config.{json,yaml}
  */
 export function loadMCPConfig(workdir?: string): MCPConfig {
   const cwd = workdir || process.cwd();
-  const homeDir = process.env.HOME || process.env.USERPROFILE || '';
+  const configDir = getConfigDir();
 
   // 配置文件搜索路径
   const searchPaths = [
-    // 用户级配置
-    path.join(homeDir, '.ai-assist', 'config.json'),
-    path.join(homeDir, '.ai-assist', 'config.jsonc'),
-    path.join(homeDir, '.ai-assist', 'config.yaml'),
-    path.join(homeDir, '.ai-assist', 'config.yml'),
+    // 用户级配置（统一到 ~/.ai-terminal-assistant/）
+    path.join(configDir, 'mcp.json'),
+    path.join(configDir, 'mcp.jsonc'),
+    path.join(configDir, 'mcp.yaml'),
+    path.join(configDir, 'mcp.yml'),
     // 项目级配置
     path.join(cwd, '.ai-assist', 'config.json'),
     path.join(cwd, '.ai-assist', 'config.jsonc'),
diff --git a/packages/core/src/session/storage/base.ts b/packages/core/src/session/storage/base.ts
index dcc154f..7b4ee9b 100644
--- a/packages/core/src/session/storage/base.ts
+++ b/packages/core/src/session/storage/base.ts
@@ -1,8 +1,8 @@
 import * as fs from 'fs/promises';
 import * as path from 'path';
-import * as os from 'os';
 import { Lock } from '../../utils/lock.js';
 import { z } from 'zod';
+import { getDataDir } from '../../constants/paths.js';
 
 /**
  * 存储错误类型
@@ -19,14 +19,10 @@ export class StorageNotFoundError extends Error {
 
 /**
  * 获取默认存储目录
- * 遵循 XDG 规范：~/.local/share/ai-assist/
+ * 统一存储在 ~/.ai-terminal-assistant/data/
  */
 export function getDefaultStorageDir(): string {
-  const xdgDataHome = process.env.XDG_DATA_HOME;
-  if (xdgDataHome) {
-    return path.join(xdgDataHome, 'ai-assist');
-  }
-  return path.join(os.homedir(), '.local', 'share', 'ai-assist');
+  return getDataDir();
 }
 
 /**