fix(mcp): skip sync when target CLI app is not installed

Add guard functions to check if Claude/Codex/Gemini CLI has been
initialized before attempting to sync MCP configurations. This prevents
creating unwanted config files in directories that don't exist.

- Claude: check ~/.claude dir OR ~/.claude.json file exists
- Codex: check ~/.codex dir exists
- Gemini: check ~/.gemini dir exists

When the target app is not installed, sync operations now silently
succeed without writing any files, allowing users to manage MCP servers
for apps they actually use without side effects on others.

src-tauri/tests/import_export_sync.rs

@@ -154,6 +154,12 @@ fn sync_enabled_to_codex_writes_enabled_servers() {
     let _guard = test_mutex().lock().expect("acquire test mutex");
     reset_test_fs();
 
+    // 模拟 Codex 已安装/已初始化：存在 ~/.codex 目录
+    let path = cc_switch_lib::get_codex_config_path();
+    if let Some(parent) = path.parent() {
+        fs::create_dir_all(parent).expect("create codex dir");
+    }
+
     let mut config = MultiAppConfig::default();
     config.mcp.codex.servers.insert(
         "stdio-enabled".into(),
@@ -170,7 +176,6 @@ fn sync_enabled_to_codex_writes_enabled_servers() {
 
     cc_switch_lib::sync_enabled_to_codex(&config).expect("sync codex");
 
-    let path = cc_switch_lib::get_codex_config_path();
     assert!(path.exists(), "config.toml should be created");
     let text = fs::read_to_string(&path).expect("read config.toml");
     assert!(
@@ -594,6 +599,11 @@ command = "echo"
 fn sync_claude_enabled_mcp_projects_to_user_config() {
     let _guard = test_mutex().lock().expect("acquire test mutex");
     reset_test_fs();
+    let home = ensure_test_home();
+
+    // 模拟 Claude 已安装/已初始化：存在 ~/.claude 目录
+    fs::create_dir_all(home.join(".claude")).expect("create claude dir");
+
     let mut config = MultiAppConfig::default();
 
     config.mcp.claude.servers.insert(

src-tauri/tests/mcp_commands.rs

@@ -247,11 +247,63 @@ fn set_mcp_enabled_for_codex_writes_live_config() {
     );
 }
 
+#[test]
+fn enabling_codex_mcp_skips_when_codex_dir_missing() {
+    use support::create_test_state;
+
+    let _guard = test_mutex().lock().expect("acquire test mutex");
+    reset_test_fs();
+    let home = ensure_test_home();
+
+    // 确认 Codex 配置目录不存在（模拟“未安装/未运行过 Codex CLI”）
+    assert!(
+        !home.join(".codex").exists(),
+        "~/.codex should not exist in fresh test environment"
+    );
+
+    let state = create_test_state().expect("create test state");
+
+    // 先插入一个未启用 Codex 的 MCP 服务器（避免 upsert 触发同步）
+    McpService::upsert_server(
+        &state,
+        McpServer {
+            id: "codex-server".to_string(),
+            name: "Codex Server".to_string(),
+            server: json!({
+                "type": "stdio",
+                "command": "echo"
+            }),
+            apps: McpApps {
+                claude: false,
+                codex: false,
+                gemini: false,
+            },
+            description: None,
+            homepage: None,
+            docs: None,
+            tags: Vec::new(),
+        },
+    )
+    .expect("insert server without syncing");
+
+    // 启用 Codex：目录缺失时应跳过写入（不创建 ~/.codex/config.toml）
+    McpService::toggle_app(&state, "codex-server", AppType::Codex, true)
+        .expect("toggle codex should succeed even when ~/.codex is missing");
+
+    assert!(
+        !home.join(".codex").exists(),
+        "~/.codex should still not exist after skipped sync"
+    );
+}
+
 #[test]
 fn upsert_mcp_server_disabling_app_removes_from_claude_live_config() {
     let _guard = test_mutex().lock().expect("acquire test mutex");
     reset_test_fs();
-    ensure_test_home();
+    let home = ensure_test_home();
+
+    // 模拟 Claude 已安装/已初始化：存在 ~/.claude 目录
+    fs::create_dir_all(home.join(".claude")).expect("create ~/.claude dir");
 
     // 先创建一个启用 Claude 的 MCP 服务器
     let state = support::create_test_state().expect("create test state");
@@ -400,3 +452,105 @@ fn import_mcp_from_gemini_sse_url_only_is_valid() {
         "Gemini url-only server should be normalized to type=sse in unified structure"
     );
 }
+
+#[test]
+fn enabling_gemini_mcp_skips_when_gemini_dir_missing() {
+    use support::create_test_state;
+
+    let _guard = test_mutex().lock().expect("acquire test mutex");
+    reset_test_fs();
+    let home = ensure_test_home();
+
+    // 确认 Gemini 配置目录不存在（模拟“未安装/未运行过 Gemini CLI”）
+    assert!(
+        !home.join(".gemini").exists(),
+        "~/.gemini should not exist in fresh test environment"
+    );
+
+    let state = create_test_state().expect("create test state");
+
+    // 先插入一个未启用 Gemini 的 MCP 服务器（避免 upsert 触发同步）
+    McpService::upsert_server(
+        &state,
+        McpServer {
+            id: "gemini-server".to_string(),
+            name: "Gemini Server".to_string(),
+            server: json!({
+                "type": "sse",
+                "url": "https://example.com/sse"
+            }),
+            apps: McpApps {
+                claude: false,
+                codex: false,
+                gemini: false,
+            },
+            description: None,
+            homepage: None,
+            docs: None,
+            tags: Vec::new(),
+        },
+    )
+    .expect("insert server without syncing");
+
+    // 启用 Gemini：目录缺失时应跳过写入（不创建 ~/.gemini/settings.json）
+    McpService::toggle_app(&state, "gemini-server", AppType::Gemini, true)
+        .expect("toggle gemini should succeed even when ~/.gemini is missing");
+
+    assert!(
+        !home.join(".gemini").exists(),
+        "~/.gemini should still not exist after skipped sync"
+    );
+}
+
+#[test]
+fn enabling_claude_mcp_skips_when_claude_config_absent() {
+    use support::create_test_state;
+
+    let _guard = test_mutex().lock().expect("acquire test mutex");
+    reset_test_fs();
+    let home = ensure_test_home();
+
+    // 确认 Claude 相关目录/文件都不存在（模拟“未安装/未运行过 Claude”）
+    assert!(
+        !home.join(".claude").exists(),
+        "~/.claude should not exist in fresh test environment"
+    );
+    assert!(
+        !home.join(".claude.json").exists(),
+        "~/.claude.json should not exist in fresh test environment"
+    );
+
+    let state = create_test_state().expect("create test state");
+
+    // 先插入一个未启用 Claude 的 MCP 服务器（避免 upsert 触发同步）
+    McpService::upsert_server(
+        &state,
+        McpServer {
+            id: "claude-server".to_string(),
+            name: "Claude Server".to_string(),
+            server: json!({
+                "type": "stdio",
+                "command": "echo"
+            }),
+            apps: McpApps {
+                claude: false,
+                codex: false,
+                gemini: false,
+            },
+            description: None,
+            homepage: None,
+            docs: None,
+            tags: Vec::new(),
+        },
+    )
+    .expect("insert server without syncing");
+
+    // 启用 Claude：配置缺失时应跳过写入（不创建 ~/.claude.json）
+    McpService::toggle_app(&state, "claude-server", AppType::Claude, true)
+        .expect("toggle claude should succeed even when ~/.claude is missing");
+
+    assert!(
+        !home.join(".claude.json").exists(),
+        "~/.claude.json should still not exist after skipped sync"
+    );
+}