diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 98ff01073..38ac49e5c 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -55,6 +55,7 @@ pub use prompt::Prompt;
 pub use provider::{Provider, ProviderMeta};
 pub use services::{
     profile::{ProfilePayload, ProfileScope, ProfileService},
+    provider::reapply_current_codex_official_live,
     skill::{migrate_skills_to_ssot, ImportSkillSelection},
     ConfigService, EndpointLatency, McpService, PromptService, ProviderService, ProxyService,
     SkillService, SpeedtestService,
diff --git a/src-tauri/src/services/mcp.rs b/src-tauri/src/services/mcp.rs
index ed07c56fe..67bb2b66e 100644
--- a/src-tauri/src/services/mcp.rs
+++ b/src-tauri/src/services/mcp.rs
@@ -181,16 +181,35 @@ impl McpService {
         let servers = Self::get_all_servers(state)?;
 
         for app in AppType::all() {
-            if matches!(app, AppType::OpenClaw | AppType::ClaudeDesktop) {
-                continue;
-            }
+            Self::project_servers_to_app(state, &servers, &app)?;
+        }
 
-            for server in servers.values() {
-                if server.apps.is_enabled_for(&app) {
-                    Self::sync_server_to_app(state, server, &app)?;
-                } else {
-                    Self::remove_server_from_app(state, &server.id, &app)?;
-                }
+        Ok(())
+    }
+
+    /// 只把启用状态投影到单个应用。某个应用的 live 被整体重写后用它做
+    /// 定向重投影：sync_all_enabled 按 AppType::all() 顺序逐应用短路，
+    /// 排在前面的无关应用 live 损坏（如 ~/.claude.json 坏 JSON）会阻断
+    /// 后面应用的投影。
+    pub fn sync_enabled_for_app(state: &AppState, app: &AppType) -> Result<(), AppError> {
+        let servers = Self::get_all_servers(state)?;
+        Self::project_servers_to_app(state, &servers, app)
+    }
+
+    fn project_servers_to_app(
+        state: &AppState,
+        servers: &IndexMap<String, McpServer>,
+        app: &AppType,
+    ) -> Result<(), AppError> {
+        if matches!(app, AppType::OpenClaw | AppType::ClaudeDesktop) {
+            return Ok(());
+        }
+
+        for server in servers.values() {
+            if server.apps.is_enabled_for(app) {
+                Self::sync_server_to_app(state, server, app)?;
+            } else {
+                Self::remove_server_from_app(state, &server.id, app)?;
             }
         }
 
diff --git a/src-tauri/src/services/provider/mod.rs b/src-tauri/src/services/provider/mod.rs
index 6d3368c1a..c804db291 100644
--- a/src-tauri/src/services/provider/mod.rs
+++ b/src-tauri/src/services/provider/mod.rs
@@ -81,6 +81,18 @@ pub fn reapply_current_codex_official_live(state: &AppState) -> Result<bool, App
     }
 
     live::write_live_with_common_config(&state.db, &AppType::Codex, provider)?;
+    // 重写 live 会整体替换 config.toml（有意设计），[mcp_servers] 随之丢失，
+    // 写完必须立刻从 DB 重新投影启用的 MCP。只投影 Codex 而非
+    // sync_all_enabled：后者按 AppType::all() 顺序逐应用短路，排在 Codex
+    // 前面的无关应用 live 损坏（如 ~/.claude.json 坏 JSON）会阻断 Codex
+    // 的重投影，让刚被清掉的 [mcp_servers] 无人补回。
+    // 投影失败降级为警告：走到这里 live 已按新开关状态落盘，开关事实上
+    // 已生效；若把错误上抛，save_settings 会回滚开关设置，制造"设置=旧值、
+    // live=新桶"的会话分裂——正是该回滚要防止的状态。MCP 投影可自愈
+    // （下次切换 / 任一 MCP 启停操作都会重新投影）。
+    if let Err(err) = McpService::sync_enabled_for_app(state, &AppType::Codex) {
+        log::warn!("统一会话开关重写 live 后重投影 Codex MCP 失败（将在下次同步时自愈）: {err}");
+    }
     Ok(true)
 }
 
diff --git a/src-tauri/tests/provider_service.rs b/src-tauri/tests/provider_service.rs
index 4111e19ba..579a7e0d0 100644
--- a/src-tauri/tests/provider_service.rs
+++ b/src-tauri/tests/provider_service.rs
@@ -881,6 +881,203 @@ requires_openai_auth = true
     );
 }
 
+#[test]
+fn reapply_codex_official_live_resyncs_mcp_servers() {
+    let _guard = test_mutex().lock().expect("acquire test mutex");
+    reset_test_fs();
+    let _home = ensure_test_home();
+
+    let live_auth = json!({
+        "auth_mode": "chatgpt",
+        "OPENAI_API_KEY": null,
+        "tokens": { "access_token": "official-oauth-token", "account_id": "acct" }
+    });
+    write_codex_live_atomic(&live_auth, Some("")).expect("seed official live auth");
+
+    let mut initial_config = MultiAppConfig::default();
+    {
+        let manager = initial_config
+            .get_manager_mut(&AppType::Codex)
+            .expect("codex manager");
+        let mut official = Provider::with_id(
+            "official-provider".to_string(),
+            "Official".to_string(),
+            json!({
+                "auth": {
+                    "auth_mode": "chatgpt",
+                    "OPENAI_API_KEY": null,
+                    "tokens": { "access_token": "official-oauth-token", "account_id": "acct" }
+                },
+                "config": ""
+            }),
+            None,
+        );
+        official.category = Some("official".to_string());
+        manager
+            .providers
+            .insert("official-provider".to_string(), official);
+    }
+    let servers = initial_config
+        .mcp
+        .servers
+        .get_or_insert_with(Default::default);
+    servers.insert(
+        "echo-server".into(),
+        McpServer {
+            id: "echo-server".into(),
+            name: "Echo Server".into(),
+            server: json!({
+                "type": "stdio",
+                "command": "echo"
+            }),
+            apps: McpApps {
+                claude: false,
+                codex: true,
+                gemini: false,
+                opencode: false,
+                hermes: false,
+            },
+            description: None,
+            homepage: None,
+            docs: None,
+            tags: Vec::new(),
+        },
+    );
+
+    let state = create_test_state_with_config(&initial_config).expect("create test state");
+
+    ProviderService::switch(&state, AppType::Codex, "official-provider")
+        .expect("switch to official provider");
+    let live = std::fs::read_to_string(cc_switch_lib::get_codex_config_path())
+        .expect("read config.toml after switch");
+    assert!(
+        live.contains("mcp_servers.echo-server"),
+        "switch should sync enabled MCP servers into live"
+    );
+
+    // 统一会话开关变更触发的 reapply 会整体重写 live config.toml（有意设计），
+    // 写完必须重新投影 DB 里启用的 MCP，否则用户的 MCP 会静默失效。
+    let reapplied =
+        cc_switch_lib::reapply_current_codex_official_live(&state).expect("reapply official live");
+    assert!(
+        reapplied,
+        "current provider is official, reapply should run"
+    );
+
+    let live = std::fs::read_to_string(cc_switch_lib::get_codex_config_path())
+        .expect("read config.toml after reapply");
+    assert!(
+        live.contains("mcp_servers.echo-server"),
+        "reapply must re-project enabled MCP servers after the full live rewrite, got: {live}"
+    );
+}
+
+/// reapply 走到 MCP 投影时 live 已按新开关状态落盘、开关事实上已生效：
+/// ① 投影失败若上抛，save_settings 会回滚开关设置，制造"设置=旧值、
+/// live=新桶"的会话分裂——必须降级为警告而不是失败；
+/// ② 投影必须只针对 Codex：sync_all_enabled 按 AppType::all() 顺序短路，
+/// Claude 排在 Codex 前面，损坏的 ~/.claude.json 会在轮到 Codex 之前
+/// 报错——若吞错了事，刚被整体重写清掉的 [mcp_servers] 就无人补回，
+/// Codex MCP 静默消失。这里用坏 JSON 的 ~/.claude.json 复现该场景。
+#[test]
+fn reapply_codex_official_live_projects_mcp_despite_broken_claude_json() {
+    let _guard = test_mutex().lock().expect("acquire test mutex");
+    reset_test_fs();
+    let _home = ensure_test_home();
+
+    let live_auth = json!({
+        "auth_mode": "chatgpt",
+        "OPENAI_API_KEY": null,
+        "tokens": { "access_token": "official-oauth-token", "account_id": "acct" }
+    });
+    write_codex_live_atomic(&live_auth, Some("")).expect("seed official live auth");
+
+    let mut initial_config = MultiAppConfig::default();
+    {
+        let manager = initial_config
+            .get_manager_mut(&AppType::Codex)
+            .expect("codex manager");
+        let mut official = Provider::with_id(
+            "official-provider".to_string(),
+            "Official".to_string(),
+            json!({
+                "auth": {
+                    "auth_mode": "chatgpt",
+                    "OPENAI_API_KEY": null,
+                    "tokens": { "access_token": "official-oauth-token", "account_id": "acct" }
+                },
+                "config": ""
+            }),
+            None,
+        );
+        official.category = Some("official".to_string());
+        manager
+            .providers
+            .insert("official-provider".to_string(), official);
+    }
+    let servers = initial_config
+        .mcp
+        .servers
+        .get_or_insert_with(Default::default);
+    servers.insert(
+        "echo-server".into(),
+        McpServer {
+            id: "echo-server".into(),
+            name: "Echo Server".into(),
+            server: json!({
+                "type": "stdio",
+                "command": "echo"
+            }),
+            apps: McpApps {
+                claude: false,
+                codex: true,
+                gemini: false,
+                opencode: false,
+                hermes: false,
+            },
+            description: None,
+            homepage: None,
+            docs: None,
+            tags: Vec::new(),
+        },
+    );
+
+    let state = create_test_state_with_config(&initial_config).expect("create test state");
+
+    // 切换路径仍走 sync_all_enabled（会碰 claude），所以先切换、后破坏。
+    ProviderService::switch(&state, AppType::Codex, "official-provider")
+        .expect("switch to official provider");
+
+    // 破坏 ~/.claude.json：坏 JSON 能通过 should_sync_claude_mcp 门控
+    // （文件存在即过），但 read_mcp_servers_map 解析必然报错。
+    // 注意 codex-only 的服务器也会触发 claude 的 remove 分支读该文件。
+    let claude_json = cc_switch_lib::get_claude_mcp_path();
+    std::fs::write(&claude_json, "{ not valid json").expect("seed broken claude json");
+
+    let reapplied = cc_switch_lib::reapply_current_codex_official_live(&state)
+        .expect("MCP projection failure must degrade to a warning, not fail the toggle");
+    assert!(
+        reapplied,
+        "current provider is official, reapply should run"
+    );
+
+    // 定向投影不碰 claude：Codex 的 MCP 投影必须完成，不能被
+    // 无关应用的损坏文件阻断后静默丢失。
+    let live = std::fs::read_to_string(cc_switch_lib::get_codex_config_path())
+        .expect("read config.toml after reapply");
+    assert!(
+        live.contains("mcp_servers.echo-server"),
+        "codex MCP projection must not be blocked by a broken ~/.claude.json, got: {live}"
+    );
+
+    // 顺带锁定：定向投影不应把手改坏的 ~/.claude.json 触碰或"修复"。
+    let claude_after = std::fs::read_to_string(&claude_json).expect("read claude json");
+    assert_eq!(
+        claude_after, "{ not valid json",
+        "codex-only projection must not touch claude's live file"
+    );
+}
+
 #[test]
 fn provider_service_switch_codex_official_accounts_write_auth_json() {
     let _guard = test_mutex().lock().expect("acquire test mutex");