mark Feature::RemoteControl as removed (#22386)

## Why

`remote_control` can appear in `config.toml`, CLI feature overrides, and
the app-server config APIs. Before this PR, app-server startup treated
`config.features.enabled(Feature::RemoteControl)` as the signal to start
remote control ([base
code](https://github.com/openai/codex/blob/5e3ee5eddfa5333f2e0b011880abf0cbf92bd295/codex-rs/app-server/src/lib.rs#L678-L680)).
That meant a user with:

```toml
[features]
remote_control = true
```

would accidentally opt every app-server process into remote control.
Remote-control startup should instead be a per-process launch decision
made by CLI flags.

## What Changed

- Marks `Feature::RemoteControl` as `Stage::Removed`, keeping
`remote_control` as a known compatibility key while making it
config-inert.
- Adds a hidden `--remote-control` process flag to `codex app-server`
and standalone `codex-app-server`.
- Plumbs that flag through
`AppServerRuntimeOptions.remote_control_enabled` and makes app-server
startup use only that runtime option to decide whether to start remote
control.
- Removes the app-server config mutation hook that reloaded config and
toggled remote control at runtime.
- Updates managed daemon spawning to use `codex app-server
--remote-control --listen unix://` instead of `--enable remote_control`.

Config APIs can still list, read, write, and set `remote_control`; those
operations just no longer affect remote-control process enrollment.

codex-rs/app-server/src/in_process.rs

@@ -430,7 +430,6 @@ async fn start_uninitialized(args: InProcessStartArgs) -> IoResult<InProcessClie
                 auth_manager,
                 installation_id,
                 rpc_transport: AppServerRpcTransport::InProcess,
-                remote_control_handle: None,
                 plugin_startup_tasks: crate::PluginStartupTasks::Start,
             }));
             let mut thread_created_rx = processor.thread_created_receiver();

codex-rs/app-server/src/lib.rs

@@ -8,7 +8,6 @@ use codex_config::RemoteThreadConfigLoader;
 use codex_config::ThreadConfigLoader;
 use codex_core::config::Config;
 use codex_core::resolve_installation_id;
-use codex_features::Feature;
 use codex_login::AuthManager;
 use codex_utils_cli::CliConfigOverrides;
 use std::collections::HashMap;
@@ -392,12 +391,14 @@ pub enum PluginStartupTasks {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AppServerRuntimeOptions {
     pub plugin_startup_tasks: PluginStartupTasks,
+    pub remote_control_enabled: bool,
 }
 
 impl Default for AppServerRuntimeOptions {
     fn default() -> Self {
         Self {
             plugin_startup_tasks: PluginStartupTasks::Start,
+            remote_control_enabled: false,
         }
     }
 }
@@ -675,15 +676,15 @@ pub async fn run_main_with_transport_options(
     let auth_manager =
         AuthManager::shared_from_config(&config, /*enable_codex_api_key_env*/ false).await;
 
-    let remote_control_config_enabled = config.features.enabled(Feature::RemoteControl);
-    let remote_control_enabled = remote_control_config_enabled && state_db.is_some();
-    if remote_control_config_enabled && state_db.is_none() {
+    let remote_control_requested = runtime_options.remote_control_enabled;
+    let remote_control_enabled = remote_control_requested && state_db.is_some();
+    if remote_control_requested && state_db.is_none() {
         error!("remote control disabled because sqlite state db is unavailable");
     }
     if transport_accept_handles.is_empty() && !remote_control_enabled {
         return Err(std::io::Error::new(
             ErrorKind::InvalidInput,
-            if remote_control_config_enabled && state_db.is_none() {
+            if remote_control_requested && state_db.is_none() {
                 "no transport configured; remote control disabled because sqlite state db is unavailable"
             } else {
                 "no transport configured; use --listen or enable remote control"
@@ -787,7 +788,6 @@ pub async fn run_main_with_transport_options(
             auth_manager,
             installation_id,
             rpc_transport: analytics_rpc_transport(&transport),
-            remote_control_handle: Some(remote_control_handle.clone()),
             plugin_startup_tasks: runtime_options.plugin_startup_tasks,
         }));
         let mut thread_created_rx = processor.thread_created_receiver();

codex-rs/app-server/src/main.rs

@@ -40,6 +40,10 @@ struct AppServerArgs {
     #[cfg(debug_assertions)]
     #[arg(long = "disable-plugin-startup-tasks-for-tests", hide = true)]
     disable_plugin_startup_tasks_for_tests: bool,
+
+    /// Enable remote control for this app-server process.
+    #[arg(long = "remote-control", hide = true)]
+    remote_control: bool,
 }
 
 fn main() -> anyhow::Result<()> {
@@ -59,6 +63,7 @@ fn main() -> anyhow::Result<()> {
         if args.disable_plugin_startup_tasks_for_tests {
             runtime_options.plugin_startup_tasks = PluginStartupTasks::Skip;
         }
+        runtime_options.remote_control_enabled = args.remote_control;
 
         run_main_with_transport_options(
             arg0_paths,

codex-rs/app-server/src/message_processor.rs

@@ -42,7 +42,6 @@ use crate::skills_watcher::SkillsWatcher;
 use crate::thread_state::ConnectionCapabilities;
 use crate::thread_state::ThreadStateManager;
 use crate::transport::AppServerTransport;
-use crate::transport::RemoteControlHandle;
 use async_trait::async_trait;
 use codex_analytics::AnalyticsEventsClient;
 use codex_analytics::AppServerRpcTransport;
@@ -265,7 +264,6 @@ pub(crate) struct MessageProcessorArgs {
     pub(crate) auth_manager: Arc<AuthManager>,
     pub(crate) installation_id: String,
     pub(crate) rpc_transport: AppServerRpcTransport,
-    pub(crate) remote_control_handle: Option<RemoteControlHandle>,
     pub(crate) plugin_startup_tasks: crate::PluginStartupTasks,
 }
 
@@ -288,7 +286,6 @@ impl MessageProcessor {
             auth_manager,
             installation_id,
             rpc_transport,
-            remote_control_handle,
             plugin_startup_tasks,
         } = args;
         auth_manager.set_external_auth(Arc::new(ExternalAuthRefreshBridge {
@@ -446,7 +443,6 @@ impl MessageProcessor {
             auth_manager,
             thread_manager.clone(),
             analytics_events_client,
-            remote_control_handle,
         );
         let external_agent_config_processor = ExternalAgentConfigRequestProcessor::new(
             outgoing.clone(),

codex-rs/app-server/src/message_processor_tracing_tests.rs

@@ -264,7 +264,6 @@ async fn build_test_processor(
         auth_manager,
         installation_id: "11111111-1111-4111-8111-111111111111".to_string(),
         rpc_transport: AppServerRpcTransport::Stdio,
-        remote_control_handle: None,
         plugin_startup_tasks: crate::PluginStartupTasks::Start,
     }));
     (processor, outgoing_rx)

codex-rs/app-server/src/request_processors/config_processor.rs

@@ -6,7 +6,6 @@ use crate::error_code::internal_error;
 use crate::error_code::invalid_request;
 use crate::outgoing_message::ConnectionRequestId;
 use crate::outgoing_message::OutgoingMessageSender;
-use crate::transport::RemoteControlHandle;
 use codex_analytics::AnalyticsEventsClient;
 use codex_app_server_protocol::AppListUpdatedNotification;
 use codex_app_server_protocol::ClientResponsePayload;
@@ -39,7 +38,6 @@ use codex_config::MatcherGroup as CoreMatcherGroup;
 use codex_config::ResidencyRequirement as CoreResidencyRequirement;
 use codex_config::SandboxModeRequirement as CoreSandboxModeRequirement;
 use codex_core::ThreadManager;
-use codex_features::Feature;
 use codex_features::canonical_feature_for_key;
 use codex_features::feature_for_key;
 use codex_login::AuthManager;
@@ -67,7 +65,6 @@ pub(crate) struct ConfigRequestProcessor {
     auth_manager: Arc<AuthManager>,
     thread_manager: Arc<ThreadManager>,
     analytics_events_client: AnalyticsEventsClient,
-    remote_control_handle: Option<RemoteControlHandle>,
 }
 
 impl ConfigRequestProcessor {
@@ -77,7 +74,6 @@ impl ConfigRequestProcessor {
         auth_manager: Arc<AuthManager>,
         thread_manager: Arc<ThreadManager>,
         analytics_events_client: AnalyticsEventsClient,
-        remote_control_handle: Option<RemoteControlHandle>,
     ) -> Self {
         Self {
             outgoing,
@@ -85,7 +81,6 @@ impl ConfigRequestProcessor {
             auth_manager,
             thread_manager,
             analytics_events_client,
-            remote_control_handle,
         }
     }
 
@@ -187,21 +182,6 @@ impl ConfigRequestProcessor {
     pub(crate) async fn handle_config_mutation(&self) {
         self.thread_manager.plugins_manager().clear_cache();
         self.thread_manager.skills_manager().clear_cache();
-        let Some(remote_control_handle) = &self.remote_control_handle else {
-            return;
-        };
-
-        match self.load_latest_config(/*fallback_cwd*/ None).await {
-            Ok(config) => {
-                remote_control_handle.set_enabled(config.features.enabled(Feature::RemoteControl));
-            }
-            Err(error) => {
-                tracing::warn!(
-                    "failed to load config for remote control enablement refresh after config mutation: {}",
-                    error.message
-                );
-            }
-        }
     }
 
     async fn handle_config_mutation_result<T>(

codex-rs/app-server/src/transport.rs

@@ -18,7 +18,6 @@ pub(crate) use codex_app_server_transport::ConnectionId;
 pub(crate) use codex_app_server_transport::ConnectionOrigin;
 pub(crate) use codex_app_server_transport::OutgoingMessage;
 pub(crate) use codex_app_server_transport::QueuedOutgoingMessage;
-pub(crate) use codex_app_server_transport::RemoteControlHandle;
 pub(crate) use codex_app_server_transport::RemoteControlStartConfig;
 pub(crate) use codex_app_server_transport::TransportEvent;
 pub use codex_app_server_transport::app_server_control_socket_path;