[mcp] Improve custom MCP elicitation (#15800)

- [x] Support don't ask again for custom MCP tool calls.
- [x] Don't run arc in yolo mode.
- [x] Run arc for custom MCP tools in always allow mode.

codex-rs/app-server/tests/suite/v2/app_list.rs

@@ -1,4 +1,5 @@
 use std::borrow::Cow;
+use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::sync::Arc;
 use std::sync::Mutex as StdMutex;
@@ -27,6 +28,7 @@ use codex_app_server_protocol::AppScreenshot;
 use codex_app_server_protocol::AppsListParams;
 use codex_app_server_protocol::AppsListResponse;
 use codex_app_server_protocol::AuthMode;
+use codex_app_server_protocol::ExperimentalFeatureEnablementSetParams;
 use codex_app_server_protocol::JSONRPCError;
 use codex_app_server_protocol::JSONRPCResponse;
 use codex_app_server_protocol::RequestId;
@@ -1201,6 +1203,108 @@ async fn list_apps_force_refetch_patches_updates_from_cached_snapshots() -> Resu
     Ok(())
 }
 
+#[tokio::test]
+async fn experimental_feature_enablement_set_refreshes_apps_list_when_apps_turn_on() -> Result<()> {
+    let initial_connectors = vec![AppInfo {
+        id: "alpha".to_string(),
+        name: "Alpha".to_string(),
+        description: Some("Alpha v1".to_string()),
+        logo_url: None,
+        logo_url_dark: None,
+        distribution_channel: None,
+        branding: None,
+        app_metadata: None,
+        labels: None,
+        install_url: None,
+        is_accessible: false,
+        is_enabled: true,
+        plugin_display_names: Vec::new(),
+    }];
+    let (server_url, server_handle, server_control) = start_apps_server_with_delays_and_control(
+        initial_connectors,
+        Vec::new(),
+        Duration::ZERO,
+        Duration::ZERO,
+    )
+    .await?;
+
+    let codex_home = TempDir::new()?;
+    write_connectors_config(codex_home.path(), &server_url)?;
+    write_chatgpt_auth(
+        codex_home.path(),
+        ChatGptAuthFixture::new("chatgpt-token")
+            .account_id("account-123")
+            .chatgpt_user_id("user-enable-refresh")
+            .chatgpt_account_id("account-123"),
+        AuthCredentialsStoreMode::File,
+    )?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let disable_request = mcp
+        .send_experimental_feature_enablement_set_request(ExperimentalFeatureEnablementSetParams {
+            enablement: BTreeMap::from([("apps".to_string(), false)]),
+        })
+        .await?;
+    let _disable_response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(disable_request)),
+    )
+    .await??;
+
+    server_control.set_connectors(vec![AppInfo {
+        id: "alpha".to_string(),
+        name: "Alpha".to_string(),
+        description: Some("Alpha v2".to_string()),
+        logo_url: None,
+        logo_url_dark: None,
+        distribution_channel: None,
+        branding: None,
+        app_metadata: None,
+        labels: None,
+        install_url: None,
+        is_accessible: false,
+        is_enabled: true,
+        plugin_display_names: Vec::new(),
+    }]);
+    server_control.set_tools(vec![connector_tool("alpha", "Alpha App")?]);
+
+    let enable_request = mcp
+        .send_experimental_feature_enablement_set_request(ExperimentalFeatureEnablementSetParams {
+            enablement: BTreeMap::from([("apps".to_string(), true)]),
+        })
+        .await?;
+    let _enable_response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(enable_request)),
+    )
+    .await??;
+
+    let update = read_app_list_updated_notification(&mut mcp).await?;
+    assert_eq!(
+        update.data,
+        vec![AppInfo {
+            id: "alpha".to_string(),
+            name: "Alpha".to_string(),
+            description: Some("Alpha v2".to_string()),
+            logo_url: None,
+            logo_url_dark: None,
+            distribution_channel: None,
+            branding: None,
+            app_metadata: None,
+            labels: None,
+            install_url: Some("https://chatgpt.com/apps/alpha/alpha".to_string()),
+            is_accessible: true,
+            is_enabled: true,
+            plugin_display_names: Vec::new(),
+        }]
+    );
+
+    server_handle.abort();
+    Ok(())
+}
+
 async fn read_app_list_updated_notification(
     mcp: &mut McpProcess,
 ) -> Result<AppListUpdatedNotification> {