Remove core protocol dependency [1/2] (#20324)

## Why

This stack moves `codex-tui` away from the core protocol event surface
and toward app-server API shapes plus TUI-owned local models. This first
PR sets up the lower-risk foundation: it introduces the local model
surface and extracts app-server event routing into focused TUI modules
while preserving the existing behavior for the larger migration in PR2.

This PR is part 1 of a 2-PR stack:

1. Add TUI-owned replacement models and extract app-server event
routing.
2. Move the active TUI flow to app-server notifications and delete
obsolete adapter code.

## What changed

- Added TUI-owned approval, diff, session state, session resume, token
usage, and user-message models.
- Added `app/app_server_event_targets.rs` and `app/app_server_events.rs`
to hold app-server event targeting and dispatch logic outside `app.rs`.
- Updated app/status tests to use the local model layer and added
focused routing coverage.
- Boxed a few large async TUI test futures so this base layer remains
checkable without overflowing the default test stack.

## Verification

- `cargo check -p codex-tui --tests`

codex-rs/tui/src/app/app_server_event_targets.rs

@@ -0,0 +1,218 @@
+//! Thread targeting helpers for app-server requests and notifications.
+
+use codex_app_server_protocol::ServerNotification;
+use codex_app_server_protocol::ServerRequest;
+use codex_protocol::ThreadId;
+
+pub(super) fn server_request_thread_id(request: &ServerRequest) -> Option<ThreadId> {
+    match request {
+        ServerRequest::CommandExecutionRequestApproval { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::FileChangeRequestApproval { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::ToolRequestUserInput { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::McpServerElicitationRequest { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::PermissionsRequestApproval { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::DynamicToolCall { params, .. } => {
+            ThreadId::from_string(&params.thread_id).ok()
+        }
+        ServerRequest::ChatgptAuthTokensRefresh { .. }
+        | ServerRequest::ApplyPatchApproval { .. }
+        | ServerRequest::ExecCommandApproval { .. } => None,
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub(super) enum ServerNotificationThreadTarget {
+    Thread(ThreadId),
+    InvalidThreadId(String),
+    Global,
+}
+
+pub(super) fn server_notification_thread_target(
+    notification: &ServerNotification,
+) -> ServerNotificationThreadTarget {
+    let thread_id = match notification {
+        ServerNotification::Error(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ThreadStarted(notification) => Some(notification.thread.id.as_str()),
+        ServerNotification::ThreadStatusChanged(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadArchived(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ThreadUnarchived(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ThreadClosed(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ThreadNameUpdated(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadTokenUsageUpdated(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadGoalUpdated(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadGoalCleared(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::TurnStarted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::HookStarted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::TurnCompleted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::HookCompleted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::TurnDiffUpdated(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::TurnPlanUpdated(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ItemStarted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ItemGuardianApprovalReviewStarted(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ItemGuardianApprovalReviewCompleted(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ItemCompleted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::RawResponseItemCompleted(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::AgentMessageDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::PlanDelta(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::CommandExecutionOutputDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::TerminalInteraction(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::FileChangeOutputDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::FileChangePatchUpdated(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ServerRequestResolved(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::McpToolCallProgress(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ReasoningSummaryTextDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ReasoningSummaryPartAdded(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ReasoningTextDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ContextCompacted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ModelRerouted(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::ModelVerification(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeStarted(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeItemAdded(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeTranscriptDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeTranscriptDone(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeOutputAudioDelta(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeSdp(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeError(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::ThreadRealtimeClosed(notification) => {
+            Some(notification.thread_id.as_str())
+        }
+        ServerNotification::Warning(notification) => notification.thread_id.as_deref(),
+        ServerNotification::GuardianWarning(notification) => Some(notification.thread_id.as_str()),
+        ServerNotification::SkillsChanged(_)
+        | ServerNotification::McpServerStatusUpdated(_)
+        | ServerNotification::McpServerOauthLoginCompleted(_)
+        | ServerNotification::AccountUpdated(_)
+        | ServerNotification::AccountRateLimitsUpdated(_)
+        | ServerNotification::AppListUpdated(_)
+        | ServerNotification::RemoteControlStatusChanged(_)
+        | ServerNotification::ExternalAgentConfigImportCompleted(_)
+        | ServerNotification::DeprecationNotice(_)
+        | ServerNotification::ConfigWarning(_)
+        | ServerNotification::FuzzyFileSearchSessionUpdated(_)
+        | ServerNotification::FuzzyFileSearchSessionCompleted(_)
+        | ServerNotification::CommandExecOutputDelta(_)
+        | ServerNotification::FsChanged(_)
+        | ServerNotification::WindowsWorldWritableWarning(_)
+        | ServerNotification::WindowsSandboxSetupCompleted(_)
+        | ServerNotification::AccountLoginCompleted(_) => None,
+    };
+
+    match thread_id {
+        Some(thread_id) => match ThreadId::from_string(thread_id) {
+            Ok(thread_id) => ServerNotificationThreadTarget::Thread(thread_id),
+            Err(_) => ServerNotificationThreadTarget::InvalidThreadId(thread_id.to_string()),
+        },
+        None => ServerNotificationThreadTarget::Global,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::ServerNotificationThreadTarget;
+    use super::server_notification_thread_target;
+    use codex_app_server_protocol::GuardianWarningNotification;
+    use codex_app_server_protocol::ServerNotification;
+    use codex_app_server_protocol::WarningNotification;
+    use codex_protocol::ThreadId;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn warning_notifications_without_threads_are_global() {
+        let notification = ServerNotification::Warning(WarningNotification {
+            thread_id: None,
+            message: "warning".to_string(),
+        });
+
+        let target = server_notification_thread_target(&notification);
+
+        assert_eq!(target, ServerNotificationThreadTarget::Global);
+    }
+
+    #[test]
+    fn warning_notifications_route_to_threads_when_thread_id_is_present() {
+        let thread_id = ThreadId::new();
+        let notification = ServerNotification::Warning(WarningNotification {
+            thread_id: Some(thread_id.to_string()),
+            message: "warning".to_string(),
+        });
+
+        let target = server_notification_thread_target(&notification);
+
+        assert_eq!(target, ServerNotificationThreadTarget::Thread(thread_id));
+    }
+
+    #[test]
+    fn guardian_warning_notifications_route_to_threads() {
+        let thread_id = ThreadId::new();
+        let notification = ServerNotification::GuardianWarning(GuardianWarningNotification {
+            thread_id: thread_id.to_string(),
+            message: "warning".to_string(),
+        });
+
+        let target = server_notification_thread_target(&notification);
+
+        assert_eq!(target, ServerNotificationThreadTarget::Thread(thread_id));
+    }
+}

codex-rs/tui/src/app/app_server_events.rs

@@ -0,0 +1,208 @@
+//! App-server event stream handling for the TUI app.
+
+use super::App;
+use super::app_server_event_targets::ServerNotificationThreadTarget;
+use super::app_server_event_targets::server_notification_thread_target;
+use super::app_server_event_targets::server_request_thread_id;
+use crate::app_command::AppCommand;
+use crate::app_event::AppEvent;
+use crate::app_server_session::AppServerSession;
+use crate::app_server_session::app_server_rate_limit_snapshot_to_core;
+use crate::app_server_session::status_account_display_from_auth_mode;
+use codex_app_server_client::AppServerEvent;
+use codex_app_server_protocol::AuthMode;
+use codex_app_server_protocol::JSONRPCErrorError;
+use codex_app_server_protocol::ServerNotification;
+use codex_app_server_protocol::ServerRequest;
+
+impl App {
+    fn refresh_mcp_startup_expected_servers_from_config(&mut self) {
+        let enabled_config_mcp_servers: Vec<String> = self
+            .chat_widget
+            .config_ref()
+            .mcp_servers
+            .get()
+            .iter()
+            .filter_map(|(name, server)| server.enabled.then_some(name.clone()))
+            .collect();
+        self.chat_widget
+            .set_mcp_startup_expected_servers(enabled_config_mcp_servers);
+    }
+
+    pub(super) async fn handle_app_server_event(
+        &mut self,
+        app_server_client: &AppServerSession,
+        event: AppServerEvent,
+    ) {
+        match event {
+            AppServerEvent::Lagged { skipped } => {
+                tracing::warn!(
+                    skipped,
+                    "app-server event consumer lagged; dropping ignored events"
+                );
+                self.refresh_mcp_startup_expected_servers_from_config();
+                self.chat_widget.finish_mcp_startup_after_lag();
+            }
+            AppServerEvent::ServerNotification(notification) => {
+                self.handle_server_notification_event(app_server_client, notification)
+                    .await;
+            }
+            AppServerEvent::ServerRequest(request) => {
+                self.handle_server_request_event(app_server_client, request)
+                    .await;
+            }
+            AppServerEvent::Disconnected { message } => {
+                tracing::warn!("app-server event stream disconnected: {message}");
+                self.chat_widget.add_error_message(message.clone());
+                self.app_event_tx.send(AppEvent::FatalExitRequest(message));
+            }
+        }
+    }
+
+    async fn handle_server_notification_event(
+        &mut self,
+        app_server_client: &AppServerSession,
+        notification: ServerNotification,
+    ) {
+        match &notification {
+            ServerNotification::ServerRequestResolved(notification) => {
+                if let Some(request) = self
+                    .pending_app_server_requests
+                    .resolve_notification(&notification.request_id)
+                {
+                    self.chat_widget.dismiss_app_server_request(&request);
+                }
+            }
+            ServerNotification::McpServerStatusUpdated(_) => {
+                self.refresh_mcp_startup_expected_servers_from_config();
+            }
+            ServerNotification::AccountRateLimitsUpdated(notification) => {
+                self.chat_widget.on_rate_limit_snapshot(Some(
+                    app_server_rate_limit_snapshot_to_core(notification.rate_limits.clone()),
+                ));
+                return;
+            }
+            ServerNotification::AccountUpdated(notification) => {
+                self.chat_widget.update_account_state(
+                    status_account_display_from_auth_mode(
+                        notification.auth_mode,
+                        notification.plan_type,
+                    ),
+                    notification.plan_type,
+                    matches!(
+                        notification.auth_mode,
+                        Some(AuthMode::Chatgpt) | Some(AuthMode::ChatgptAuthTokens)
+                    ),
+                );
+                return;
+            }
+            ServerNotification::ExternalAgentConfigImportCompleted(_) => {
+                let cwd = self.chat_widget.config_ref().cwd.to_path_buf();
+                if let Err(err) = self.refresh_in_memory_config_from_disk().await {
+                    tracing::warn!(
+                        error = %err,
+                        "failed to refresh config after external agent config import"
+                    );
+                }
+                self.chat_widget.refresh_plugin_mentions();
+                self.chat_widget.submit_op(AppCommand::reload_user_config());
+                self.fetch_plugins_list(app_server_client, cwd);
+                return;
+            }
+            _ => {}
+        }
+
+        match server_notification_thread_target(&notification) {
+            ServerNotificationThreadTarget::Thread(thread_id) => {
+                let result = if self.primary_thread_id == Some(thread_id)
+                    || self.primary_thread_id.is_none()
+                {
+                    self.enqueue_primary_thread_notification(notification).await
+                } else {
+                    self.enqueue_thread_notification(thread_id, notification)
+                        .await
+                };
+
+                if let Err(err) = result {
+                    tracing::warn!("failed to enqueue app-server notification: {err}");
+                }
+                return;
+            }
+            ServerNotificationThreadTarget::InvalidThreadId(thread_id) => {
+                tracing::warn!(
+                    thread_id,
+                    "ignoring app-server notification with invalid thread_id"
+                );
+                return;
+            }
+            ServerNotificationThreadTarget::Global => {}
+        }
+
+        self.chat_widget
+            .handle_server_notification(notification, /*replay_kind*/ None);
+    }
+
+    async fn handle_server_request_event(
+        &mut self,
+        app_server_client: &AppServerSession,
+        request: ServerRequest,
+    ) {
+        if let Some(unsupported) = self
+            .pending_app_server_requests
+            .note_server_request(&request)
+        {
+            tracing::warn!(
+                request_id = ?unsupported.request_id,
+                message = unsupported.message,
+                "rejecting unsupported app-server request"
+            );
+            self.chat_widget
+                .add_error_message(unsupported.message.clone());
+            if let Err(err) = self
+                .reject_app_server_request(
+                    app_server_client,
+                    unsupported.request_id,
+                    unsupported.message,
+                )
+                .await
+            {
+                tracing::warn!("{err}");
+            }
+            return;
+        }
+
+        let Some(thread_id) = server_request_thread_id(&request) else {
+            tracing::warn!("ignoring threadless app-server request");
+            return;
+        };
+
+        let result =
+            if self.primary_thread_id == Some(thread_id) || self.primary_thread_id.is_none() {
+                self.enqueue_primary_thread_request(request).await
+            } else {
+                self.enqueue_thread_request(thread_id, request).await
+            };
+        if let Err(err) = result {
+            tracing::warn!("failed to enqueue app-server request: {err}");
+        }
+    }
+
+    async fn reject_app_server_request(
+        &self,
+        app_server_client: &AppServerSession,
+        request_id: codex_app_server_protocol::RequestId,
+        reason: String,
+    ) -> std::result::Result<(), String> {
+        app_server_client
+            .reject_server_request(
+                request_id,
+                JSONRPCErrorError {
+                    code: -32000,
+                    message: reason,
+                    data: None,
+                },
+            )
+            .await
+            .map_err(|err| format!("failed to reject app-server request: {err}"))
+    }
+}

codex-rs/tui/src/app/tests.rs

@@ -1227,15 +1227,17 @@ async fn token_usage_update_refreshes_status_line_with_runtime_context_window()
 
 #[tokio::test]
 async fn open_agent_picker_keeps_missing_threads_for_replay() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.thread_event_channels
         .insert(thread_id, ThreadEventChannel::new(/*capacity*/ 1));
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
 
     assert_eq!(app.thread_event_channels.contains_key(&thread_id), true);
     assert_eq!(
@@ -1252,10 +1254,12 @@ async fn open_agent_picker_keeps_missing_threads_for_replay() -> Result<()> {
 
 #[tokio::test]
 async fn open_agent_picker_preserves_cached_metadata_for_replay_threads() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.thread_event_channels
         .insert(thread_id, ThreadEventChannel::new(/*capacity*/ 1));
@@ -1266,7 +1270,7 @@ async fn open_agent_picker_preserves_cached_metadata_for_replay_threads() -> Res
         /*is_closed*/ true,
     );
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
 
     assert_eq!(app.thread_event_channels.contains_key(&thread_id), true);
     assert_eq!(
@@ -1282,10 +1286,12 @@ async fn open_agent_picker_preserves_cached_metadata_for_replay_threads() -> Res
 
 #[tokio::test]
 async fn open_agent_picker_prunes_terminal_metadata_only_threads() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.agent_navigation.upsert(
         thread_id,
@@ -1294,7 +1300,7 @@ async fn open_agent_picker_prunes_terminal_metadata_only_threads() -> Result<()>
         /*is_closed*/ false,
     );
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
 
     assert_eq!(app.agent_navigation.get(&thread_id), None);
     assert!(app.agent_navigation.is_empty());
@@ -1303,10 +1309,12 @@ async fn open_agent_picker_prunes_terminal_metadata_only_threads() -> Result<()>
 
 #[tokio::test]
 async fn open_agent_picker_marks_terminal_read_errors_closed() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.thread_event_channels
         .insert(thread_id, ThreadEventChannel::new(/*capacity*/ 1));
@@ -1317,7 +1325,7 @@ async fn open_agent_picker_marks_terminal_read_errors_closed() -> Result<()> {
         /*is_closed*/ false,
     );
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
 
     assert_eq!(
         app.agent_navigation.get(&thread_id),
@@ -1332,10 +1340,12 @@ async fn open_agent_picker_marks_terminal_read_errors_closed() -> Result<()> {
 
 #[tokio::test]
 async fn open_agent_picker_marks_loaded_threads_open() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let started = app_server
         .start_thread(app.chat_widget.config_ref())
         .await?;
@@ -1343,7 +1353,7 @@ async fn open_agent_picker_marks_loaded_threads_open() -> Result<()> {
     app.thread_event_channels
         .insert(thread_id, ThreadEventChannel::new(/*capacity*/ 1));
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
 
     assert_eq!(
         app.agent_navigation.get(&thread_id),
@@ -1356,65 +1366,87 @@ async fn open_agent_picker_marks_loaded_threads_open() -> Result<()> {
     Ok(())
 }
 
-#[tokio::test]
-async fn attach_live_thread_for_selection_rejects_empty_non_ephemeral_fallback_threads()
--> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
-    let started = app_server
-        .start_thread(app.chat_widget.config_ref())
-        .await?;
-    let thread_id = started.session.thread_id;
-    app.agent_navigation.upsert(
-        thread_id,
-        Some("Scout".to_string()),
-        Some("worker".to_string()),
-        /*is_closed*/ false,
-    );
+#[test]
+fn attach_live_thread_for_selection_rejects_empty_non_ephemeral_fallback_threads() -> Result<()> {
+    const WORKER_THREADS: usize = 1;
+    const TEST_STACK_SIZE_BYTES: usize = 8 * 1024 * 1024;
 
-    let err = app
-        .attach_live_thread_for_selection(&mut app_server, thread_id)
-        .await
-        .expect_err("empty fallback should not attach as a blank replay-only thread");
+    let runtime = tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(WORKER_THREADS)
+        .thread_stack_size(TEST_STACK_SIZE_BYTES)
+        .enable_all()
+        .build()?;
 
-    assert_eq!(
-        err.to_string(),
-        format!("Agent thread {thread_id} is not yet available for replay or live attach.")
-    );
-    assert!(!app.thread_event_channels.contains_key(&thread_id));
-    Ok(())
+    runtime.block_on(async {
+        let config = {
+            let app = make_test_app().await;
+            app.chat_widget.config_ref().clone()
+        };
+        let mut app_server = crate::start_embedded_app_server_for_picker(&config)
+            .await
+            .expect("embedded app server");
+        let started = app_server.start_thread(&config).await?;
+        let thread_id = started.session.thread_id;
+        let mut app = make_test_app().await;
+        app.agent_navigation.upsert(
+            thread_id,
+            Some("Scout".to_string()),
+            Some("worker".to_string()),
+            /*is_closed*/ false,
+        );
+
+        let err = app
+            .attach_live_thread_for_selection(&mut app_server, thread_id)
+            .await
+            .expect_err("empty fallback should not attach as a blank replay-only thread");
+
+        assert_eq!(
+            err.to_string(),
+            format!("Agent thread {thread_id} is not yet available for replay or live attach.")
+        );
+        assert!(!app.thread_event_channels.contains_key(&thread_id));
+        Ok(())
+    })
 }
 
-#[tokio::test]
-async fn attach_live_thread_for_selection_rejects_unmaterialized_fallback_threads() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
-    let mut ephemeral_config = app.chat_widget.config_ref().clone();
-    ephemeral_config.ephemeral = true;
-    let started = app_server.start_thread(&ephemeral_config).await?;
-    let thread_id = started.session.thread_id;
-    app.agent_navigation.upsert(
-        thread_id,
-        Some("Scout".to_string()),
-        Some("worker".to_string()),
-        /*is_closed*/ false,
-    );
+#[test]
+fn attach_live_thread_for_selection_rejects_unmaterialized_fallback_threads() -> Result<()> {
+    const WORKER_THREADS: usize = 1;
+    const TEST_STACK_SIZE_BYTES: usize = 8 * 1024 * 1024;
 
-    let err = app
-        .attach_live_thread_for_selection(&mut app_server, thread_id)
-        .await
-        .expect_err("ephemeral fallback should not attach as a blank live thread");
+    let runtime = tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(WORKER_THREADS)
+        .thread_stack_size(TEST_STACK_SIZE_BYTES)
+        .enable_all()
+        .build()?;
 
-    assert_eq!(
-        err.to_string(),
-        format!("Agent thread {thread_id} is not yet available for replay or live attach.")
-    );
-    assert!(!app.thread_event_channels.contains_key(&thread_id));
-    Ok(())
+    runtime.block_on(async {
+        let mut app = make_test_app().await;
+        let mut app_server =
+            crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref()).await?;
+        let mut ephemeral_config = app.chat_widget.config_ref().clone();
+        ephemeral_config.ephemeral = true;
+        let started = app_server.start_thread(&ephemeral_config).await?;
+        let thread_id = started.session.thread_id;
+        app.agent_navigation.upsert(
+            thread_id,
+            Some("Scout".to_string()),
+            Some("worker".to_string()),
+            /*is_closed*/ false,
+        );
+
+        let err = app
+            .attach_live_thread_for_selection(&mut app_server, thread_id)
+            .await
+            .expect_err("ephemeral fallback should not attach as a blank live thread");
+
+        assert_eq!(
+            err.to_string(),
+            format!("Agent thread {thread_id} is not yet available for replay or live attach.")
+        );
+        assert!(!app.thread_event_channels.contains_key(&thread_id));
+        Ok(())
+    })
 }
 
 #[tokio::test]
@@ -1445,10 +1477,12 @@ async fn should_attach_live_thread_for_selection_skips_closed_metadata_only_thre
 
 #[tokio::test]
 async fn refresh_agent_picker_thread_liveness_prunes_closed_metadata_only_threads() -> Result<()> {
-    let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app = Box::pin(make_test_app()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.agent_navigation.upsert(
         thread_id,
@@ -1457,9 +1491,8 @@ async fn refresh_agent_picker_thread_liveness_prunes_closed_metadata_only_thread
         /*is_closed*/ false,
     );
 
-    let is_available = app
-        .refresh_agent_picker_thread_liveness(&mut app_server, thread_id)
-        .await;
+    let is_available =
+        Box::pin(app.refresh_agent_picker_thread_liveness(&mut app_server, thread_id)).await;
 
     assert!(!is_available);
     assert_eq!(app.agent_navigation.get(&thread_id), None);
@@ -1469,13 +1502,15 @@ async fn refresh_agent_picker_thread_liveness_prunes_closed_metadata_only_thread
 
 #[tokio::test]
 async fn open_agent_picker_prompts_to_enable_multi_agent_when_disabled() -> Result<()> {
-    let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let (mut app, mut app_event_rx, _op_rx) = Box::pin(make_test_app_with_channels()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let _ = app.config.features.disable(Feature::Collab);
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
     app.chat_widget
         .handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
 
@@ -1499,16 +1534,16 @@ async fn open_agent_picker_prompts_to_enable_multi_agent_when_disabled() -> Resu
 
 #[tokio::test]
 async fn update_memory_settings_persists_and_updates_widget_config() -> Result<()> {
-    let (mut app, _app_event_rx, _op_rx) = make_test_app_with_channels().await;
+    let (mut app, _app_event_rx, _op_rx) = Box::pin(make_test_app_with_channels()).await;
     let codex_home = tempdir()?;
     app.config.codex_home = codex_home.path().to_path_buf().abs();
-    let mut app_server = crate::start_embedded_app_server_for_picker(&app.config).await?;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(&app.config)).await?;
 
-    app.update_memory_settings_with_app_server(
+    Box::pin(app.update_memory_settings_with_app_server(
         &mut app_server,
         /*use_memories*/ false,
         /*generate_memories*/ false,
-    )
+    ))
     .await;
 
     assert!(!app.config.memories.use_memories);
@@ -1542,22 +1577,22 @@ async fn update_memory_settings_persists_and_updates_widget_config() -> Result<(
 
 #[tokio::test]
 async fn update_memory_settings_updates_current_thread_memory_mode() -> Result<()> {
-    let (mut app, _app_event_rx, _op_rx) = make_test_app_with_channels().await;
+    let (mut app, _app_event_rx, _op_rx) = Box::pin(make_test_app_with_channels()).await;
     let codex_home = tempdir()?;
     app.config.codex_home = codex_home.path().to_path_buf().abs();
     // Seed the previous setting so this test exercises the thread-mode update path.
     app.config.memories.generate_memories = true;
 
-    let mut app_server = crate::start_embedded_app_server_for_picker(&app.config).await?;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(&app.config)).await?;
     let started = app_server.start_thread(&app.config).await?;
     let thread_id = started.session.thread_id;
     app.active_thread_id = Some(thread_id);
 
-    app.update_memory_settings_with_app_server(
+    Box::pin(app.update_memory_settings_with_app_server(
         &mut app_server,
         /*use_memories*/ true,
         /*generate_memories*/ false,
-    )
+    ))
     .await;
 
     let state_db = codex_state::StateRuntime::init(
@@ -1578,7 +1613,7 @@ async fn update_memory_settings_updates_current_thread_memory_mode() -> Result<(
 
 #[tokio::test]
 async fn reset_memories_clears_local_memory_directories() -> Result<()> {
-    let (mut app, _app_event_rx, _op_rx) = make_test_app_with_channels().await;
+    let (mut app, _app_event_rx, _op_rx) = Box::pin(make_test_app_with_channels()).await;
     let codex_home = tempdir()?;
     app.config.codex_home = codex_home.path().to_path_buf().abs();
     app.config.sqlite_home = codex_home.path().to_path_buf();
@@ -1594,9 +1629,9 @@ async fn reset_memories_clears_local_memory_directories() -> Result<()> {
     )?;
     std::fs::write(extensions_root.join("stale.txt"), "stale extension\n")?;
 
-    let mut app_server = crate::start_embedded_app_server_for_picker(&app.config).await?;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(&app.config)).await?;
 
-    app.reset_memories_with_app_server(&mut app_server).await;
+    Box::pin(app.reset_memories_with_app_server(&mut app_server)).await;
 
     assert_eq!(std::fs::read_dir(&memory_root)?.count(), 0);
 
@@ -2138,15 +2173,17 @@ async fn update_feature_flags_disabling_guardian_in_profile_keeps_inherited_non_
 
 #[tokio::test]
 async fn open_agent_picker_allows_existing_agent_threads_when_feature_is_disabled() -> Result<()> {
-    let (mut app, mut app_event_rx, _op_rx) = make_test_app_with_channels().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let (mut app, mut app_event_rx, _op_rx) = Box::pin(make_test_app_with_channels()).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let thread_id = ThreadId::new();
     app.thread_event_channels
         .insert(thread_id, ThreadEventChannel::new(/*capacity*/ 1));
 
-    app.open_agent_picker(&mut app_server).await;
+    Box::pin(app.open_agent_picker(&mut app_server)).await;
     app.chat_widget
         .handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
 
@@ -4856,7 +4893,7 @@ async fn thread_rollback_response_discards_queued_active_thread_events() {
 
 #[tokio::test]
 async fn new_session_requests_shutdown_for_previous_conversation() {
-    let (mut app, mut app_event_rx, mut op_rx) = make_test_app_with_channels().await;
+    let (mut app, mut app_event_rx, mut op_rx) = Box::pin(make_test_app_with_channels()).await;
 
     let thread_id = ThreadId::new();
     let event = SessionConfiguredEvent {
@@ -4887,10 +4924,12 @@ async fn new_session_requests_shutdown_for_previous_conversation() {
     while app_event_rx.try_recv().is_ok() {}
     while op_rx.try_recv().is_ok() {}
 
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
-    app.shutdown_current_thread(&mut app_server).await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
+    Box::pin(app.shutdown_current_thread(&mut app_server)).await;
 
     assert!(
         op_rx.try_recv().is_err(),
@@ -4904,12 +4943,12 @@ async fn shutdown_first_exit_returns_immediate_exit_when_shutdown_submit_fails()
     let thread_id = ThreadId::new();
     app.active_thread_id = Some(thread_id);
 
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
-    let control = app
-        .handle_exit_mode(&mut app_server, ExitMode::ShutdownFirst)
-        .await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
+    let control = Box::pin(app.handle_exit_mode(&mut app_server, ExitMode::ShutdownFirst)).await;
 
     assert_eq!(app.pending_shutdown_exit_thread_id, None);
     assert!(matches!(
@@ -4920,16 +4959,16 @@ async fn shutdown_first_exit_returns_immediate_exit_when_shutdown_submit_fails()
 
 #[tokio::test]
 async fn shutdown_first_exit_uses_app_server_shutdown_without_submitting_op() {
-    let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;
+    let (mut app, _app_event_rx, mut op_rx) = Box::pin(make_test_app_with_channels()).await;
     let thread_id = ThreadId::new();
     app.active_thread_id = Some(thread_id);
 
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
-    let control = app
-        .handle_exit_mode(&mut app_server, ExitMode::ShutdownFirst)
-        .await;
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
+    let control = Box::pin(app.handle_exit_mode(&mut app_server, ExitMode::ShutdownFirst)).await;
 
     assert_eq!(app.pending_shutdown_exit_thread_id, None);
     assert!(matches!(
@@ -4945,9 +4984,11 @@ async fn shutdown_first_exit_uses_app_server_shutdown_without_submitting_op() {
 #[tokio::test]
 async fn interrupt_without_active_turn_is_treated_as_handled() {
     let mut app = make_test_app().await;
-    let mut app_server = crate::start_embedded_app_server_for_picker(app.chat_widget.config_ref())
-        .await
-        .expect("embedded app server");
+    let mut app_server = Box::pin(crate::start_embedded_app_server_for_picker(
+        app.chat_widget.config_ref(),
+    ))
+    .await
+    .expect("embedded app server");
     let started = app_server
         .start_thread(app.chat_widget.config_ref())
         .await
@@ -4958,10 +4999,10 @@ async fn interrupt_without_active_turn_is_treated_as_handled() {
         .expect("primary thread should be registered");
     let op = AppCommand::interrupt();
 
-    let handled = app
-        .try_submit_active_thread_op_via_app_server(&mut app_server, thread_id, &op)
-        .await
-        .expect("interrupt submission should not fail");
+    let handled =
+        Box::pin(app.try_submit_active_thread_op_via_app_server(&mut app_server, thread_id, &op))
+            .await
+            .expect("interrupt submission should not fail");
 
     assert_eq!(handled, true);
 }