From a2de8fedcc3abe3cdde09b43515db820fb6b95b5 Mon Sep 17 00:00:00 2001
From: Eric Traut <etraut@openai.com>
Date: Sun, 20 Sep 2026 16:44:23 +0000
Subject: [PATCH] Move fullscreen transcript control to TUI configuration
 (#46849)

## What changed

Use `tui.fullscreen_transcript` to opt into the fullscreen transcript, including scrolling, selection, and search. It defaults to `false`; `--no-alt-screen` and `tui.alternate_screen = "never"` still take precedence.

The new preference controls both the first frame and application startup. Boolean CLI overrides for it are allowed during daemon startup. The old `features.transcript_v2` flag is deprecated and ignored, with a notice directing users to the new setting; it does not migrate into or override the preference.

## Testing

Add coverage for default terminal scrollback, fullscreen persistence through startup, alternate-screen restrictions, daemon override validation, and independence from the deprecated flag. Update existing history and activity tests to use the new preference.

GitOrigin-RevId: 4117bf1ee548fa8d101a594f9506673d87c74c15
---
 codex-rs/cli/tests/features.rs                |  2 +-
 codex-rs/config/src/types.rs                  |  5 ++++
 codex-rs/core/config.schema.json              |  5 ++++
 codex-rs/core/src/config/config_tests.rs      |  2 ++
 codex-rs/core/src/config/mod.rs               |  7 +++++
 codex-rs/features/src/lib.rs                  | 12 ++++++--
 codex-rs/features/src/tests.rs                |  9 ------
 codex-rs/thread-manager-sample/src/main.rs    |  1 +
 codex-rs/tui/src/app/startup.rs               |  2 +-
 .../src/app/tests/history_hydration_tests.rs  |  4 +--
 .../src/app_server_session/history_tests.rs   | 11 ++-----
 .../tests/dynamic_activity_tests.rs           | 10 ++-----
 codex-rs/tui/src/daemon_startup.rs            |  5 +++-
 codex-rs/tui/src/daemon_startup_tests.rs      |  6 ++++
 codex-rs/tui/src/lib.rs                       |  2 +-
 codex-rs/tui/src/local_settings.rs            |  4 +--
 codex-rs/tui/src/local_settings_tests.rs      | 27 +++++++++++++++--
 codex-rs/tui/src/startup_presentation.rs      | 29 +++----------------
 .../tui/src/startup_presentation_tests.rs     |  9 +++---
 codex-rs/tui/tests/suite/focus_palette.rs     | 29 +++++++++++++++----
 20 files changed, 106 insertions(+), 75 deletions(-)

diff --git a/codex-rs/cli/tests/features.rs b/codex-rs/cli/tests/features.rs
index 6a0c5603fc..4beebb0d3f 100644
--- a/codex-rs/cli/tests/features.rs
+++ b/codex-rs/cli/tests/features.rs
@@ -133,7 +133,7 @@ fn strict_config_is_not_supported_for_cloud_command() -> Result<()> {
 async fn features_enable_writes_feature_flag_to_config() -> Result<()> {
     let codex_home = TempDir::new()?;
 
-    for feature in ["unified_exec", "transcript_v2"] {
+    for feature in ["unified_exec", "shell_tool"] {
         let mut cmd = codex_command(codex_home.path())?;
         cmd.args(["features", "enable", feature])
             .assert()
diff --git a/codex-rs/config/src/types.rs b/codex-rs/config/src/types.rs
index fc77dc0495..a03851e4d5 100644
--- a/codex-rs/config/src/types.rs
+++ b/codex-rs/config/src/types.rs
@@ -793,6 +793,11 @@ pub struct Tui {
     #[serde(default)]
     pub raw_output_mode: bool,
 
+    /// Own the fullscreen transcript, including scrolling, selection, and search.
+    /// Defaults to `false`; alternate-screen restrictions take precedence.
+    #[serde(default)]
+    pub fullscreen_transcript: bool,
+
     /// Controls whether the TUI uses the terminal's alternate screen buffer.
     ///
     /// - `auto` (default): Use alternate screen.
diff --git a/codex-rs/core/config.schema.json b/codex-rs/core/config.schema.json
index 90b8c944e9..f3138968a7 100644
--- a/codex-rs/core/config.schema.json
+++ b/codex-rs/core/config.schema.json
@@ -4226,6 +4226,11 @@
           },
           "description": "Individual visual effects. Each also requires animations to be enabled."
         },
+        "fullscreen_transcript": {
+          "default": false,
+          "description": "Own the fullscreen transcript, including scrolling, selection, and search. Defaults to `false`; alternate-screen restrictions take precedence.",
+          "type": "boolean"
+        },
         "keymap": {
           "allOf": [
             {
diff --git a/codex-rs/core/src/config/config_tests.rs b/codex-rs/core/src/config/config_tests.rs
index b4277cd2cc..4af6772d10 100644
--- a/codex-rs/core/src/config/config_tests.rs
+++ b/codex-rs/core/src/config/config_tests.rs
@@ -1261,6 +1261,7 @@ fn config_toml_deserializes_model_availability_nux() {
             vim_mode_default: false,
             question_esc_back: true,
             raw_output_mode: false,
+            fullscreen_transcript: false,
             alternate_screen: AltScreenMode::default(),
             status_line: None,
             status_line_use_colors: true,
@@ -4388,6 +4389,7 @@ fn tui_config_missing_notifications_field_defaults_to_enabled() {
             vim_mode_default: false,
             question_esc_back: true,
             raw_output_mode: false,
+            fullscreen_transcript: false,
             alternate_screen: AltScreenMode::Auto,
             status_line: None,
             status_line_use_colors: true,
diff --git a/codex-rs/core/src/config/mod.rs b/codex-rs/core/src/config/mod.rs
index 2bc67b91b5..7b6ec2d393 100644
--- a/codex-rs/core/src/config/mod.rs
+++ b/codex-rs/core/src/config/mod.rs
@@ -770,6 +770,9 @@ pub struct Config {
     /// Start the TUI in raw scrollback mode for copy-friendly transcript output.
     pub tui_raw_output_mode: bool,
 
+    /// Own the fullscreen transcript when the alternate screen is enabled.
+    pub tui_fullscreen_transcript: bool,
+
     /// Start the TUI in the specified collaboration mode (plan/default).
 
     /// Controls whether the TUI uses the terminal's alternate screen buffer.
@@ -4406,6 +4409,10 @@ impl Config {
                 .as_ref()
                 .map(|t| t.raw_output_mode)
                 .unwrap_or(false),
+            tui_fullscreen_transcript: cfg
+                .tui
+                .as_ref()
+                .is_some_and(|tui| tui.fullscreen_transcript),
             tui_alternate_screen: cfg
                 .tui
                 .as_ref()
diff --git a/codex-rs/features/src/lib.rs b/codex-rs/features/src/lib.rs
index 83337a6c89..ad635f05e9 100644
--- a/codex-rs/features/src/lib.rs
+++ b/codex-rs/features/src/lib.rs
@@ -95,7 +95,7 @@ pub enum Feature {
     AnalyticsPlanHistory,
     /// Discover model catalogs for OpenAI API-key authentication.
     ApiKeyModelDiscovery,
-    /// Enable the interactive transcript composer and turn-selection UI.
+    /// Deprecated no-op; use `tui.fullscreen_transcript` instead.
     TranscriptV2,
     // Stable.
     /// Enable the default shell tool.
@@ -592,6 +592,10 @@ impl Features {
                         Feature::WebSearchCached,
                     );
                 }
+                "transcript_v2" => {
+                    self.record_legacy_usage_force("features.transcript_v2", Feature::TranscriptV2);
+                    continue;
+                }
                 "tui_app_server" => {
                     continue;
                 }
@@ -696,6 +700,10 @@ impl Features {
 fn legacy_usage_notice(alias: &str, feature: Feature) -> (String, Option<String>) {
     let canonical = feature.key();
     match feature {
+        Feature::TranscriptV2 => (
+            "`[features].transcript_v2` is deprecated and ignored.".to_string(),
+            Some("Use `[tui].fullscreen_transcript` in config.toml instead.".to_string()),
+        ),
         Feature::WebSearchRequest | Feature::WebSearchCached => {
             let label = match alias {
                 "web_search" => "[features].web_search",
@@ -937,7 +945,7 @@ pub const FEATURES: &[FeatureSpec] = &[
     FeatureSpec {
         id: Feature::TranscriptV2,
         key: "transcript_v2",
-        stage: Stage::UnderDevelopment,
+        stage: Stage::Deprecated,
         default_enabled: false,
     },
     // Stable features.
diff --git a/codex-rs/features/src/tests.rs b/codex-rs/features/src/tests.rs
index 52437315dd..da6cb3c822 100644
--- a/codex-rs/features/src/tests.rs
+++ b/codex-rs/features/src/tests.rs
@@ -14,15 +14,6 @@ use std::collections::BTreeMap;
 use toml::Table;
 use toml::Value as TomlValue;
 
-#[test]
-fn transcript_v2_resolves_explicit_config_overrides() {
-    let mut features = Features::with_defaults();
-    for enabled in [false, true, false] {
-        features.apply_map(&BTreeMap::from([("transcript_v2".to_string(), enabled)]));
-        assert_eq!(features.enabled(Feature::TranscriptV2), enabled);
-    }
-}
-
 #[test]
 fn sleep_tool_config_rejects_unknown_mode() {
     assert!(toml::from_str::<FeaturesToml>("[sleep_tool]\nmode = 'off'").is_err());
diff --git a/codex-rs/thread-manager-sample/src/main.rs b/codex-rs/thread-manager-sample/src/main.rs
index 55d29288ca..f6ac386fb7 100644
--- a/codex-rs/thread-manager-sample/src/main.rs
+++ b/codex-rs/thread-manager-sample/src/main.rs
@@ -232,6 +232,7 @@ fn new_config(model: Option<String>, arg0_paths: Arg0DispatchPaths) -> anyhow::R
         tui_show_server_version_notice: true,
         tui_auto_recap: true,
         model_availability_nux: ModelAvailabilityNuxConfig::default(),
+        tui_fullscreen_transcript: false,
         tui_alternate_screen: AltScreenMode::Auto,
         tui_status_line: None,
         tui_status_line_use_colors: true,
diff --git a/codex-rs/tui/src/app/startup.rs b/codex-rs/tui/src/app/startup.rs
index efb4e8235a..867561454a 100644
--- a/codex-rs/tui/src/app/startup.rs
+++ b/codex-rs/tui/src/app/startup.rs
@@ -194,7 +194,7 @@ impl App {
         }
 
         // Adopt actual launch ownership before constructing session-local preferences.
-        tui.prepare_owned_screen(config.features.enabled(Feature::TranscriptV2))?;
+        tui.prepare_owned_screen(config.tui_fullscreen_transcript)?;
         let mut local_settings = crate::local_settings::LocalSettings::for_tui(&config, tui);
         let startup_started_at = Instant::now();
         let (app_event_tx, mut app_event_rx) = unbounded_channel();
diff --git a/codex-rs/tui/src/app/tests/history_hydration_tests.rs b/codex-rs/tui/src/app/tests/history_hydration_tests.rs
index 8e844a1258..9f28aecc6f 100644
--- a/codex-rs/tui/src/app/tests/history_hydration_tests.rs
+++ b/codex-rs/tui/src/app/tests/history_hydration_tests.rs
@@ -247,9 +247,7 @@ async fn history_hydration_archived_retry_uses_first_attempt_runtime_settings()
     ] {
         for mode in [TranscriptMode::Terminal, TranscriptMode::Owned] {
             let (mut app, codex_home, mut target) = history_fixture(&[500]).await?;
-            app.config
-                .features
-                .set_enabled(Feature::TranscriptV2, !mode.is_owned())?;
+            app.config.tui_fullscreen_transcript = !mode.is_owned();
             app.config.tui_alternate_screen = codex_config::types::AltScreenMode::Always;
             app.config.terminal_resize_reflow.max_rows = TerminalResizeReflowMaxRows::Limit(1);
             app.local_settings = crate::local_settings::LocalSettings::from(&app.config);
diff --git a/codex-rs/tui/src/app_server_session/history_tests.rs b/codex-rs/tui/src/app_server_session/history_tests.rs
index 4818985e64..0f12c95a81 100644
--- a/codex-rs/tui/src/app_server_session/history_tests.rs
+++ b/codex-rs/tui/src/app_server_session/history_tests.rs
@@ -5,7 +5,6 @@ use crate::legacy_core::config::ConfigBuilder;
 use crate::legacy_core::config::TerminalResizeReflowMaxRows;
 use crate::local_settings::LocalSettings;
 use codex_config::types::AltScreenMode;
-use codex_features::Feature;
 use pretty_assertions::assert_eq;
 use std::collections::HashSet;
 
@@ -42,10 +41,7 @@ async fn owned_initial_history_stops_after_viewport_or_scan_budget() {
         .build()
         .await
         .expect("config");
-    config
-        .features
-        .enable(Feature::TranscriptV2)
-        .expect("enable owned transcript");
+    config.tui_fullscreen_transcript = true;
     config.tui_alternate_screen = AltScreenMode::Always;
     config.terminal_resize_reflow.max_rows = TerminalResizeReflowMaxRows::Disabled;
     let local_settings = LocalSettings::from(&config);
@@ -78,10 +74,7 @@ async fn owned_initial_history_stops_after_viewport_or_scan_budget() {
         Some(100),
     );
 
-    config
-        .features
-        .disable(Feature::TranscriptV2)
-        .expect("disable owned transcript");
+    config.tui_fullscreen_transcript = false;
     // The mode selected at launch wins even if thread config changes or is unavailable.
     for config in [Some(&config), None] {
         let budget = HistoryLoadBudget::new(
diff --git a/codex-rs/tui/src/chatwidget/tests/dynamic_activity_tests.rs b/codex-rs/tui/src/chatwidget/tests/dynamic_activity_tests.rs
index d528070c66..cbb2e27d64 100644
--- a/codex-rs/tui/src/chatwidget/tests/dynamic_activity_tests.rs
+++ b/codex-rs/tui/src/chatwidget/tests/dynamic_activity_tests.rs
@@ -37,10 +37,7 @@ async fn terminal_dynamic_activity_retains_calls_across_both_fallbacks() {
         [(false, AltScreenMode::Always), (true, AltScreenMode::Never)]
     {
         let (mut chat, mut rx, _ops) = make_chatwidget_manual(/*model_override*/ None).await;
-        chat.config
-            .features
-            .set_enabled(Feature::TranscriptV2, owned_enabled)
-            .expect("configure transcript feature");
+        chat.config.tui_fullscreen_transcript = owned_enabled;
         chat.config.tui_alternate_screen = alternate_screen;
         chat.local_settings = LocalSettings::from(&chat.config);
         assert_eq!(
@@ -89,10 +86,7 @@ async fn owned_dynamic_activity_updates_the_retained_row_after_config_refresh()
     let (mut chat, mut rx, _ops) = make_chatwidget_manual(/*model_override*/ None).await;
     chat.local_settings.transcript_mode = TranscriptMode::Owned;
     // A thread/config refresh cannot change ownership after the terminal starts.
-    chat.config
-        .features
-        .disable(Feature::TranscriptV2)
-        .expect("disable transcript feature in refreshed config");
+    chat.config.tui_fullscreen_transcript = false;
     drain_insert_history(&mut rx);
     chat.on_dynamic_tool_item(dynamic_item("call-1", DynamicToolCallStatus::InProgress));
     let retained = std::iter::from_fn(|| rx.try_recv().ok())
diff --git a/codex-rs/tui/src/daemon_startup.rs b/codex-rs/tui/src/daemon_startup.rs
index c4164e808b..0e76635c3b 100644
--- a/codex-rs/tui/src/daemon_startup.rs
+++ b/codex-rs/tui/src/daemon_startup.rs
@@ -52,7 +52,10 @@ pub(super) fn config_exclusion(
     if !cli_kv_overrides
         .iter()
         .all(|(key, value)| match key.as_str() {
-            "suppress_unstable_features_warning" => value.is_bool(),
+            "suppress_unstable_features_warning" | "tui.fullscreen_transcript" => value.is_bool(),
+            "tui" => value.as_table().is_some_and(|tui| {
+                tui.len() == 1 && tui.get("fullscreen_transcript").is_some_and(toml::Value::is_bool)
+            }),
             "features" => value.as_table().is_some_and(|features| {
                 !features.is_empty()
                     && features
diff --git a/codex-rs/tui/src/daemon_startup_tests.rs b/codex-rs/tui/src/daemon_startup_tests.rs
index 28a0bf9fb7..15c62b7d08 100644
--- a/codex-rs/tui/src/daemon_startup_tests.rs
+++ b/codex-rs/tui/src/daemon_startup_tests.rs
@@ -27,6 +27,12 @@ fn audited_overrides_allow_daemon_without_allowing_arbitrary_config() {
         ("features={worktrees=true,shell_tool=false}", false),
         ("features.shell_tool=false", false),
         ("features.worktrees.enabled=true", false),
+        ("tui.fullscreen_transcript=true", true),
+        ("tui.fullscreen_transcript=false", true),
+        ("tui.fullscreen_transcript=\"true\"", false),
+        ("tui={fullscreen_transcript=true}", true),
+        ("tui={fullscreen_transcript='true'}", false),
+        ("tui={fullscreen_transcript=true,animations=false}", false),
         ("features={}", false),
         ("model='test'", false),
     ] {
diff --git a/codex-rs/tui/src/lib.rs b/codex-rs/tui/src/lib.rs
index e602ca2018..4e2490e5fb 100644
--- a/codex-rs/tui/src/lib.rs
+++ b/codex-rs/tui/src/lib.rs
@@ -1843,7 +1843,7 @@ async fn run_ratatui_app(
     // Cloud configuration and session selection can change screen policy after first paint.
     let use_alt_screen = determine_alt_screen_mode(cli.no_alt_screen, config.tui_alternate_screen);
     let mode = crate::transcript_mode::TranscriptMode::resolve(
-        config.features.enabled(Feature::TranscriptV2),
+        config.tui_fullscreen_transcript,
         use_alt_screen,
     );
     if use_alt_screen != tui.is_alt_screen_enabled() || mode.is_owned() != tui.is_owned_screen() {
diff --git a/codex-rs/tui/src/local_settings.rs b/codex-rs/tui/src/local_settings.rs
index 7723e8d521..f60e5f5d8f 100644
--- a/codex-rs/tui/src/local_settings.rs
+++ b/codex-rs/tui/src/local_settings.rs
@@ -13,7 +13,6 @@ use crate::transcript_mode::TranscriptMode;
 use codex_config::types::History;
 use codex_config::types::Notice;
 use codex_config::types::Tui;
-use codex_features::Feature;
 use codex_utils_absolute_path::AbsolutePathBuf;
 
 #[derive(Clone, Debug, PartialEq)]
@@ -56,7 +55,7 @@ impl LocalSettings {
         };
         Self {
             transcript_mode: TranscriptMode::resolve(
-                config.features.enabled(Feature::TranscriptV2),
+                config.tui_fullscreen_transcript,
                 config.tui_alternate_screen != codex_config::types::AltScreenMode::Never,
             ),
             tui: Tui {
@@ -71,6 +70,7 @@ impl LocalSettings {
                 vim_mode_default: config.tui_vim_mode_default,
                 question_esc_back: config.tui_question_esc_back,
                 raw_output_mode: config.tui_raw_output_mode,
+                fullscreen_transcript: config.tui_fullscreen_transcript,
                 alternate_screen: config.tui_alternate_screen,
                 status_line: config.tui_status_line.clone(),
                 status_line_use_colors: config.tui_status_line_use_colors,
diff --git a/codex-rs/tui/src/local_settings_tests.rs b/codex-rs/tui/src/local_settings_tests.rs
index 12aae2c516..cef866fbd4 100644
--- a/codex-rs/tui/src/local_settings_tests.rs
+++ b/codex-rs/tui/src/local_settings_tests.rs
@@ -16,7 +16,7 @@ async fn launch_screen_mode_survives_configuration_reload() -> anyhow::Result<()
         .loader_overrides(LoaderOverrides::without_managed_config_for_tests())
         .build()
         .await?;
-    config.features.enable(Feature::TranscriptV2)?;
+    config.tui_fullscreen_transcript = true;
     config.tui_alternate_screen = AltScreenMode::Auto;
 
     for (alternate_screen, owned, expected_mode, expected_alt) in [
@@ -34,7 +34,7 @@ async fn launch_screen_mode_survives_configuration_reload() -> anyhow::Result<()
         );
 
         let mut reloaded_config = config.clone();
-        reloaded_config.features.disable(Feature::TranscriptV2)?;
+        reloaded_config.tui_fullscreen_transcript = false;
         reloaded_config.tui_alternate_screen = AltScreenMode::Never;
         reloaded_config.tui_theme = Some("nord".into());
         let mut expected = LocalSettings::from(&reloaded_config);
@@ -98,6 +98,7 @@ whimsy = false # Retired: must not override effects or prevent strict loading.
 show_tooltips = false
 show_server_version_notice = false
 auto_recap = false
+fullscreen_transcript = true
 vim_mode_default = true
 terminal_resize_reflow_max_rows = 0
 session_picker_view = "comfortable"
@@ -119,7 +120,14 @@ fast_default_opt_out = true
                 ignore_project_config: true,
                 ..LoaderOverrides::without_managed_config_for_tests()
             })
-            .cli_overrides(vec![("tui.disable_paste_burst".into(), true.into())])
+            .cli_overrides(vec![
+                ("tui.disable_paste_burst".into(), true.into()),
+                // The deprecated flag must not override or migrate into the TUI preference.
+                (
+                    "features.transcript_v2".into(),
+                    config_text.is_empty().into(),
+                ),
+            ])
             .build()
             .await?;
         assert_eq!(config.startup_warnings, Vec::<String>::new());
@@ -133,11 +141,24 @@ fast_default_opt_out = true
             expected.show_tooltips = false;
             expected.show_server_version_notice = false;
             expected.auto_recap = false;
+            expected.fullscreen_transcript = true;
             expected.vim_mode_default = true;
             expected.terminal_resize_reflow_max_rows = Some(0);
             expected.session_picker_view = Some(SessionPickerViewMode::Comfortable);
         }
+        assert_eq!(
+            local.transcript_mode.is_owned(),
+            expected.fullscreen_transcript
+        );
         assert_eq!(local.tui, expected);
+        assert_eq!(
+            config
+                .features
+                .legacy_feature_usages()
+                .map(|usage| usage.alias.as_str())
+                .collect::<Vec<_>>(),
+            vec!["features.transcript_v2"],
+        );
         assert_eq!(
             local.terminal_resize_reflow(),
             config.terminal_resize_reflow
diff --git a/codex-rs/tui/src/startup_presentation.rs b/codex-rs/tui/src/startup_presentation.rs
index 5ce74e4634..f332ef09c1 100644
--- a/codex-rs/tui/src/startup_presentation.rs
+++ b/codex-rs/tui/src/startup_presentation.rs
@@ -12,16 +12,11 @@ use codex_config::CloudConfigBundleLoader;
 use codex_config::ConfigLoadOptions;
 use codex_config::LoaderOverrides;
 use codex_config::TomlValue;
-use codex_features::Feature;
-use codex_features::FeatureConfigSource;
-use codex_features::FeatureOverrides;
-use codex_features::Features;
 use codex_utils_absolute_path::AbsolutePathBuf;
 
 use crate::Cli;
 use crate::keymap::RuntimeKeymap;
 use crate::legacy_core::config::ConfigTomlLoadResult;
-use crate::legacy_core::config::ManagedFeatures;
 use crate::legacy_core::config::load_config_toml_with_layer_stack;
 use crate::startup_draft::StartupScreen;
 
@@ -56,25 +51,6 @@ pub(super) async fn load(
     )
     .await?;
     let config_toml = &bootstrap_config.config_toml;
-    let configured_features = Features::from_sources(
-        FeatureConfigSource {
-            features: config_toml.features.as_ref(),
-            experimental_use_unified_exec_tool: config_toml.experimental_use_unified_exec_tool,
-        },
-        FeatureConfigSource::default(),
-        FeatureOverrides::default(),
-    );
-    // Full configuration construction will publish its normal managed-feature warnings once.
-    let mut startup_warnings = Vec::new();
-    let features = ManagedFeatures::from_configured_with_warnings(
-        configured_features,
-        bootstrap_config
-            .config_layer_stack
-            .requirements()
-            .feature_requirements
-            .clone(),
-        &mut startup_warnings,
-    )?;
     let alternate_screen = config_toml
         .tui
         .as_ref()
@@ -82,7 +58,10 @@ pub(super) async fn load(
         .unwrap_or_default();
     let use_alt_screen = crate::determine_alt_screen_mode(cli.no_alt_screen, alternate_screen);
     let transcript_mode = crate::transcript_mode::TranscriptMode::resolve(
-        features.enabled(Feature::TranscriptV2),
+        config_toml
+            .tui
+            .as_ref()
+            .is_some_and(|tui| tui.fullscreen_transcript),
         use_alt_screen,
     );
     let status_line_enabled = config_toml
diff --git a/codex-rs/tui/src/startup_presentation_tests.rs b/codex-rs/tui/src/startup_presentation_tests.rs
index 5cf50dcaba..b1cc9157f2 100644
--- a/codex-rs/tui/src/startup_presentation_tests.rs
+++ b/codex-rs/tui/src/startup_presentation_tests.rs
@@ -50,23 +50,24 @@ async fn selected_profile_controls_submit_before_the_first_frame() -> anyhow::Re
 async fn first_frame_respects_screen_and_status_line_overrides() -> anyhow::Result<()> {
     let home = tempfile::tempdir()?;
     for (config, args, expected) in [
+        ("", vec!["codex"], (true, false, true)),
         (
-            "[features]\ntranscript_v2 = true\n",
+            "[tui]\nfullscreen_transcript = true\n",
             vec!["codex"],
             (true, true, true),
         ),
         (
-            "[features]\ntranscript_v2 = true\n",
+            "[tui]\nfullscreen_transcript = true\n",
             vec!["codex", "--no-alt-screen"],
             (false, false, true),
         ),
         (
-            "[features]\ntranscript_v2 = false\n",
+            "[tui]\nfullscreen_transcript = false\n",
             vec!["codex"],
             (true, false, true),
         ),
         (
-            "[tui]\nalternate_screen = \"never\"\nstatus_line = []\n",
+            "[tui]\nfullscreen_transcript = true\nalternate_screen = \"never\"\nstatus_line = []\n",
             vec!["codex"],
             (false, false, false),
         ),
diff --git a/codex-rs/tui/tests/suite/focus_palette.rs b/codex-rs/tui/tests/suite/focus_palette.rs
index 816b8191a6..d13af5ad7b 100644
--- a/codex-rs/tui/tests/suite/focus_palette.rs
+++ b/codex-rs/tui/tests/suite/focus_palette.rs
@@ -161,12 +161,7 @@ fn owned_screen_entry_paints_before_sync_ends_and_exit_clears_inline_draft() ->
     let mut terminal = PtyCodex::start(
         &repo_root,
         codex_home,
-        &[
-            "-c",
-            "tui.alternate_screen=\"always\"",
-            "-c",
-            "features.transcript_v2=true",
-        ],
+        &["-c", "tui.fullscreen_transcript=true"],
     )?;
     terminal.wait_for_startup()?;
     let deadline = Instant::now() + STARTUP_TIMEOUT;
@@ -180,6 +175,10 @@ fn owned_screen_entry_paints_before_sync_ends_and_exit_clears_inline_draft() ->
         "owned screen did not open"
     );
     terminal.wait_for_screen("GPT-5.6-Terra")?;
+    ensure!(
+        terminal.parser.screen().alternate_screen(),
+        "fullscreen did not survive application startup"
+    );
     let enter_alt = b"\x1b[?1049h";
     let begin_sync = b"\x1b[?2026h";
     let end_sync = b"\x1b[?2026l";
@@ -252,6 +251,24 @@ fn owned_screen_entry_paints_before_sync_ends_and_exit_clears_inline_draft() ->
     Ok(())
 }
 
+#[test]
+fn fullscreen_transcript_defaults_to_terminal_scrollback() -> Result<()> {
+    let repo_root = codex_utils_cargo_bin::repo_root()?;
+    let codex_home = tempfile::tempdir()?;
+    write_test_config(codex_home.path(), &repo_root)?;
+    let mut terminal = PtyCodex::start(&repo_root, codex_home, &[])?;
+    terminal.wait_for_startup()?;
+    terminal.wait_for_screen("GPT-5.6-Terra")?;
+    ensure!(
+        !terminal
+            .output
+            .windows(b"\x1b[?1049h".len())
+            .any(|bytes| bytes == b"\x1b[?1049h"),
+        "default launch entered the alternate screen"
+    );
+    Ok(())
+}
+
 pub(super) struct PtyCodex {
     master: File,
     child: Child,