Make model switcher two-stage (#4178)

https://github.com/user-attachments/assets/16d5c67c-e580-4a29-983c-a315f95424ee

codex-rs/common/src/model_presets.rs

@@ -20,49 +20,49 @@ const PRESETS: &[ModelPreset] = &[
     ModelPreset {
         id: "gpt-5-codex-low",
         label: "gpt-5-codex low",
-        description: "",
+        description: "Fastest responses with limited reasoning",
         model: "gpt-5-codex",
         effort: Some(ReasoningEffort::Low),
     },
     ModelPreset {
         id: "gpt-5-codex-medium",
         label: "gpt-5-codex medium",
-        description: "",
+        description: "Dynamically adjusts reasoning based on the task",
         model: "gpt-5-codex",
         effort: Some(ReasoningEffort::Medium),
     },
     ModelPreset {
         id: "gpt-5-codex-high",
         label: "gpt-5-codex high",
-        description: "",
+        description: "Maximizes reasoning depth for complex or ambiguous problems",
         model: "gpt-5-codex",
         effort: Some(ReasoningEffort::High),
     },
     ModelPreset {
         id: "gpt-5-minimal",
         label: "gpt-5 minimal",
-        description: "— fastest responses with limited reasoning; ideal for coding, instructions, or lightweight tasks",
+        description: "Fastest responses with little reasoning",
         model: "gpt-5",
         effort: Some(ReasoningEffort::Minimal),
     },
     ModelPreset {
         id: "gpt-5-low",
         label: "gpt-5 low",
-        description: "— balances speed with some reasoning; useful for straightforward queries and short explanations",
+        description: "Balances speed with some reasoning; useful for straightforward queries and short explanations",
         model: "gpt-5",
         effort: Some(ReasoningEffort::Low),
     },
     ModelPreset {
         id: "gpt-5-medium",
         label: "gpt-5 medium",
-        description: "— default setting; provides a solid balance of reasoning depth and latency for general-purpose tasks",
+        description: "Provides a solid balance of reasoning depth and latency for general-purpose tasks",
         model: "gpt-5",
         effort: Some(ReasoningEffort::Medium),
     },
     ModelPreset {
         id: "gpt-5-high",
         label: "gpt-5 high",
-        description: "— maximizes reasoning depth for complex or ambiguous problems",
+        description: "Maximizes reasoning depth for complex or ambiguous problems",
         model: "gpt-5",
         effort: Some(ReasoningEffort::High),
     },

codex-rs/tui/src/app.rs

@@ -320,24 +320,28 @@ impl App {
                     self.config.model_family = family;
                 }
             }
+            AppEvent::OpenReasoningPopup { model, presets } => {
+                self.chat_widget.open_reasoning_popup(model, presets);
+            }
             AppEvent::PersistModelSelection { model, effort } => {
                 let profile = self.active_profile.as_deref();
                 match persist_model_selection(&self.config.codex_home, profile, &model, effort)
                     .await
                 {
                     Ok(()) => {
+                        let effort_label = effort
+                            .map(|eff| format!(" with {eff} reasoning"))
+                            .unwrap_or_else(|| " with default reasoning".to_string());
                         if let Some(profile) = profile {
                             self.chat_widget.add_info_message(
-                                format!("Model changed to {model}{reasoning_effort} for {profile} profile", reasoning_effort = effort.map(|e| format!(" {e}")).unwrap_or_default()),
+                                format!(
+                                    "Model changed to {model}{effort_label} for {profile} profile"
+                                ),
                                 None,
                             );
                         } else {
                             self.chat_widget.add_info_message(
-                                format!(
+                                format!("Model changed to {model}{effort_label}"),
-                                    "Model changed to {model}{reasoning_effort}",
-                                    reasoning_effort =
-                                        effort.map(|e| format!(" {e}")).unwrap_or_default()
-                                ),
                                 None,
                             );
                         }

codex-rs/tui/src/app_event.rs

@@ -1,5 +1,6 @@
 use std::path::PathBuf;
 
+use codex_common::model_presets::ModelPreset;
 use codex_core::protocol::ConversationPathResponseEvent;
 use codex_core::protocol::Event;
 use codex_file_search::FileMatch;
@@ -60,6 +61,12 @@ pub(crate) enum AppEvent {
         effort: Option<ReasoningEffort>,
     },
 
+    /// Open the reasoning selection popup after picking a model.
+    OpenReasoningPopup {
+        model: String,
+        presets: Vec<ModelPreset>,
+    },
+
     /// Update the current approval policy in the running app and widget.
     UpdateAskForApprovalPolicy(AskForApproval),
 

codex-rs/tui/src/chatwidget.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::collections::VecDeque;
 use std::path::PathBuf;
@@ -111,6 +112,7 @@ use codex_git_tooling::GhostCommit;
 use codex_git_tooling::GitToolingError;
 use codex_git_tooling::create_ghost_commit;
 use codex_git_tooling::restore_ghost_commit;
+use strum::IntoEnumIterator;
 
 const MAX_TRACKED_GHOST_COMMITS: usize = 20;
 
@@ -283,6 +285,16 @@ fn create_initial_user_message(text: String, image_paths: Vec<PathBuf>) -> Optio
 }
 
 impl ChatWidget {
+    fn model_description_for(slug: &str) -> Option<&'static str> {
+        if slug.starts_with("gpt-5-codex") {
+            Some("Optimized for coding tasks with many tools.")
+        } else if slug.starts_with("gpt-5") {
+            Some("Broad world knowledge with strong general reasoning.")
+        } else {
+            None
+        }
+    }
+
     fn flush_answer_stream_with_separator(&mut self) {
         if let Some(mut controller) = self.stream_controller.take()
             && let Some(cell) = controller.finalize()
@@ -1579,47 +1591,38 @@ impl ChatWidget {
         ));
     }
 
-    /// Open a popup to choose the model preset (model + reasoning effort).
+    /// Open a popup to choose the model (stage 1). After selecting a model,
+    /// a second popup is shown to choose the reasoning effort.
     pub(crate) fn open_model_popup(&mut self) {
         let current_model = self.config.model.clone();
-        let current_effort = self.config.model_reasoning_effort;
         let auth_mode = self.auth_manager.auth().map(|auth| auth.mode);
         let presets: Vec<ModelPreset> = builtin_model_presets(auth_mode);
 
+        let mut grouped: BTreeMap<&str, Vec<ModelPreset>> = BTreeMap::new();
+        for preset in presets.into_iter() {
+            grouped.entry(preset.model).or_default().push(preset);
+        }
+
         let mut items: Vec<SelectionItem> = Vec::new();
-        for preset in presets.iter() {
+        for (model_slug, entries) in grouped.into_iter() {
-            let name = preset.label.to_string();
+            let name = model_slug.to_string();
-            let description = Some(preset.description.to_string());
+            let description = Self::model_description_for(model_slug)
-            let is_current = preset.model == current_model && preset.effort == current_effort;
+                .map(std::string::ToString::to_string)
-            let model_slug = preset.model.to_string();
+                .or_else(|| {
-            let effort = preset.effort;
+                    entries
-            let current_model = current_model.clone();
+                        .iter()
+                        .find(|preset| !preset.description.is_empty())
+                        .map(|preset| preset.description.to_string())
+                })
+                .or_else(|| entries.first().map(|preset| preset.description.to_string()));
+            let is_current = model_slug == current_model;
+            let model_slug_string = model_slug.to_string();
+            let presets_for_model = entries.clone();
             let actions: Vec<SelectionAction> = vec![Box::new(move |tx| {
-                tx.send(AppEvent::CodexOp(Op::OverrideTurnContext {
+                tx.send(AppEvent::OpenReasoningPopup {
-                    cwd: None,
+                    model: model_slug_string.clone(),
-                    approval_policy: None,
+                    presets: presets_for_model.clone(),
-                    sandbox_policy: None,
-                    model: Some(model_slug.clone()),
-                    effort: Some(effort),
-                    summary: None,
-                }));
-                tx.send(AppEvent::UpdateModel(model_slug.clone()));
-                tx.send(AppEvent::UpdateReasoningEffort(effort));
-                tx.send(AppEvent::PersistModelSelection {
-                    model: model_slug.clone(),
-                    effort,
                 });
-                tracing::info!(
-                    "New model: {}, New effort: {}, Current model: {}, Current effort: {}",
-                    model_slug.clone(),
-                    effort
-                        .map(|effort| effort.to_string())
-                        .unwrap_or_else(|| "none".to_string()),
-                    current_model,
-                    current_effort
-                        .map(|effort| effort.to_string())
-                        .unwrap_or_else(|| "none".to_string())
-                );
             })];
             items.push(SelectionItem {
                 name,
@@ -1632,10 +1635,127 @@ impl ChatWidget {
         }
 
         self.bottom_pane.show_selection_view(SelectionViewParams {
-            title: Some("Select model and reasoning level".to_string()),
+            title: Some("Select Model".to_string()),
-            subtitle: Some(
+            subtitle: Some("Switch the model for this and future Codex CLI sessions".to_string()),
-                "Switch between OpenAI models for this and future Codex CLI session".to_string(),
+            footer_hint: Some(standard_popup_hint_line()),
-            ),
+            items,
+            ..Default::default()
+        });
+    }
+
+    /// Open a popup to choose the reasoning effort (stage 2) for the given model.
+    pub(crate) fn open_reasoning_popup(&mut self, model_slug: String, presets: Vec<ModelPreset>) {
+        let default_effort = ReasoningEffortConfig::default();
+
+        let has_none_choice = presets.iter().any(|preset| preset.effort.is_none());
+        struct EffortChoice {
+            stored: Option<ReasoningEffortConfig>,
+            display: ReasoningEffortConfig,
+        }
+        let mut choices: Vec<EffortChoice> = Vec::new();
+        for effort in ReasoningEffortConfig::iter() {
+            if presets.iter().any(|preset| preset.effort == Some(effort)) {
+                choices.push(EffortChoice {
+                    stored: Some(effort),
+                    display: effort,
+                });
+            }
+            if has_none_choice && default_effort == effort {
+                choices.push(EffortChoice {
+                    stored: None,
+                    display: effort,
+                });
+            }
+        }
+        if choices.is_empty() {
+            choices.push(EffortChoice {
+                stored: Some(default_effort),
+                display: default_effort,
+            });
+        }
+
+        let default_choice: Option<ReasoningEffortConfig> = if has_none_choice {
+            None
+        } else if choices
+            .iter()
+            .any(|choice| choice.stored == Some(default_effort))
+        {
+            Some(default_effort)
+        } else {
+            choices
+                .iter()
+                .find_map(|choice| choice.stored)
+                .or(Some(default_effort))
+        };
+
+        let is_current_model = self.config.model == model_slug;
+        let highlight_choice = if is_current_model {
+            self.config.model_reasoning_effort
+        } else {
+            default_choice
+        };
+
+        let mut items: Vec<SelectionItem> = Vec::new();
+        for choice in choices.iter() {
+            let effort = choice.display;
+            let mut effort_label = effort.to_string();
+            if let Some(first) = effort_label.get_mut(0..1) {
+                first.make_ascii_uppercase();
+            }
+            if choice.stored == default_choice {
+                effort_label.push_str(" (default)");
+            }
+
+            let description = presets
+                .iter()
+                .find(|preset| preset.effort == choice.stored && !preset.description.is_empty())
+                .map(|preset| preset.description.to_string())
+                .or_else(|| {
+                    presets
+                        .iter()
+                        .find(|preset| preset.effort == choice.stored)
+                        .map(|preset| preset.description.to_string())
+                });
+
+            let model_for_action = model_slug.clone();
+            let effort_for_action = choice.stored;
+            let actions: Vec<SelectionAction> = vec![Box::new(move |tx| {
+                tx.send(AppEvent::CodexOp(Op::OverrideTurnContext {
+                    cwd: None,
+                    approval_policy: None,
+                    sandbox_policy: None,
+                    model: Some(model_for_action.clone()),
+                    effort: Some(effort_for_action),
+                    summary: None,
+                }));
+                tx.send(AppEvent::UpdateModel(model_for_action.clone()));
+                tx.send(AppEvent::UpdateReasoningEffort(effort_for_action));
+                tx.send(AppEvent::PersistModelSelection {
+                    model: model_for_action.clone(),
+                    effort: effort_for_action,
+                });
+                tracing::info!(
+                    "Selected model: {}, Selected effort: {}",
+                    model_for_action,
+                    effort_for_action
+                        .map(|e| e.to_string())
+                        .unwrap_or_else(|| "default".to_string())
+                );
+            })];
+
+            items.push(SelectionItem {
+                name: effort_label,
+                description,
+                is_current: is_current_model && choice.stored == highlight_choice,
+                actions,
+                dismiss_on_select: true,
+                search_value: None,
+            });
+        }
+
+        self.bottom_pane.show_selection_view(SelectionViewParams {
+            title: Some("Select Reasoning Level".to_string()),
+            subtitle: Some(format!("Reasoning for model {model_slug}")),
             footer_hint: Some(standard_popup_hint_line()),
             items,
             ..Default::default()

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__model_reasoning_selection_popup.snap

@@ -0,0 +1,13 @@
+---
+source: tui/src/chatwidget/tests.rs
+expression: popup
+---
+  Select Reasoning Level
+  Reasoning for model gpt-5-codex
+
+  1. Low               Fastest responses with limited reasoning
+  2. Medium (default)  Dynamically adjusts reasoning based on the task
+› 3. High (current)    Maximizes reasoning depth for complex or ambiguous
+                       problems
+
+  Press enter to confirm or esc to go back

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__model_selection_popup.snap

@@ -0,0 +1,12 @@
+---
+source: tui/src/chatwidget/tests.rs
+expression: popup
+---
+  Select Model
+  Switch the model for this and future Codex CLI sessions
+
+  1. gpt-5                  Broad world knowledge with strong general
+                            reasoning.
+› 2. gpt-5-codex (current)  Optimized for coding tasks with many tools.
+
+  Press enter to confirm or esc to go back

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

@@ -936,6 +936,65 @@ fn render_bottom_first_row(chat: &ChatWidget, width: u16) -> String {
     String::new()
 }
 
+fn render_bottom_popup(chat: &ChatWidget, width: u16) -> String {
+    let height = chat.desired_height(width);
+    let area = Rect::new(0, 0, width, height);
+    let mut buf = Buffer::empty(area);
+    (chat).render_ref(area, &mut buf);
+
+    let mut lines: Vec<String> = (0..area.height)
+        .map(|row| {
+            let mut line = String::new();
+            for col in 0..area.width {
+                let symbol = buf[(area.x + col, area.y + row)].symbol();
+                if symbol.is_empty() {
+                    line.push(' ');
+                } else {
+                    line.push_str(symbol);
+                }
+            }
+            line.trim_end().to_string()
+        })
+        .collect();
+
+    while lines.first().is_some_and(|line| line.trim().is_empty()) {
+        lines.remove(0);
+    }
+    while lines.last().is_some_and(|line| line.trim().is_empty()) {
+        lines.pop();
+    }
+
+    lines.join("\n")
+}
+
+#[test]
+fn model_selection_popup_snapshot() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual();
+
+    chat.config.model = "gpt-5-codex".to_string();
+    chat.open_model_popup();
+
+    let popup = render_bottom_popup(&chat, 80);
+    assert_snapshot!("model_selection_popup", popup);
+}
+
+#[test]
+fn model_reasoning_selection_popup_snapshot() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual();
+
+    chat.config.model = "gpt-5-codex".to_string();
+    chat.config.model_reasoning_effort = Some(ReasoningEffortConfig::High);
+
+    let presets = builtin_model_presets(None)
+        .into_iter()
+        .filter(|preset| preset.model == "gpt-5-codex")
+        .collect::<Vec<_>>();
+    chat.open_reasoning_popup("gpt-5-codex".to_string(), presets);
+
+    let popup = render_bottom_popup(&chat, 80);
+    assert_snapshot!("model_reasoning_selection_popup", popup);
+}
+
 #[test]
 fn exec_history_extends_previous_when_consecutive() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual();