[app-server] model/list API (#5382)

Adds a `model/list` paginated API that returns the list of models
supported by Codex.

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

@@ -106,6 +106,13 @@ client_request_definitions! {
         params: ListConversationsParams,
         response: ListConversationsResponse,
     },
+    #[serde(rename = "model/list")]
+    #[ts(rename = "model/list")]
+    /// List available Codex models along with display metadata.
+    ListModels {
+        params: ListModelsParams,
+        response: ListModelsResponse,
+    },
     /// Resume a recorded Codex conversation from a rollout file.
     ResumeConversation {
         params: ResumeConversationParams,
@@ -304,6 +311,47 @@ pub struct ListConversationsResponse {
     pub next_cursor: Option<String>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct ListModelsParams {
+    /// Optional page size; defaults to a reasonable server-side value.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub page_size: Option<usize>,
+    /// Opaque pagination cursor returned by a previous call.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub cursor: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct Model {
+    pub id: String,
+    pub model: String,
+    pub display_name: String,
+    pub description: String,
+    pub supported_reasoning_efforts: Vec<ReasoningEffortOption>,
+    pub default_reasoning_effort: ReasoningEffort,
+    // Only one model should be marked as default.
+    pub is_default: bool,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct ReasoningEffortOption {
+    pub reasoning_effort: ReasoningEffort,
+    pub description: String,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct ListModelsResponse {
+    pub items: Vec<Model>,
+    /// Opaque cursor to pass to the next call to continue after the last item.
+    /// if None, there are no more items to return.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub next_cursor: Option<String>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 pub struct ResumeConversationParams {
@@ -994,4 +1042,21 @@ mod tests {
         );
         Ok(())
     }
+
+    #[test]
+    fn serialize_list_models() -> Result<()> {
+        let request = ClientRequest::ListModels {
+            request_id: RequestId::Integer(2),
+            params: ListModelsParams::default(),
+        };
+        assert_eq!(
+            json!({
+                "method": "model/list",
+                "id": 2,
+                "params": {}
+            }),
+            serde_json::to_value(&request)?,
+        );
+        Ok(())
+    }
 }

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

@@ -1,6 +1,7 @@
 use crate::error_code::INTERNAL_ERROR_CODE;
 use crate::error_code::INVALID_REQUEST_ERROR_CODE;
 use crate::fuzzy_file_search::run_fuzzy_file_search;
+use crate::models::supported_models;
 use crate::outgoing_message::OutgoingMessageSender;
 use crate::outgoing_message::OutgoingNotification;
 use codex_app_server_protocol::AddConversationListenerParams;
@@ -29,6 +30,8 @@ use codex_app_server_protocol::InterruptConversationResponse;
 use codex_app_server_protocol::JSONRPCErrorError;
 use codex_app_server_protocol::ListConversationsParams;
 use codex_app_server_protocol::ListConversationsResponse;
+use codex_app_server_protocol::ListModelsParams;
+use codex_app_server_protocol::ListModelsResponse;
 use codex_app_server_protocol::LoginApiKeyParams;
 use codex_app_server_protocol::LoginApiKeyResponse;
 use codex_app_server_protocol::LoginChatGptCompleteNotification;
@@ -111,7 +114,6 @@ use uuid::Uuid;
 
 // Duration before a ChatGPT login attempt is abandoned.
 const LOGIN_CHATGPT_TIMEOUT: Duration = Duration::from_secs(10 * 60);
-
 struct ActiveLogin {
     shutdown_handle: ShutdownHandle,
     login_id: Uuid,
@@ -172,6 +174,9 @@ impl CodexMessageProcessor {
             ClientRequest::ListConversations { request_id, params } => {
                 self.handle_list_conversations(request_id, params).await;
             }
+            ClientRequest::ListModels { request_id, params } => {
+                self.list_models(request_id, params).await;
+            }
             ClientRequest::ResumeConversation { request_id, params } => {
                 self.handle_resume_conversation(request_id, params).await;
             }
@@ -831,6 +836,58 @@ impl CodexMessageProcessor {
         self.outgoing.send_response(request_id, response).await;
     }
 
+    async fn list_models(&self, request_id: RequestId, params: ListModelsParams) {
+        let ListModelsParams { page_size, cursor } = params;
+        let models = supported_models();
+        let total = models.len();
+
+        if total == 0 {
+            let response = ListModelsResponse {
+                items: Vec::new(),
+                next_cursor: None,
+            };
+            self.outgoing.send_response(request_id, response).await;
+            return;
+        }
+
+        let effective_page_size = page_size.unwrap_or(total).max(1).min(total);
+        let start = match cursor {
+            Some(cursor) => match cursor.parse::<usize>() {
+                Ok(idx) => idx,
+                Err(_) => {
+                    let error = JSONRPCErrorError {
+                        code: INVALID_REQUEST_ERROR_CODE,
+                        message: format!("invalid cursor: {cursor}"),
+                        data: None,
+                    };
+                    self.outgoing.send_error(request_id, error).await;
+                    return;
+                }
+            },
+            None => 0,
+        };
+
+        if start > total {
+            let error = JSONRPCErrorError {
+                code: INVALID_REQUEST_ERROR_CODE,
+                message: format!("cursor {start} exceeds total models {total}"),
+                data: None,
+            };
+            self.outgoing.send_error(request_id, error).await;
+            return;
+        }
+
+        let end = start.saturating_add(effective_page_size).min(total);
+        let items = models[start..end].to_vec();
+        let next_cursor = if end < total {
+            Some(end.to_string())
+        } else {
+            None
+        };
+        let response = ListModelsResponse { items, next_cursor };
+        self.outgoing.send_response(request_id, response).await;
+    }
+
     async fn handle_resume_conversation(
         &self,
         request_id: RequestId,

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

@@ -27,6 +27,7 @@ mod codex_message_processor;
 mod error_code;
 mod fuzzy_file_search;
 mod message_processor;
+mod models;
 mod outgoing_message;
 
 /// Size of the bounded channels used to communicate between tasks. The value

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

@@ -0,0 +1,38 @@
+use codex_app_server_protocol::Model;
+use codex_app_server_protocol::ReasoningEffortOption;
+use codex_common::model_presets::ModelPreset;
+use codex_common::model_presets::ReasoningEffortPreset;
+use codex_common::model_presets::builtin_model_presets;
+
+pub fn supported_models() -> Vec<Model> {
+    builtin_model_presets(None)
+        .into_iter()
+        .map(model_from_preset)
+        .collect()
+}
+
+fn model_from_preset(preset: ModelPreset) -> Model {
+    Model {
+        id: preset.id.to_string(),
+        model: preset.model.to_string(),
+        display_name: preset.display_name.to_string(),
+        description: preset.description.to_string(),
+        supported_reasoning_efforts: reasoning_efforts_from_preset(
+            preset.supported_reasoning_efforts,
+        ),
+        default_reasoning_effort: preset.default_reasoning_effort,
+        is_default: preset.is_default,
+    }
+}
+
+fn reasoning_efforts_from_preset(
+    efforts: &'static [ReasoningEffortPreset],
+) -> Vec<ReasoningEffortOption> {
+    efforts
+        .iter()
+        .map(|preset| ReasoningEffortOption {
+            reasoning_effort: preset.effort,
+            description: preset.description.to_string(),
+        })
+        .collect()
+}

codex-rs/app-server/tests/common/mcp_process.rs

@@ -21,6 +21,7 @@ use codex_app_server_protocol::GetAuthStatusParams;
 use codex_app_server_protocol::InitializeParams;
 use codex_app_server_protocol::InterruptConversationParams;
 use codex_app_server_protocol::ListConversationsParams;
+use codex_app_server_protocol::ListModelsParams;
 use codex_app_server_protocol::LoginApiKeyParams;
 use codex_app_server_protocol::NewConversationParams;
 use codex_app_server_protocol::RemoveConversationListenerParams;
@@ -264,6 +265,15 @@ impl McpProcess {
         self.send_request("listConversations", params).await
     }
 
+    /// Send a `model/list` JSON-RPC request.
+    pub async fn send_list_models_request(
+        &mut self,
+        params: ListModelsParams,
+    ) -> anyhow::Result<i64> {
+        let params = Some(serde_json::to_value(params)?);
+        self.send_request("model/list", params).await
+    }
+
     /// Send a `resumeConversation` JSON-RPC request.
     pub async fn send_resume_conversation_request(
         &mut self,

codex-rs/app-server/tests/suite/mod.rs

@@ -7,6 +7,7 @@ mod fuzzy_file_search;
 mod interrupt;
 mod list_resume;
 mod login;
+mod model_list;
 mod rate_limits;
 mod send_message;
 mod set_default_model;

codex-rs/app-server/tests/suite/model_list.rs

@@ -0,0 +1,183 @@
+use std::time::Duration;
+
+use anyhow::Result;
+use anyhow::anyhow;
+use app_test_support::McpProcess;
+use app_test_support::to_response;
+use codex_app_server_protocol::JSONRPCError;
+use codex_app_server_protocol::JSONRPCResponse;
+use codex_app_server_protocol::ListModelsParams;
+use codex_app_server_protocol::ListModelsResponse;
+use codex_app_server_protocol::Model;
+use codex_app_server_protocol::ReasoningEffortOption;
+use codex_app_server_protocol::RequestId;
+use codex_protocol::config_types::ReasoningEffort;
+use pretty_assertions::assert_eq;
+use tempfile::TempDir;
+use tokio::time::timeout;
+
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
+const INVALID_REQUEST_ERROR_CODE: i64 = -32600;
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let request_id = mcp
+        .send_list_models_request(ListModelsParams {
+            page_size: Some(100),
+            cursor: None,
+        })
+        .await?;
+
+    let response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+
+    let ListModelsResponse { items, next_cursor } = to_response::<ListModelsResponse>(response)?;
+
+    let expected_models = vec![
+        Model {
+            id: "gpt-5-codex".to_string(),
+            model: "gpt-5-codex".to_string(),
+            display_name: "gpt-5-codex".to_string(),
+            description: "Optimized for coding tasks with many tools.".to_string(),
+            supported_reasoning_efforts: vec![
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::Low,
+                    description: "Fastest responses with limited reasoning".to_string(),
+                },
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::Medium,
+                    description: "Dynamically adjusts reasoning based on the task".to_string(),
+                },
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::High,
+                    description: "Maximizes reasoning depth for complex or ambiguous problems"
+                        .to_string(),
+                },
+            ],
+            default_reasoning_effort: ReasoningEffort::Medium,
+            is_default: true,
+        },
+        Model {
+            id: "gpt-5".to_string(),
+            model: "gpt-5".to_string(),
+            display_name: "gpt-5".to_string(),
+            description: "Broad world knowledge with strong general reasoning.".to_string(),
+            supported_reasoning_efforts: vec![
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::Minimal,
+                    description: "Fastest responses with little reasoning".to_string(),
+                },
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::Low,
+                    description: "Balances speed with some reasoning; useful for straightforward \
+                                   queries and short explanations"
+                        .to_string(),
+                },
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::Medium,
+                    description: "Provides a solid balance of reasoning depth and latency for \
+                         general-purpose tasks"
+                        .to_string(),
+                },
+                ReasoningEffortOption {
+                    reasoning_effort: ReasoningEffort::High,
+                    description: "Maximizes reasoning depth for complex or ambiguous problems"
+                        .to_string(),
+                },
+            ],
+            default_reasoning_effort: ReasoningEffort::Medium,
+            is_default: false,
+        },
+    ];
+
+    assert_eq!(items, expected_models);
+    assert!(next_cursor.is_none());
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn list_models_pagination_works() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let first_request = mcp
+        .send_list_models_request(ListModelsParams {
+            page_size: Some(1),
+            cursor: None,
+        })
+        .await?;
+
+    let first_response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(first_request)),
+    )
+    .await??;
+
+    let ListModelsResponse {
+        items: first_items,
+        next_cursor: first_cursor,
+    } = to_response::<ListModelsResponse>(first_response)?;
+
+    assert_eq!(first_items.len(), 1);
+    assert_eq!(first_items[0].id, "gpt-5-codex");
+    let next_cursor = first_cursor.ok_or_else(|| anyhow!("cursor for second page"))?;
+
+    let second_request = mcp
+        .send_list_models_request(ListModelsParams {
+            page_size: Some(1),
+            cursor: Some(next_cursor.clone()),
+        })
+        .await?;
+
+    let second_response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(second_request)),
+    )
+    .await??;
+
+    let ListModelsResponse {
+        items: second_items,
+        next_cursor: second_cursor,
+    } = to_response::<ListModelsResponse>(second_response)?;
+
+    assert_eq!(second_items.len(), 1);
+    assert_eq!(second_items[0].id, "gpt-5");
+    assert!(second_cursor.is_none());
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn list_models_rejects_invalid_cursor() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let request_id = mcp
+        .send_list_models_request(ListModelsParams {
+            page_size: None,
+            cursor: Some("invalid".to_string()),
+        })
+        .await?;
+
+    let error: JSONRPCError = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+
+    assert_eq!(error.id, RequestId::Integer(request_id));
+    assert_eq!(error.error.code, INVALID_REQUEST_ERROR_CODE);
+    assert_eq!(error.error.message, "invalid cursor: invalid");
+    Ok(())
+}

codex-rs/common/src/model_presets.rs

@@ -1,73 +1,96 @@
 use codex_app_server_protocol::AuthMode;
 use codex_core::protocol_config_types::ReasoningEffort;
 
-/// A simple preset pairing a model slug with a reasoning effort.
+/// A reasoning effort option that can be surfaced for a model.
+#[derive(Debug, Clone, Copy)]
+pub struct ReasoningEffortPreset {
+    /// Effort level that the model supports.
+    pub effort: ReasoningEffort,
+    /// Short human description shown next to the effort in UIs.
+    pub description: &'static str,
+}
+
+/// Metadata describing a Codex-supported model.
 #[derive(Debug, Clone, Copy)]
 pub struct ModelPreset {
     /// Stable identifier for the preset.
     pub id: &'static str,
-    /// Display label shown in UIs.
-    pub label: &'static str,
-    /// Short human description shown next to the label in UIs.
-    pub description: &'static str,
     /// Model slug (e.g., "gpt-5").
     pub model: &'static str,
-    /// Reasoning effort to apply for this preset.
-    pub effort: Option<ReasoningEffort>,
+    /// Display name shown in UIs.
+    pub display_name: &'static str,
+    /// Short human description shown in UIs.
+    pub description: &'static str,
+    /// Reasoning effort applied when none is explicitly chosen.
+    pub default_reasoning_effort: ReasoningEffort,
+    /// Supported reasoning effort options.
+    pub supported_reasoning_efforts: &'static [ReasoningEffortPreset],
+    /// Whether this is the default model for new users.
+    pub is_default: bool,
 }
 
 const PRESETS: &[ModelPreset] = &[
     ModelPreset {
-        id: "gpt-5-codex-low",
-        label: "gpt-5-codex low",
-        description: "Fastest responses with limited reasoning",
+        id: "gpt-5-codex",
         model: "gpt-5-codex",
-        effort: Some(ReasoningEffort::Low),
+        display_name: "gpt-5-codex",
+        description: "Optimized for coding tasks with many tools.",
+        default_reasoning_effort: ReasoningEffort::Medium,
+        supported_reasoning_efforts: &[
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::Low,
+                description: "Fastest responses with limited reasoning",
+            },
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::Medium,
+                description: "Dynamically adjusts reasoning based on the task",
+            },
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::High,
+                description: "Maximizes reasoning depth for complex or ambiguous problems",
+            },
+        ],
+        is_default: true,
     },
     ModelPreset {
-        id: "gpt-5-codex-medium",
-        label: "gpt-5-codex medium",
-        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: "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 little reasoning",
+        id: "gpt-5",
         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",
-        model: "gpt-5",
-        effort: Some(ReasoningEffort::Low),
-    },
-    ModelPreset {
-        id: "gpt-5-medium",
-        label: "gpt-5 medium",
-        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",
-        model: "gpt-5",
-        effort: Some(ReasoningEffort::High),
+        display_name: "gpt-5",
+        description: "Broad world knowledge with strong general reasoning.",
+        default_reasoning_effort: ReasoningEffort::Medium,
+        supported_reasoning_efforts: &[
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::Minimal,
+                description: "Fastest responses with little reasoning",
+            },
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::Low,
+                description: "Balances speed with some reasoning; useful for straightforward queries and short explanations",
+            },
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::Medium,
+                description: "Provides a solid balance of reasoning depth and latency for general-purpose tasks",
+            },
+            ReasoningEffortPreset {
+                effort: ReasoningEffort::High,
+                description: "Maximizes reasoning depth for complex or ambiguous problems",
+            },
+        ],
+        is_default: false,
     },
 ];
 
 pub fn builtin_model_presets(_auth_mode: Option<AuthMode>) -> Vec<ModelPreset> {
     PRESETS.to_vec()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn only_one_default_model_is_configured() {
+        let default_models = PRESETS.iter().filter(|preset| preset.is_default).count();
+        assert!(default_models == 1);
+    }
+}

codex-rs/docs/codex_mcp_interface.md

@@ -19,6 +19,7 @@ At a glance:
   - `listConversations`, `resumeConversation`, `archiveConversation`
 - Configuration and info
   - `getUserSavedConfig`, `setDefaultModel`, `getUserAgent`, `userInfo`
+  - `model/list` → enumerate available models and reasoning options
 - Auth
   - `loginApiKey`, `loginChatGpt`, `cancelLoginChatGpt`, `logoutChatGpt`, `getAuthStatus`
 - Utilities
@@ -73,6 +74,24 @@ Interrupt a running turn: `interruptConversation`.
 
 List/resume/archive: `listConversations`, `resumeConversation`, `archiveConversation`.
 
+## Models
+
+Fetch the catalog of models available in the current Codex build with `model/list`. The request accepts optional pagination inputs:
+
+- `pageSize` – number of models to return (defaults to a server-selected value)
+- `cursor` – opaque string from the previous response’s `nextCursor`
+
+Each response yields:
+
+- `items` – ordered list of models. A model includes:
+  - `id`, `model`, `displayName`, `description`
+  - `supportedReasoningEfforts` – array of objects with:
+    - `reasoningEffort` – one of `minimal|low|medium|high`
+    - `description` – human-friendly label for the effort
+  - `defaultReasoningEffort` – suggested effort for the UI
+  - `isDefault` – whether the model is recommended for most users
+- `nextCursor` – pass into the next request to continue paging (optional)
+
 ## Event stream
 
 While a conversation runs, the server sends notifications:

codex-rs/tui/src/app.rs

@@ -354,8 +354,8 @@ impl App {
                     self.config.model_family = family;
                 }
             }
-            AppEvent::OpenReasoningPopup { model, presets } => {
-                self.chat_widget.open_reasoning_popup(model, presets);
+            AppEvent::OpenReasoningPopup { model } => {
+                self.chat_widget.open_reasoning_popup(model);
             }
             AppEvent::OpenFullAccessConfirmation { preset } => {
                 self.chat_widget.open_full_access_confirmation(preset);

codex-rs/tui/src/app_event.rs

@@ -64,8 +64,7 @@ pub(crate) enum AppEvent {
 
     /// Open the reasoning selection popup after picking a model.
     OpenReasoningPopup {
-        model: String,
-        presets: Vec<ModelPreset>,
+        model: ModelPreset,
     },
 
     /// Open the confirmation prompt before enabling full access mode.

codex-rs/tui/src/chatwidget.rs

@@ -302,16 +302,6 @@ 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()
@@ -1661,39 +1651,22 @@ impl ChatWidget {
         let auth_mode = self.auth_manager.auth().map(|auth| auth.mode);
         let presets: Vec<ModelPreset> = builtin_model_presets(auth_mode);
 
-        let mut grouped: Vec<(&str, Vec<ModelPreset>)> = Vec::new();
-        for preset in presets.into_iter() {
-            if let Some((_, entries)) = grouped.iter_mut().find(|(model, _)| *model == preset.model)
-            {
-                entries.push(preset);
-            } else {
-                grouped.push((preset.model, vec![preset]));
-            }
-        }
-
         let mut items: Vec<SelectionItem> = Vec::new();
-        for (model_slug, entries) in grouped.into_iter() {
-            let name = model_slug.to_string();
-            let description = Self::model_description_for(model_slug)
-                .map(std::string::ToString::to_string)
-                .or_else(|| {
-                    entries
-                        .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();
+        for preset in presets.into_iter() {
+            let description = if preset.description.is_empty() {
+                None
+            } else {
+                Some(preset.description.to_string())
+            };
+            let is_current = preset.model == current_model;
+            let preset_for_action = preset;
             let actions: Vec<SelectionAction> = vec![Box::new(move |tx| {
                 tx.send(AppEvent::OpenReasoningPopup {
-                    model: model_slug_string.clone(),
-                    presets: presets_for_model.clone(),
+                    model: preset_for_action,
                 });
             })];
             items.push(SelectionItem {
-                name,
+                name: preset.display_name.to_string(),
                 description,
                 is_current,
                 actions,
@@ -1712,28 +1685,22 @@ impl ChatWidget {
     }
 
     /// 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();
+    pub(crate) fn open_reasoning_popup(&mut self, preset: ModelPreset) {
+        let default_effort: ReasoningEffortConfig = preset.default_reasoning_effort;
+        let supported = preset.supported_reasoning_efforts;
 
-        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)) {
+            if supported.iter().any(|option| option.effort == 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 {
@@ -1742,21 +1709,16 @@ impl ChatWidget {
             });
         }
 
-        let default_choice: Option<ReasoningEffortConfig> = if has_none_choice {
-            None
-        } else if choices
+        let default_choice: Option<ReasoningEffortConfig> = choices
             .iter()
             .any(|choice| choice.stored == Some(default_effort))
-        {
-            Some(default_effort)
-        } else {
-            choices
-                .iter()
-                .find_map(|choice| choice.stored)
-                .or(Some(default_effort))
-        };
+            .then_some(Some(default_effort))
+            .flatten()
+            .or_else(|| choices.iter().find_map(|choice| choice.stored))
+            .or(Some(default_effort));
 
-        let is_current_model = self.config.model == model_slug;
+        let model_slug = preset.model.to_string();
+        let is_current_model = self.config.model == preset.model;
         let highlight_choice = if is_current_model {
             self.config.model_reasoning_effort
         } else {
@@ -1773,19 +1735,19 @@ impl ChatWidget {
                 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
+            let description = choice
+                .stored
+                .and_then(|effort| {
+                    supported
                         .iter()
-                        .find(|preset| preset.effort == choice.stored)
-                        .map(|preset| preset.description.to_string())
-                });
+                        .find(|option| option.effort == effort)
+                        .map(|option| option.description.to_string())
+                })
+                .filter(|text| !text.is_empty());
 
             let warning = "⚠ High reasoning effort can quickly consume Plus plan rate limits.";
-            let show_warning = model_slug == "gpt-5-codex" && effort == ReasoningEffortConfig::High;
+            let show_warning =
+                preset.model == "gpt-5-codex" && effort == ReasoningEffortConfig::High;
             let selected_description = show_warning.then(|| {
                 description
                     .as_ref()

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

@@ -1122,11 +1122,11 @@ fn model_reasoning_selection_popup_snapshot() {
     chat.config.model = "gpt-5-codex".to_string();
     chat.config.model_reasoning_effort = Some(ReasoningEffortConfig::High);
 
-    let presets = builtin_model_presets(None)
+    let preset = 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);
+        .find(|preset| preset.model == "gpt-5-codex")
+        .expect("gpt-5-codex preset");
+    chat.open_reasoning_popup(preset);
 
     let popup = render_bottom_popup(&chat, 80);
     assert_snapshot!("model_reasoning_selection_popup", popup);
@@ -1141,9 +1141,9 @@ fn reasoning_popup_escape_returns_to_model_popup() {
 
     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);
+        .find(|preset| preset.model == "gpt-5-codex")
+        .expect("gpt-5-codex preset");
+    chat.open_reasoning_popup(presets);
 
     let before_escape = render_bottom_popup(&chat, 80);
     assert!(before_escape.contains("Select Reasoning Level"));