diff --git a/codex-rs/core/src/client.rs b/codex-rs/core/src/client.rs
index f4248f30a..a3c990cdb 100644
--- a/codex-rs/core/src/client.rs
+++ b/codex-rs/core/src/client.rs
@@ -46,10 +46,10 @@ use crate::default_client::build_reqwest_client;
 use crate::error::CodexErr;
 use crate::error::Result;
 use crate::flags::CODEX_RS_SSE_FIXTURE;
-use crate::model_family::ModelFamily;
 use crate::model_provider_info::ModelProviderInfo;
 use crate::model_provider_info::WireApi;
 use crate::openai_model_info::get_model_info;
+use crate::openai_models::model_family::ModelFamily;
 use crate::tools::spec::create_tools_json_for_chat_completions_api;
 use crate::tools::spec::create_tools_json_for_responses_api;
 
diff --git a/codex-rs/core/src/client_common.rs b/codex-rs/core/src/client_common.rs
index a249ca6fc..f6152e55d 100644
--- a/codex-rs/core/src/client_common.rs
+++ b/codex-rs/core/src/client_common.rs
@@ -1,6 +1,6 @@
 use crate::client_common::tools::ToolSpec;
 use crate::error::Result;
-use crate::model_family::ModelFamily;
+use crate::openai_models::model_family::ModelFamily;
 pub use codex_api::common::ResponseEvent;
 use codex_apply_patch::APPLY_PATCH_TOOL_INSTRUCTIONS;
 use codex_protocol::models::ResponseItem;
@@ -252,7 +252,7 @@ impl Stream for ResponseStream {
 
 #[cfg(test)]
 mod tests {
-    use crate::model_family::find_family_for_model;
+    use crate::openai_models::model_family::find_family_for_model;
     use codex_api::ResponsesApiRequest;
     use codex_api::common::OpenAiVerbosity;
     use codex_api::common::TextControls;
@@ -309,7 +309,7 @@ mod tests {
             },
         ];
         for test_case in test_cases {
-            let model_family = find_family_for_model(test_case.slug).expect("known model slug");
+            let model_family = find_family_for_model(test_case.slug);
             let expected = if test_case.expects_apply_patch_instructions {
                 format!(
                     "{}\n{}",
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 885a4cdf7..ba7c69eb9 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -14,6 +14,7 @@ use crate::compact_remote::run_inline_remote_auto_compact_task;
 use crate::features::Feature;
 use crate::features::Features;
 use crate::function_tool::FunctionCallError;
+use crate::openai_models::models_manager::ModelsManager;
 use crate::parse_command::parse_command;
 use crate::parse_turn_item;
 use crate::response_processing::process_items;
@@ -74,7 +75,6 @@ use crate::error::Result as CodexResult;
 use crate::exec::StreamOutput;
 use crate::mcp::auth::compute_auth_statuses;
 use crate::mcp_connection_manager::McpConnectionManager;
-use crate::model_family::find_family_for_model;
 use crate::openai_model_info::get_model_info;
 use crate::project_doc::get_user_instructions;
 use crate::protocol::AgentMessageContentDeltaEvent;
@@ -163,6 +163,7 @@ impl Codex {
     pub async fn spawn(
         config: Config,
         auth_manager: Arc<AuthManager>,
+        models_manager: Arc<ModelsManager>,
         conversation_history: InitialHistory,
         session_source: SessionSource,
     ) -> CodexResult<CodexSpawnOk> {
@@ -200,6 +201,7 @@ impl Codex {
             session_configuration,
             config.clone(),
             auth_manager.clone(),
+            models_manager.clone(),
             tx_event.clone(),
             conversation_history,
             session_source_clone,
@@ -394,6 +396,7 @@ pub(crate) struct SessionSettingsUpdate {
 impl Session {
     fn make_turn_context(
         auth_manager: Option<Arc<AuthManager>>,
+        models_manager: &ModelsManager,
         otel_event_manager: &OtelEventManager,
         provider: ModelProviderInfo,
         session_configuration: &SessionConfiguration,
@@ -402,8 +405,7 @@ impl Session {
     ) -> TurnContext {
         let config = session_configuration.original_config_do_not_use.clone();
         let features = &config.features;
-        let model_family = find_family_for_model(&session_configuration.model)
-            .unwrap_or_else(|| config.model_family.clone());
+        let model_family = models_manager.construct_model_family(&session_configuration.model);
         let mut per_turn_config = (*config).clone();
         per_turn_config.model = session_configuration.model.clone();
         per_turn_config.model_family = model_family.clone();
@@ -459,6 +461,7 @@ impl Session {
         session_configuration: SessionConfiguration,
         config: Arc<Config>,
         auth_manager: Arc<AuthManager>,
+        models_manager: Arc<ModelsManager>,
         tx_event: Sender<Event>,
         initial_history: InitialHistory,
         session_source: SessionSource,
@@ -570,6 +573,7 @@ impl Session {
             show_raw_agent_reasoning: config.show_raw_agent_reasoning,
             auth_manager: Arc::clone(&auth_manager),
             otel_event_manager,
+            models_manager: Arc::clone(&models_manager),
             tool_approvals: Mutex::new(ApprovalStore::default()),
         };
 
@@ -756,6 +760,7 @@ impl Session {
 
         let mut turn_context: TurnContext = Self::make_turn_context(
             Some(Arc::clone(&self.services.auth_manager)),
+            &self.services.models_manager,
             &self.services.otel_event_manager,
             session_configuration.provider.clone(),
             &session_configuration,
@@ -1824,8 +1829,7 @@ async fn spawn_review_thread(
     resolved: crate::review_prompts::ResolvedReviewRequest,
 ) {
     let model = config.review_model.clone();
-    let review_model_family = find_family_for_model(&model)
-        .unwrap_or_else(|| parent_turn_context.client.get_model_family());
+    let review_model_family = sess.services.models_manager.construct_model_family(&model);
     // For reviews, disable web_search and view_image regardless of global settings.
     let mut review_features = sess.features.clone();
     review_features
@@ -2083,13 +2087,13 @@ async fn run_turn(
     let mut base_instructions = turn_context.base_instructions.clone();
     if parallel_tool_calls {
         static INSTRUCTIONS: &str = include_str!("../templates/parallel/instructions.md");
-        if let Some(family) =
-            find_family_for_model(&sess.state.lock().await.session_configuration.model)
-        {
-            let mut new_instructions = base_instructions.unwrap_or(family.base_instructions);
-            new_instructions.push_str(INSTRUCTIONS);
-            base_instructions = Some(new_instructions);
-        }
+        let family = sess
+            .services
+            .models_manager
+            .construct_model_family(&sess.state.lock().await.session_configuration.model);
+        let mut new_instructions = base_instructions.unwrap_or(family.base_instructions);
+        new_instructions.push_str(INSTRUCTIONS);
+        base_instructions = Some(new_instructions);
     }
     let prompt = Prompt {
         input,
@@ -2751,6 +2755,7 @@ mod tests {
             false,
             config.cli_auth_credentials_store_mode,
         );
+        let models_manager = Arc::new(ModelsManager::new(auth_manager.get_auth_mode()));
 
         let session_configuration = SessionConfiguration {
             provider: config.model_provider.clone(),
@@ -2781,11 +2786,13 @@ mod tests {
             show_raw_agent_reasoning: config.show_raw_agent_reasoning,
             auth_manager: Arc::clone(&auth_manager),
             otel_event_manager: otel_event_manager.clone(),
+            models_manager: models_manager.clone(),
             tool_approvals: Mutex::new(ApprovalStore::default()),
         };
 
         let turn_context = Session::make_turn_context(
             Some(Arc::clone(&auth_manager)),
+            &models_manager,
             &otel_event_manager,
             session_configuration.provider.clone(),
             &session_configuration,
@@ -2829,6 +2836,7 @@ mod tests {
             false,
             config.cli_auth_credentials_store_mode,
         );
+        let models_manager = Arc::new(ModelsManager::new(auth_manager.get_auth_mode()));
 
         let session_configuration = SessionConfiguration {
             provider: config.model_provider.clone(),
@@ -2859,11 +2867,13 @@ mod tests {
             show_raw_agent_reasoning: config.show_raw_agent_reasoning,
             auth_manager: Arc::clone(&auth_manager),
             otel_event_manager: otel_event_manager.clone(),
+            models_manager: models_manager.clone(),
             tool_approvals: Mutex::new(ApprovalStore::default()),
         };
 
         let turn_context = Arc::new(Session::make_turn_context(
             Some(Arc::clone(&auth_manager)),
+            &models_manager,
             &otel_event_manager,
             session_configuration.provider.clone(),
             &session_configuration,
diff --git a/codex-rs/core/src/codex_delegate.rs b/codex-rs/core/src/codex_delegate.rs
index 796331d1e..b6e4c88f3 100644
--- a/codex-rs/core/src/codex_delegate.rs
+++ b/codex-rs/core/src/codex_delegate.rs
@@ -25,6 +25,7 @@ use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::config::Config;
 use crate::error::CodexErr;
+use crate::openai_models::models_manager::ModelsManager;
 use codex_protocol::protocol::InitialHistory;
 
 /// Start an interactive sub-Codex conversation and return IO channels.
@@ -35,6 +36,7 @@ use codex_protocol::protocol::InitialHistory;
 pub(crate) async fn run_codex_conversation_interactive(
     config: Config,
     auth_manager: Arc<AuthManager>,
+    models_manager: Arc<ModelsManager>,
     parent_session: Arc<Session>,
     parent_ctx: Arc<TurnContext>,
     cancel_token: CancellationToken,
@@ -46,6 +48,7 @@ pub(crate) async fn run_codex_conversation_interactive(
     let CodexSpawnOk { codex, .. } = Codex::spawn(
         config,
         auth_manager,
+        models_manager,
         initial_history.unwrap_or(InitialHistory::New),
         SessionSource::SubAgent(SubAgentSource::Review),
     )
@@ -88,9 +91,11 @@ pub(crate) async fn run_codex_conversation_interactive(
 /// Convenience wrapper for one-time use with an initial prompt.
 ///
 /// Internally calls the interactive variant, then immediately submits the provided input.
+#[allow(clippy::too_many_arguments)]
 pub(crate) async fn run_codex_conversation_one_shot(
     config: Config,
     auth_manager: Arc<AuthManager>,
+    models_manager: Arc<ModelsManager>,
     input: Vec<UserInput>,
     parent_session: Arc<Session>,
     parent_ctx: Arc<TurnContext>,
@@ -103,6 +108,7 @@ pub(crate) async fn run_codex_conversation_one_shot(
     let io = run_codex_conversation_interactive(
         config,
         auth_manager,
+        models_manager,
         parent_session,
         parent_ctx,
         child_cancel.clone(),
diff --git a/codex-rs/core/src/config/mod.rs b/codex-rs/core/src/config/mod.rs
index dccf0556f..185584115 100644
--- a/codex-rs/core/src/config/mod.rs
+++ b/codex-rs/core/src/config/mod.rs
@@ -22,14 +22,13 @@ use crate::features::FeatureOverrides;
 use crate::features::Features;
 use crate::features::FeaturesToml;
 use crate::git_info::resolve_root_git_project_for_trust;
-use crate::model_family::ModelFamily;
-use crate::model_family::derive_default_model_family;
-use crate::model_family::find_family_for_model;
 use crate::model_provider_info::LMSTUDIO_OSS_PROVIDER_ID;
 use crate::model_provider_info::ModelProviderInfo;
 use crate::model_provider_info::OLLAMA_OSS_PROVIDER_ID;
 use crate::model_provider_info::built_in_model_providers;
 use crate::openai_model_info::get_model_info;
+use crate::openai_models::model_family::ModelFamily;
+use crate::openai_models::model_family::find_family_for_model;
 use crate::project_doc::DEFAULT_PROJECT_DOC_FILENAME;
 use crate::project_doc::LOCAL_PROJECT_DOC_FILENAME;
 use crate::protocol::AskForApproval;
@@ -82,6 +81,7 @@ pub struct Config {
     /// Model used specifically for review sessions. Defaults to "gpt-5.1-codex-max".
     pub review_model: String,
 
+    // todo(aibrahim): remove this field
     pub model_family: ModelFamily,
 
     /// Size of the context window for the model, in tokens.
@@ -1109,8 +1109,7 @@ impl Config {
             .or(cfg.model)
             .unwrap_or_else(default_model);
 
-        let mut model_family =
-            find_family_for_model(&model).unwrap_or_else(|| derive_default_model_family(&model));
+        let mut model_family = find_family_for_model(&model);
 
         if let Some(supports_reasoning_summaries) = cfg.model_supports_reasoning_summaries {
             model_family.supports_reasoning_summaries = supports_reasoning_summaries;
@@ -2955,7 +2954,7 @@ model_verbosity = "high"
             Config {
                 model: "o3".to_string(),
                 review_model: OPENAI_DEFAULT_REVIEW_MODEL.to_string(),
-                model_family: find_family_for_model("o3").expect("known model slug"),
+                model_family: find_family_for_model("o3"),
                 model_context_window: Some(200_000),
                 model_auto_compact_token_limit: Some(180_000),
                 model_provider_id: "openai".to_string(),
@@ -3029,7 +3028,7 @@ model_verbosity = "high"
         let expected_gpt3_profile_config = Config {
             model: "gpt-3.5-turbo".to_string(),
             review_model: OPENAI_DEFAULT_REVIEW_MODEL.to_string(),
-            model_family: find_family_for_model("gpt-3.5-turbo").expect("known model slug"),
+            model_family: find_family_for_model("gpt-3.5-turbo"),
             model_context_window: Some(16_385),
             model_auto_compact_token_limit: Some(14_746),
             model_provider_id: "openai-chat-completions".to_string(),
@@ -3118,7 +3117,7 @@ model_verbosity = "high"
         let expected_zdr_profile_config = Config {
             model: "o3".to_string(),
             review_model: OPENAI_DEFAULT_REVIEW_MODEL.to_string(),
-            model_family: find_family_for_model("o3").expect("known model slug"),
+            model_family: find_family_for_model("o3"),
             model_context_window: Some(200_000),
             model_auto_compact_token_limit: Some(180_000),
             model_provider_id: "openai".to_string(),
@@ -3193,7 +3192,7 @@ model_verbosity = "high"
         let expected_gpt5_profile_config = Config {
             model: "gpt-5.1".to_string(),
             review_model: OPENAI_DEFAULT_REVIEW_MODEL.to_string(),
-            model_family: find_family_for_model("gpt-5.1").expect("known model slug"),
+            model_family: find_family_for_model("gpt-5.1"),
             model_context_window: Some(272_000),
             model_auto_compact_token_limit: Some(244_800),
             model_provider_id: "openai".to_string(),
diff --git a/codex-rs/core/src/conversation_manager.rs b/codex-rs/core/src/conversation_manager.rs
index f41e5b597..22f73dfe1 100644
--- a/codex-rs/core/src/conversation_manager.rs
+++ b/codex-rs/core/src/conversation_manager.rs
@@ -65,14 +65,19 @@ impl ConversationManager {
     }
 
     pub async fn new_conversation(&self, config: Config) -> CodexResult<NewConversation> {
-        self.spawn_conversation(config, self.auth_manager.clone())
-            .await
+        self.spawn_conversation(
+            config,
+            self.auth_manager.clone(),
+            self.models_manager.clone(),
+        )
+        .await
     }
 
     async fn spawn_conversation(
         &self,
         config: Config,
         auth_manager: Arc<AuthManager>,
+        models_manager: Arc<ModelsManager>,
     ) -> CodexResult<NewConversation> {
         let CodexSpawnOk {
             codex,
@@ -80,6 +85,7 @@ impl ConversationManager {
         } = Codex::spawn(
             config,
             auth_manager,
+            models_manager,
             InitialHistory::New,
             self.session_source.clone(),
         )
@@ -156,6 +162,7 @@ impl ConversationManager {
         } = Codex::spawn(
             config,
             auth_manager,
+            self.models_manager.clone(),
             initial_history,
             self.session_source.clone(),
         )
@@ -193,7 +200,14 @@ impl ConversationManager {
         let CodexSpawnOk {
             codex,
             conversation_id,
-        } = Codex::spawn(config, auth_manager, history, self.session_source.clone()).await?;
+        } = Codex::spawn(
+            config,
+            auth_manager,
+            self.models_manager.clone(),
+            history,
+            self.session_source.clone(),
+        )
+        .await?;
 
         self.finalize_spawn(codex, conversation_id).await
     }
diff --git a/codex-rs/core/src/lib.rs b/codex-rs/core/src/lib.rs
index d32366476..39dc224dd 100644
--- a/codex-rs/core/src/lib.rs
+++ b/codex-rs/core/src/lib.rs
@@ -67,7 +67,6 @@ pub use conversation_manager::NewConversation;
 pub use auth::AuthManager;
 pub use auth::CodexAuth;
 pub mod default_client;
-pub mod model_family;
 mod openai_model_info;
 pub mod project_doc;
 mod rollout;
diff --git a/codex-rs/core/src/openai_model_info.rs b/codex-rs/core/src/openai_model_info.rs
index 96f3ed77c..4ee7d7187 100644
--- a/codex-rs/core/src/openai_model_info.rs
+++ b/codex-rs/core/src/openai_model_info.rs
@@ -1,4 +1,4 @@
-use crate::model_family::ModelFamily;
+use crate::openai_models::model_family::ModelFamily;
 
 // Shared constants for commonly used window/token sizes.
 pub(crate) const CONTEXT_WINDOW_272K: i64 = 272_000;
diff --git a/codex-rs/core/src/openai_models/mod.rs b/codex-rs/core/src/openai_models/mod.rs
index 13ee2e060..e7a8beddb 100644
--- a/codex-rs/core/src/openai_models/mod.rs
+++ b/codex-rs/core/src/openai_models/mod.rs
@@ -1,2 +1,3 @@
+pub mod model_family;
 pub mod model_presets;
 pub mod models_manager;
diff --git a/codex-rs/core/src/model_family.rs b/codex-rs/core/src/openai_models/model_family.rs
similarity index 95%
rename from codex-rs/core/src/model_family.rs
rename to codex-rs/core/src/openai_models/model_family.rs
index 0417f13b1..1580ab137 100644
--- a/codex-rs/core/src/model_family.rs
+++ b/codex-rs/core/src/openai_models/model_family.rs
@@ -8,11 +8,11 @@ use crate::truncate::TruncationPolicy;
 
 /// The `instructions` field in the payload sent to a model should always start
 /// with this content.
-const BASE_INSTRUCTIONS: &str = include_str!("../prompt.md");
+const BASE_INSTRUCTIONS: &str = include_str!("../../prompt.md");
 
-const GPT_5_CODEX_INSTRUCTIONS: &str = include_str!("../gpt_5_codex_prompt.md");
-const GPT_5_1_INSTRUCTIONS: &str = include_str!("../gpt_5_1_prompt.md");
-const GPT_5_1_CODEX_MAX_INSTRUCTIONS: &str = include_str!("../gpt-5.1-codex-max_prompt.md");
+const GPT_5_CODEX_INSTRUCTIONS: &str = include_str!("../../gpt_5_codex_prompt.md");
+const GPT_5_1_INSTRUCTIONS: &str = include_str!("../../gpt_5_1_prompt.md");
+const GPT_5_1_CODEX_MAX_INSTRUCTIONS: &str = include_str!("../../gpt-5.1-codex-max_prompt.md");
 
 /// A model family is a group of models that share certain characteristics.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -100,13 +100,14 @@ macro_rules! model_family {
         $(
             mf.$key = $value;
         )*
-        Some(mf)
+        mf
     }};
 }
 
+// todo(aibrahim): remove this function
 /// Returns a `ModelFamily` for the given model slug, or `None` if the slug
 /// does not match any known model family.
-pub fn find_family_for_model(slug: &str) -> Option<ModelFamily> {
+pub fn find_family_for_model(slug: &str) -> ModelFamily {
     if slug.starts_with("o3") {
         model_family!(
             slug, "o3",
@@ -238,11 +239,11 @@ pub fn find_family_for_model(slug: &str) -> Option<ModelFamily> {
             truncation_policy: TruncationPolicy::Bytes(10_000),
         )
     } else {
-        None
+        derive_default_model_family(slug)
     }
 }
 
-pub fn derive_default_model_family(model: &str) -> ModelFamily {
+fn derive_default_model_family(model: &str) -> ModelFamily {
     ModelFamily {
         slug: model.to_string(),
         family: model.to_string(),
diff --git a/codex-rs/core/src/openai_models/models_manager.rs b/codex-rs/core/src/openai_models/models_manager.rs
index 1d57f1e69..c6f936542 100644
--- a/codex-rs/core/src/openai_models/models_manager.rs
+++ b/codex-rs/core/src/openai_models/models_manager.rs
@@ -2,6 +2,8 @@ use codex_app_server_protocol::AuthMode;
 use codex_protocol::openai_models::ModelPreset;
 use tokio::sync::RwLock;
 
+use crate::openai_models::model_family::ModelFamily;
+use crate::openai_models::model_family::find_family_for_model;
 use crate::openai_models::model_presets::builtin_model_presets;
 
 pub struct ModelsManager {
@@ -23,4 +25,8 @@ impl ModelsManager {
         let models = builtin_model_presets(self.auth_mode);
         *self.available_models.write().await = models;
     }
+
+    pub fn construct_model_family(&self, model: &str) -> ModelFamily {
+        find_family_for_model(model)
+    }
 }
diff --git a/codex-rs/core/src/state/service.rs b/codex-rs/core/src/state/service.rs
index 287fb73d2..a35720a9b 100644
--- a/codex-rs/core/src/state/service.rs
+++ b/codex-rs/core/src/state/service.rs
@@ -3,6 +3,7 @@ use std::sync::Arc;
 use crate::AuthManager;
 use crate::RolloutRecorder;
 use crate::mcp_connection_manager::McpConnectionManager;
+use crate::openai_models::models_manager::ModelsManager;
 use crate::tools::sandboxing::ApprovalStore;
 use crate::unified_exec::UnifiedExecSessionManager;
 use crate::user_notification::UserNotifier;
@@ -20,6 +21,7 @@ pub(crate) struct SessionServices {
     pub(crate) user_shell: crate::shell::Shell,
     pub(crate) show_raw_agent_reasoning: bool,
     pub(crate) auth_manager: Arc<AuthManager>,
+    pub(crate) models_manager: Arc<ModelsManager>,
     pub(crate) otel_event_manager: OtelEventManager,
     pub(crate) tool_approvals: Mutex<ApprovalStore>,
 }
diff --git a/codex-rs/core/src/tasks/mod.rs b/codex-rs/core/src/tasks/mod.rs
index 9bda02c34..fa5433ef5 100644
--- a/codex-rs/core/src/tasks/mod.rs
+++ b/codex-rs/core/src/tasks/mod.rs
@@ -19,6 +19,7 @@ use tracing::warn;
 use crate::AuthManager;
 use crate::codex::Session;
 use crate::codex::TurnContext;
+use crate::openai_models::models_manager::ModelsManager;
 use crate::protocol::EventMsg;
 use crate::protocol::TaskCompleteEvent;
 use crate::protocol::TurnAbortReason;
@@ -55,6 +56,10 @@ impl SessionTaskContext {
     pub(crate) fn auth_manager(&self) -> Arc<AuthManager> {
         Arc::clone(&self.session.services.auth_manager)
     }
+
+    pub(crate) fn models_manager(&self) -> Arc<ModelsManager> {
+        Arc::clone(&self.session.services.models_manager)
+    }
 }
 
 /// Async task that drives a [`Session`] turn.
diff --git a/codex-rs/core/src/tasks/review.rs b/codex-rs/core/src/tasks/review.rs
index a6ec840a8..738d33c52 100644
--- a/codex-rs/core/src/tasks/review.rs
+++ b/codex-rs/core/src/tasks/review.rs
@@ -93,6 +93,7 @@ async fn start_review_conversation(
     (run_codex_conversation_one_shot(
         sub_agent_config,
         session.auth_manager(),
+        session.models_manager(),
         input,
         session.clone_session(),
         ctx.clone(),
diff --git a/codex-rs/core/src/tools/spec.rs b/codex-rs/core/src/tools/spec.rs
index d07c605e5..2c3aa2d44 100644
--- a/codex-rs/core/src/tools/spec.rs
+++ b/codex-rs/core/src/tools/spec.rs
@@ -2,7 +2,7 @@ use crate::client_common::tools::ResponsesApiTool;
 use crate::client_common::tools::ToolSpec;
 use crate::features::Feature;
 use crate::features::Features;
-use crate::model_family::ModelFamily;
+use crate::openai_models::model_family::ModelFamily;
 use crate::tools::handlers::PLAN_TOOL;
 use crate::tools::handlers::apply_patch::ApplyPatchToolType;
 use crate::tools::handlers::apply_patch::create_apply_patch_freeform_tool;
@@ -1118,7 +1118,7 @@ pub(crate) fn build_specs(
 #[cfg(test)]
 mod tests {
     use crate::client_common::tools::FreeformTool;
-    use crate::model_family::find_family_for_model;
+    use crate::openai_models::model_family::find_family_for_model;
     use crate::tools::registry::ConfiguredToolSpec;
     use mcp_types::ToolInputSchema;
     use pretty_assertions::assert_eq;
@@ -1213,8 +1213,7 @@ mod tests {
 
     #[test]
     fn test_full_toolset_specs_for_gpt5_codex_unified_exec_web_search() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1273,8 +1272,7 @@ mod tests {
     }
 
     fn assert_model_tools(model_family: &str, features: &Features, expected_tools: &[&str]) {
-        let model_family = find_family_for_model(model_family)
-            .unwrap_or_else(|| panic!("{model_family} should be a valid model family"));
+        let model_family = find_family_for_model(model_family);
         let config = ToolsConfig::new(&ToolsConfigParams {
             model_family: &model_family,
             features,
@@ -1466,7 +1464,7 @@ mod tests {
 
     #[test]
     fn test_build_specs_default_shell_present() {
-        let model_family = find_family_for_model("o3").expect("o3 should be a valid model family");
+        let model_family = find_family_for_model("o3");
         let mut features = Features::with_defaults();
         features.enable(Feature::WebSearchRequest);
         features.enable(Feature::UnifiedExec);
@@ -1487,8 +1485,7 @@ mod tests {
     #[test]
     #[ignore]
     fn test_parallel_support_flags() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("codex-mini-latest should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.disable(Feature::ViewImageTool);
         features.enable(Feature::UnifiedExec);
@@ -1507,8 +1504,7 @@ mod tests {
 
     #[test]
     fn test_test_model_family_includes_sync_tool() {
-        let model_family = find_family_for_model("test-gpt-5-codex")
-            .expect("test-gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("test-gpt-5-codex");
         let mut features = Features::with_defaults();
         features.disable(Feature::ViewImageTool);
         let config = ToolsConfig::new(&ToolsConfigParams {
@@ -1537,7 +1533,7 @@ mod tests {
 
     #[test]
     fn test_build_specs_mcp_tools_converted() {
-        let model_family = find_family_for_model("o3").expect("o3 should be a valid model family");
+        let model_family = find_family_for_model("o3");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1631,7 +1627,7 @@ mod tests {
 
     #[test]
     fn test_build_specs_mcp_tools_sorted_by_name() {
-        let model_family = find_family_for_model("o3").expect("o3 should be a valid model family");
+        let model_family = find_family_for_model("o3");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         let config = ToolsConfig::new(&ToolsConfigParams {
@@ -1706,8 +1702,7 @@ mod tests {
 
     #[test]
     fn test_mcp_tool_property_missing_type_defaults_to_string() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1763,8 +1758,7 @@ mod tests {
 
     #[test]
     fn test_mcp_tool_integer_normalized_to_number() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1816,8 +1810,7 @@ mod tests {
 
     #[test]
     fn test_mcp_tool_array_without_items_gets_default_string_items() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1873,8 +1866,7 @@ mod tests {
 
     #[test]
     fn test_mcp_tool_anyof_defaults_to_string() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
@@ -1985,8 +1977,7 @@ Examples of valid command strings:
 
     #[test]
     fn test_get_openai_tools_mcp_tools_with_additional_properties_schema() {
-        let model_family = find_family_for_model("gpt-5-codex")
-            .expect("gpt-5-codex should be a valid model family");
+        let model_family = find_family_for_model("gpt-5-codex");
         let mut features = Features::with_defaults();
         features.enable(Feature::UnifiedExec);
         features.enable(Feature::WebSearchRequest);
diff --git a/codex-rs/core/tests/common/test_codex.rs b/codex-rs/core/tests/common/test_codex.rs
index 1c5919214..aff2ab60d 100644
--- a/codex-rs/core/tests/common/test_codex.rs
+++ b/codex-rs/core/tests/common/test_codex.rs
@@ -11,7 +11,6 @@ use codex_core::ModelProviderInfo;
 use codex_core::built_in_model_providers;
 use codex_core::config::Config;
 use codex_core::features::Feature;
-use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::Op;
@@ -71,7 +70,6 @@ impl TestCodexBuilder {
         let new_model = model.to_string();
         self.with_config(move |config| {
             config.model = new_model.clone();
-            config.model_family = find_family_for_model(&new_model).expect("model family");
         })
     }
 
diff --git a/codex-rs/core/tests/suite/client.rs b/codex-rs/core/tests/suite/client.rs
index e0e06757b..e5d3d7e61 100644
--- a/codex-rs/core/tests/suite/client.rs
+++ b/codex-rs/core/tests/suite/client.rs
@@ -16,7 +16,7 @@ use codex_core::auth::AuthCredentialsStoreMode;
 use codex_core::built_in_model_providers;
 use codex_core::error::CodexErr;
 use codex_core::features::Feature;
-use codex_core::model_family::find_family_for_model;
+use codex_core::openai_models::model_family::find_family_for_model;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::Op;
 use codex_core::protocol::SessionSource;
@@ -1378,8 +1378,7 @@ async fn context_window_error_sets_total_tokens_to_model_window() -> anyhow::Res
     let TestCodex { codex, .. } = test_codex()
         .with_config(|config| {
             config.model = "gpt-5.1".to_string();
-            config.model_family =
-                find_family_for_model("gpt-5.1").expect("known gpt-5.1 model family");
+            config.model_family = find_family_for_model("gpt-5.1");
             config.model_context_window = Some(272_000);
         })
         .build(&server)
diff --git a/codex-rs/core/tests/suite/prompt_caching.rs b/codex-rs/core/tests/suite/prompt_caching.rs
index 0c908e35b..219f29e2f 100644
--- a/codex-rs/core/tests/suite/prompt_caching.rs
+++ b/codex-rs/core/tests/suite/prompt_caching.rs
@@ -1,7 +1,7 @@
 #![allow(clippy::unwrap_used)]
 
 use codex_core::features::Feature;
-use codex_core::model_family::find_family_for_model;
+use codex_core::openai_models::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
 use codex_core::protocol::ENVIRONMENT_CONTEXT_OPEN_TAG;
 use codex_core::protocol::EventMsg;
@@ -74,7 +74,6 @@ async fn codex_mini_latest_tools() -> anyhow::Result<()> {
             config.features.disable(Feature::ApplyPatchFreeform);
             config.model = "codex-mini-latest".to_string();
             config.model_family = find_family_for_model("codex-mini-latest")
-                .expect("model family for codex-mini-latest");
         })
         .build(&server)
         .await?;
diff --git a/codex-rs/core/tests/suite/shell_serialization.rs b/codex-rs/core/tests/suite/shell_serialization.rs
index 77c835b32..5dbdda4fc 100644
--- a/codex-rs/core/tests/suite/shell_serialization.rs
+++ b/codex-rs/core/tests/suite/shell_serialization.rs
@@ -4,7 +4,7 @@
 use anyhow::Result;
 use codex_core::config::Config;
 use codex_core::features::Feature;
-use codex_core::model_family::find_family_for_model;
+use codex_core::openai_models::model_family::find_family_for_model;
 use codex_core::protocol::SandboxPolicy;
 use core_test_support::assert_regex_match;
 use core_test_support::responses::ev_assistant_message;
@@ -46,13 +46,12 @@ fn configure_shell_command_model(output_type: ShellModelOutput, config: &mut Con
         return;
     }
 
-    if let Some(shell_command_family) = find_family_for_model("test-gpt-5-codex") {
-        if config.model_family.shell_type == shell_command_family.shell_type {
-            return;
-        }
-        config.model = shell_command_family.slug.clone();
-        config.model_family = shell_command_family;
+    let shell_command_family = find_family_for_model("test-gpt-5-codex");
+    if config.model_family.shell_type == shell_command_family.shell_type {
+        return;
     }
+    config.model = shell_command_family.slug.clone();
+    config.model_family = shell_command_family;
 }
 
 fn shell_responses(
diff --git a/codex-rs/tui/src/app.rs b/codex-rs/tui/src/app.rs
index 2367bbd58..ff5fe9a54 100644
--- a/codex-rs/tui/src/app.rs
+++ b/codex-rs/tui/src/app.rs
@@ -26,7 +26,7 @@ use codex_core::ConversationManager;
 use codex_core::config::Config;
 use codex_core::config::edit::ConfigEditsBuilder;
 use codex_core::features::Feature;
-use codex_core::model_family::find_family_for_model;
+use codex_core::openai_models::model_family::find_family_for_model;
 use codex_core::openai_models::model_presets::HIDE_GPT_5_1_CODEX_MAX_MIGRATION_PROMPT_CONFIG;
 use codex_core::openai_models::model_presets::HIDE_GPT5_1_MIGRATION_PROMPT_CONFIG;
 use codex_core::openai_models::models_manager::ModelsManager;
@@ -162,9 +162,7 @@ async fn handle_model_migration_prompt_if_needed(
                     migration_config: migration_config_key.to_string(),
                 });
                 config.model = target_model.to_string();
-                if let Some(family) = find_family_for_model(&target_model) {
-                    config.model_family = family;
-                }
+                config.model_family = find_family_for_model(&target_model);
 
                 let mapped_effort = if let Some(reasoning_effort_mapping) = reasoning_effort_mapping
                     && let Some(reasoning_effort) = config.model_reasoning_effort
@@ -683,9 +681,8 @@ impl App {
             AppEvent::UpdateModel(model) => {
                 self.chat_widget.set_model(&model);
                 self.config.model = model.clone();
-                if let Some(family) = find_family_for_model(&model) {
-                    self.config.model_family = family;
-                }
+                let family = find_family_for_model(&model);
+                self.config.model_family = family;
             }
             AppEvent::OpenReasoningPopup { model } => {
                 self.chat_widget.open_reasoning_popup(model);