diff --git a/codex-rs/core/tests/suite/mod.rs b/codex-rs/core/tests/suite/mod.rs
index f4ab6c1d6d..51a5bea57f 100644
--- a/codex-rs/core/tests/suite/mod.rs
+++ b/codex-rs/core/tests/suite/mod.rs
@@ -63,6 +63,7 @@ mod json_result;
 mod live_cli;
 mod mcp_turn_metadata;
 mod model_overrides;
+mod model_runtime_selectors;
 mod model_switching;
 mod model_visible_layout;
 mod models_cache_ttl;
diff --git a/codex-rs/core/tests/suite/model_runtime_selectors.rs b/codex-rs/core/tests/suite/model_runtime_selectors.rs
new file mode 100644
index 0000000000..55d42604cc
--- /dev/null
+++ b/codex-rs/core/tests/suite/model_runtime_selectors.rs
@@ -0,0 +1,156 @@
+use anyhow::Result;
+use codex_core::config::Config;
+use codex_features::Feature;
+use codex_login::CodexAuth;
+use codex_models_manager::manager::RefreshStrategy;
+use codex_models_manager::manager::SharedModelsManager;
+use codex_models_manager::model_info::model_info_from_slug;
+use codex_protocol::openai_models::ModelInfo;
+use codex_protocol::openai_models::ModelPreset;
+use codex_protocol::openai_models::ModelVisibility;
+use codex_protocol::openai_models::ModelsResponse;
+use codex_protocol::openai_models::ToolMode;
+use codex_protocol::protocol::ThreadSettingsOverrides;
+use core_test_support::responses;
+use core_test_support::responses::ev_assistant_message;
+use core_test_support::responses::ev_completed;
+use core_test_support::responses::ev_response_created;
+use core_test_support::responses::mount_models_once;
+use core_test_support::responses::mount_sse_once;
+use core_test_support::responses::sse;
+use core_test_support::skip_if_no_network;
+use core_test_support::submit_thread_settings;
+use core_test_support::test_codex::test_codex;
+use pretty_assertions::assert_eq;
+use serde_json::Value;
+use tokio::time::Duration;
+use tokio::time::Instant;
+use tokio::time::sleep;
+
+fn remote_model(slug: &str) -> ModelInfo {
+    ModelInfo {
+        visibility: ModelVisibility::List,
+        used_fallback_model_metadata: false,
+        ..model_info_from_slug(slug)
+    }
+}
+
+fn tool_names(body: &Value) -> Vec<String> {
+    body.get("tools")
+        .and_then(Value::as_array)
+        .map(|tools| {
+            tools
+                .iter()
+                .filter_map(|tool| {
+                    tool.get("name")
+                        .or_else(|| tool.get("type"))
+                        .and_then(Value::as_str)
+                        .map(str::to_string)
+                })
+                .collect()
+        })
+        .unwrap_or_default()
+}
+
+async fn wait_for_model_available(manager: &SharedModelsManager, slug: &str) -> ModelPreset {
+    let deadline = Instant::now() + Duration::from_secs(2);
+    loop {
+        if let Some(model) = manager
+            .list_models(RefreshStrategy::OnlineIfUncached)
+            .await
+            .iter()
+            .find(|model| model.model == slug)
+            .cloned()
+        {
+            return model;
+        }
+        if Instant::now() >= deadline {
+            panic!("timed out waiting for the remote model {slug} to appear");
+        }
+        sleep(Duration::from_millis(25)).await;
+    }
+}
+
+async fn tools_for_remote_model(
+    remote_model: ModelInfo,
+    configure: impl FnOnce(&mut Config) + Send + 'static,
+) -> Result<Vec<String>> {
+    let server = responses::start_mock_server().await;
+    let model_slug = remote_model.slug.clone();
+    let models_mock = mount_models_once(
+        &server,
+        ModelsResponse {
+            models: vec![remote_model],
+        },
+    )
+    .await;
+    let response_mock = mount_sse_once(
+        &server,
+        sse(vec![
+            ev_response_created("resp-1"),
+            ev_assistant_message("msg-1", "done"),
+            ev_completed("resp-1"),
+        ]),
+    )
+    .await;
+
+    let mut builder = test_codex()
+        .with_auth(CodexAuth::create_dummy_chatgpt_auth_for_testing())
+        .with_config(configure);
+    let test = builder.build(&server).await?;
+    let models_manager = test.thread_manager.get_models_manager();
+    let available_model = wait_for_model_available(&models_manager, &model_slug).await;
+    assert_eq!(available_model.model, model_slug);
+    assert_eq!(models_mock.requests().len(), 1);
+
+    submit_thread_settings(
+        &test.codex,
+        ThreadSettingsOverrides {
+            model: Some(model_slug),
+            ..Default::default()
+        },
+    )
+    .await?;
+    test.submit_turn("list tools").await?;
+
+    Ok(tool_names(&response_mock.single_request().body_json()))
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn remote_tool_mode_selector_overrides_feature_flags() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let mut direct_model = remote_model("test-tool-mode-direct");
+    direct_model.tool_mode = Some(ToolMode::Direct);
+    let direct_tools = tools_for_remote_model(direct_model, |config| {
+        config
+            .features
+            .enable(Feature::CodeModeOnly)
+            .expect("test config should allow feature update");
+    })
+    .await?;
+    assert!(
+        direct_tools.iter().any(|name| name == "shell_command"),
+        "direct mode should retain shell_command: {direct_tools:?}"
+    );
+    assert!(
+        direct_tools
+            .iter()
+            .all(|name| name != codex_code_mode::PUBLIC_TOOL_NAME
+                && name != codex_code_mode::WAIT_TOOL_NAME),
+        "direct mode should override enabled code mode flags: {direct_tools:?}"
+    );
+
+    let mut code_mode_only_model = remote_model("test-tool-mode-code-mode-only");
+    code_mode_only_model.tool_mode = Some(ToolMode::CodeModeOnly);
+    let code_mode_only_tools = tools_for_remote_model(code_mode_only_model, |_| {}).await?;
+    assert_eq!(
+        code_mode_only_tools,
+        vec![
+            codex_code_mode::PUBLIC_TOOL_NAME.to_string(),
+            codex_code_mode::WAIT_TOOL_NAME.to_string(),
+        ]
+    );
+
+    Ok(())
+}