Set verbosity to low for 5.1 (#6568)

And improve test coverage

codex-rs/core/tests/common/test_codex.rs

@@ -11,6 +11,7 @@ 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;
@@ -41,6 +42,14 @@ impl TestCodexBuilder {
         self
     }
 
+    pub fn with_model(self, model: &str) -> Self {
+        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");
+        })
+    }
+
     pub async fn build(&mut self, server: &wiremock::MockServer) -> anyhow::Result<TestCodex> {
         let home = Arc::new(TempDir::new()?);
         self.build_with_home(server, home, None).await

codex-rs/core/tests/suite/client.rs

@@ -21,6 +21,7 @@ use codex_core::protocol::Op;
 use codex_core::protocol::SessionSource;
 use codex_otel::otel_event_manager::OtelEventManager;
 use codex_protocol::ConversationId;
+use codex_protocol::config_types::Verbosity;
 use codex_protocol::models::ReasoningItemContent;
 use codex_protocol::models::ReasoningItemReasoningSummary;
 use codex_protocol::models::WebSearchAction;
@@ -624,6 +625,122 @@ async fn includes_user_instructions_message_in_request() {
     assert_message_ends_with(&request_body["input"][1], "</environment_context>");
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn includes_default_verbosity_in_request() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+    let server = MockServer::start().await;
+
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
+    let TestCodex { codex, .. } = test_codex().with_model("gpt-5.1").build(&server).await?;
+
+    codex
+        .submit(Op::UserInput {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+            }],
+        })
+        .await
+        .unwrap();
+
+    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
+
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
+
+    assert_eq!(
+        request_body
+            .get("text")
+            .and_then(|t| t.get("verbosity"))
+            .and_then(|v| v.as_str()),
+        Some("low")
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn configured_verbosity_not_sent_for_models_without_support() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+    let server = MockServer::start().await;
+
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
+    let TestCodex { codex, .. } = test_codex()
+        .with_model("gpt-5-codex")
+        .with_config(|config| {
+            config.model_verbosity = Some(Verbosity::High);
+        })
+        .build(&server)
+        .await?;
+
+    codex
+        .submit(Op::UserInput {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+            }],
+        })
+        .await
+        .unwrap();
+
+    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
+
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
+
+    assert!(
+        request_body
+            .get("text")
+            .and_then(|t| t.get("verbosity"))
+            .is_none()
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn configured_verbosity_is_sent() -> anyhow::Result<()> {
+    skip_if_no_network!(Ok(()));
+    let server = MockServer::start().await;
+
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
+    let TestCodex { codex, .. } = test_codex()
+        .with_model("gpt-5")
+        .with_config(|config| {
+            config.model_verbosity = Some(Verbosity::High);
+        })
+        .build(&server)
+        .await?;
+
+    codex
+        .submit(Op::UserInput {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+            }],
+        })
+        .await
+        .unwrap();
+
+    wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
+
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
+
+    assert_eq!(
+        request_body
+            .get("text")
+            .and_then(|t| t.get("verbosity"))
+            .and_then(|v| v.as_str()),
+        Some("high")
+    );
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn includes_developer_instructions_message_in_request() {
     skip_if_no_network!();