codex: address PR review feedback (#25032)

codex-rs/core/src/session/mod.rs

@@ -97,6 +97,7 @@ use codex_protocol::models::SandboxEnforcement;
 use codex_protocol::models::format_allow_prefixes;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelPreset;
+use codex_protocol::openai_models::MultiAgentVersion;
 use codex_protocol::permissions::FileSystemSandboxPolicy;
 use codex_protocol::permissions::NetworkSandboxPolicy;
 use codex_protocol::protocol::AdditionalContextEntry;
@@ -1650,7 +1651,7 @@ impl Session {
         turn_context: &TurnContext,
         msg: &EventMsg,
     ) {
-        if !self.enabled(Feature::MultiAgentV2) {
+        if turn_context.multi_agent_version != Some(MultiAgentVersion::V2) {
             return;
         }
 

codex-rs/core/src/session/multi_agents.rs

@@ -1,5 +1,5 @@
 use crate::session::turn_context::TurnContext;
-use codex_features::Feature;
+use codex_protocol::openai_models::MultiAgentVersion;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::SubAgentSource;
 
@@ -7,7 +7,7 @@ pub(super) fn usage_hint_text<'a>(
     turn_context: &'a TurnContext,
     session_source: &SessionSource,
 ) -> Option<&'a str> {
-    if !turn_context.features.enabled(Feature::MultiAgentV2) {
+    if turn_context.multi_agent_version != Some(MultiAgentVersion::V2) {
         return None;
     }
 

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

@@ -230,6 +230,8 @@ async fn remote_multi_agent_version_selector_overrides_feature_flags() -> Result
             .features
             .enable(Feature::MultiAgentV2)
             .expect("test config should allow feature update");
+        config.multi_agent_v2.root_agent_usage_hint_text =
+            Some("V2 guidance must not reach v1 models.".to_string());
     })
     .await?;
     assert_eq!(
@@ -246,6 +248,12 @@ async fn remote_multi_agent_version_selector_overrides_feature_flags() -> Result
         selected_tool_names(&v1_body, &["send_message", "followup_task", "list_agents"]),
         Vec::<String>::new()
     );
+    assert!(
+        !v1_body
+            .to_string()
+            .contains("V2 guidance must not reach v1 models."),
+        "v1 models should not receive v2 usage hints: {v1_body:?}"
+    );
 
     let mut v2_model = remote_model("test-multi-agent-v2");
     v2_model.multi_agent_version = Some(MultiAgentVersion::V2);
@@ -259,6 +267,8 @@ async fn remote_multi_agent_version_selector_overrides_feature_flags() -> Result
             .disable(Feature::MultiAgentV2)
             .expect("test config should allow feature update");
         config.multi_agent_v2.max_concurrent_threads_per_session = 17;
+        config.multi_agent_v2.root_agent_usage_hint_text =
+            Some("V2 guidance should reach v2 models.".to_string());
     })
     .await?;
     assert_eq!(
@@ -292,6 +302,12 @@ async fn remote_multi_agent_version_selector_overrides_feature_flags() -> Result
         ),
         "v2 spawn_agent should advertise the configured concurrency cap: {v2_body:?}"
     );
+    assert!(
+        v2_body
+            .to_string()
+            .contains("V2 guidance should reach v2 models."),
+        "v2 models should receive v2 usage hints: {v2_body:?}"
+    );
 
     Ok(())
 }