Use model-specific auto-review outcome instructions (#39741)

## What changed

- Add `rejection_instructions` and `timeout_instructions` to catalog-provided auto-review messages.
- Use the acting model's instructions for denied and timed-out reviews across tool approvals, shell escalation, and MCP elicitation responses.
- Fall back to the existing instructions only when a catalog value is absent, while preserving explicit empty-string overrides.

## Testing

- Cover catalog overrides, legacy fallbacks, empty values, and separation between acting-model and reviewer-model messages.

GitOrigin-RevId: c5b2c2dbdaefd45d1d658651dd1abaeb6d8c93da

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

@@ -29,6 +29,7 @@ use codex_protocol::mcp_approval_meta::TOOL_DESCRIPTION_KEY as MCP_ELICITATION_T
 use codex_protocol::mcp_approval_meta::TOOL_NAME_KEY as MCP_ELICITATION_TOOL_NAME_KEY;
 use codex_protocol::mcp_approval_meta::TOOL_PARAMS_KEY as MCP_ELICITATION_TOOL_PARAMS_KEY;
 use codex_protocol::mcp_approval_meta::TOOL_TITLE_KEY as MCP_ELICITATION_TOOL_TITLE_KEY;
+use codex_protocol::openai_models::ModelInfo;
 use codex_rmcp_client::Elicitation;
 use rmcp::model::ElicitationAction;
 use rmcp::model::RequestMetaObject;
@@ -784,8 +785,9 @@ async fn review_guardian_mcp_elicitation(
         )
         .await;
 
-        return Ok(matches!(decision, ReviewDecision::Approved)
-            .then(|| mcp_elicitation_response_from_guardian_decision(decision)));
+        return Ok(matches!(decision, ReviewDecision::Approved).then(|| {
+            mcp_elicitation_response_from_guardian_decision(decision, &turn_context.model_info)
+        }));
     }
 
     let approval_policy = mcp_config.approval_policy.value();
@@ -855,6 +857,7 @@ async fn review_guardian_mcp_elicitation(
     .await;
     Ok(Some(mcp_elicitation_response_from_guardian_decision(
         decision,
+        &turn_context.model_info,
     )))
 }
 
@@ -1005,6 +1008,7 @@ fn mcp_elicitation_request_id(id: &RequestId) -> String {
 
 fn mcp_elicitation_response_from_guardian_decision(
     decision: ReviewDecision,
+    model_info: &ModelInfo,
 ) -> ElicitationResponse {
     match decision {
         ReviewDecision::Approved
@@ -1017,9 +1021,9 @@ fn mcp_elicitation_response_from_guardian_decision(
             meta: Some(mcp_elicitation_auto_meta()),
         },
         ReviewDecision::Denied { rejection } => mcp_elicitation_decline_with_message(rejection),
-        ReviewDecision::TimedOut => {
-            mcp_elicitation_decline_with_message(crate::guardian::guardian_timeout_message())
-        }
+        ReviewDecision::TimedOut => mcp_elicitation_decline_with_message(
+            crate::guardian::guardian_timeout_message(model_info),
+        ),
         ReviewDecision::Abort => ElicitationResponse {
             action: ElicitationAction::Cancel,
             content: None,

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

@@ -217,8 +217,9 @@ fn guardian_elicitation_review_request_declines_unsupported_opt_in_shapes() {
 
 #[test]
 fn guardian_decisions_map_to_elicitation_responses_without_session_state() {
+    let model = codex_models_manager::model_info::model_info_from_slug("acting-model");
     assert_eq!(
-        mcp_elicitation_response_from_guardian_decision(ReviewDecision::Approved),
+        mcp_elicitation_response_from_guardian_decision(ReviewDecision::Approved, &model),
         ElicitationResponse {
             action: ElicitationAction::Accept,
             content: Some(json!({})),
@@ -228,9 +229,10 @@ fn guardian_decisions_map_to_elicitation_responses_without_session_state() {
         }
     );
     assert_eq!(
-        mcp_elicitation_response_from_guardian_decision(ReviewDecision::denied(
-            "Denied by Guardian",
-        )),
+        mcp_elicitation_response_from_guardian_decision(
+            ReviewDecision::denied("Denied by Guardian"),
+            &model,
+        ),
         ElicitationResponse {
             action: ElicitationAction::Decline,
             content: None,
@@ -241,18 +243,18 @@ fn guardian_decisions_map_to_elicitation_responses_without_session_state() {
         }
     );
     assert_eq!(
-        mcp_elicitation_response_from_guardian_decision(ReviewDecision::TimedOut),
+        mcp_elicitation_response_from_guardian_decision(ReviewDecision::TimedOut, &model),
         ElicitationResponse {
             action: ElicitationAction::Decline,
             content: None,
             meta: Some(json!({
                 "approvals_reviewer": ApprovalsReviewer::AutoReview,
-                "message": crate::guardian::guardian_timeout_message(),
+                "message": crate::guardian::guardian_timeout_message(&model),
             })),
         }
     );
     assert_eq!(
-        mcp_elicitation_response_from_guardian_decision(ReviewDecision::Abort),
+        mcp_elicitation_response_from_guardian_decision(ReviewDecision::Abort, &model),
         ElicitationResponse {
             action: ElicitationAction::Cancel,
             content: None,
@@ -262,3 +264,29 @@ fn guardian_decisions_map_to_elicitation_responses_without_session_state() {
         }
     );
 }
+
+#[test]
+fn guardian_elicitation_timeout_uses_acting_model_instructions() {
+    let mut model = codex_models_manager::model_info::model_info_from_slug("acting-model");
+    for timeout_instructions in ["Catalog timeout instructions.", ""] {
+        model.model_messages = Some(
+            serde_json::from_value(json!({
+                "auto_review": {
+                    "timeout_instructions": timeout_instructions,
+                },
+            }))
+            .expect("model messages should deserialize"),
+        );
+        assert_eq!(
+            mcp_elicitation_response_from_guardian_decision(ReviewDecision::TimedOut, &model),
+            ElicitationResponse {
+                action: ElicitationAction::Decline,
+                content: None,
+                meta: Some(json!({
+                    "approvals_reviewer": ApprovalsReviewer::AutoReview,
+                    "message": timeout_instructions,
+                })),
+            }
+        );
+    }
+}