Log Guardian V2 classification results (#40028)

## What changed

- Emit a structured log event for each completed Guardian V2 classification with its thread, turn, tool call, risk score, review threshold, sample time, and whether the score was accepted or superseded.
- Verify that accepted async classification events appear in the reviewed thread's log export with the expected context and decision fields.

GitOrigin-RevId: a027d5991b12a1968b9327da57e2993f0a529ca1

codex-rs/Cargo.lock

@@ -3320,6 +3320,7 @@ dependencies = [
  "serde_json",
  "thiserror 2.0.18",
  "tokio",
+ "tracing",
 ]
 
 [[package]]

codex-rs/app-server/tests/suite/v2/guardian_v2.rs

@@ -33,6 +33,8 @@ use codex_app_server_protocol::TurnStartParams;
 use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::UserInput;
 use codex_features::Feature;
+use codex_state::StateRuntime;
+use codex_utils_absolute_path::test_support::PathExt;
 use core_test_support::responses;
 use core_test_support::skip_if_no_network;
 use pretty_assertions::assert_eq;
@@ -623,6 +625,43 @@ async fn guardian_v2_routes_tool_approvals(
         );
     }
 
+    if matches!(requirement, ModelReviewRequirement::Optional) {
+        let state_db = StateRuntime::init(
+            codex_state::SqliteConfig::new_for_testing(codex_home.path().abs()),
+            "mock_provider".to_owned(),
+        )
+        .await?;
+        // Exercise the same log export used by feedback/upload, including async
+        // classifier events that cannot rely on inheriting a thread tracing span.
+        let logs = timeout(TIMEOUT, async {
+            loop {
+                let logs = String::from_utf8(
+                    state_db
+                        .query_feedback_logs_for_threads(&[&reviewed_thread_id])
+                        .await?,
+                )?;
+                if logs.contains("Guardian V2 classification result") {
+                    return anyhow::Ok(logs);
+                }
+                tokio::time::sleep(Duration::from_millis(25)).await;
+            }
+        })
+        .await??;
+        let expected = [
+            "Guardian V2 classification result".to_owned(),
+            "call_id=guardian-action-0".into(),
+            format!("thread_id={reviewed_thread_id}"),
+            format!("action_risk={luna_score}"),
+            "review_threshold=0.5".into(),
+            "accepted=true".into(),
+        ];
+        assert!(
+            logs.lines()
+                .any(|line| expected.iter().all(|field| line.contains(field))),
+            "missing feedback log with fields: {expected:?}"
+        );
+    }
+
     if matches!(
         lifecycle,
         ThreadLifecycle::RootRollback

codex-rs/ext/guardian-v2/Cargo.toml

@@ -25,6 +25,7 @@ http = { workspace = true }
 serde_json = { workspace = true }
 thiserror = { workspace = true }
 tokio = { workspace = true, features = ["time"] }
+tracing = { workspace = true }
 
 [dev-dependencies]
 anyhow = { workspace = true }

codex-rs/ext/guardian-v2/src/async_scorer/extension.rs

@@ -566,6 +566,7 @@ impl GuardianV2Extension {
             );
             return;
         }
+        let call_id = input.call_id.to_owned();
         let action = GuardianAction {
             tool_name: input.tool_name.clone(),
             payload: input.payload.clone(),
@@ -741,12 +742,24 @@ impl GuardianV2Extension {
                     scores,
                     sampled_at: Some(sampled_at.into()),
                 };
-                if !thread
-                    .thread_extension_data()
-                    .insert_if(score.clone(), |previous| {
-                        previous.is_none_or(|previous| previous.sampled_at < score.sampled_at)
-                    })
-                {
+                let accepted =
+                    thread
+                        .thread_extension_data()
+                        .insert_if(score.clone(), |previous| {
+                            previous.is_none_or(|previous| previous.sampled_at < score.sampled_at)
+                        });
+                tracing::info!(
+                    %thread_id,
+                    %turn_id,
+                    %call_id,
+                    tool_call_index,
+                    action_risk = score.scores.get("action_risk").copied(),
+                    review_threshold = guardian_config.review_threshold,
+                    sampled_at = ?score.sampled_at,
+                    accepted,
+                    "Guardian V2 classification result"
+                );
+                if !accepted {
                     return Ok("superseded");
                 }
                 score_progress