diff --git a/plugins/ai_face_recog/ai_face_recog_node.cpp b/plugins/ai_face_recog/ai_face_recog_node.cpp
index 7767b08..c40c7d0 100644
--- a/plugins/ai_face_recog/ai_face_recog_node.cpp
+++ b/plugins/ai_face_recog/ai_face_recog_node.cpp
@@ -63,16 +63,32 @@ inline bool IsPersonDetection(const Detection& det, int person_class_id) {
     return det.cls_id == person_class_id;
 }
 
-int AssociateFaceToPersonTrack(const Rect& face_bbox, const std::vector<Detection>& dets, int person_class_id) {
+struct FaceTrackAssociationDiag {
+    int total_dets = 0;
+    int person_dets = 0;
+    int tracked_person_dets = 0;
+    int containing_tracked_person_dets = 0;
+    int best_track_id = -1;
+    float best_overlap = -1.0f;
+};
+
+int AssociateFaceToPersonTrack(const Rect& face_bbox, const std::vector<Detection>& dets, int person_class_id,
+                               FaceTrackAssociationDiag* diag = nullptr) {
     const float center_x = face_bbox.x + face_bbox.w * 0.5f;
     const float center_y = face_bbox.y + face_bbox.h * 0.5f;
 
+    if (diag) *diag = FaceTrackAssociationDiag{};
+    if (diag) diag->total_dets = static_cast<int>(dets.size());
+
     int best_track_id = -1;
     float best_overlap = -1.0f;
     for (const auto& det : dets) {
+        if (diag && IsPersonDetection(det, person_class_id)) ++diag->person_dets;
         if (!IsPersonDetection(det, person_class_id)) continue;
         if (det.track_id < 0) continue;
+        if (diag) ++diag->tracked_person_dets;
         if (!ContainsPoint(det.bbox, center_x, center_y)) continue;
+        if (diag) ++diag->containing_tracked_person_dets;
 
         const float overlap = IntersectionArea(face_bbox, det.bbox);
         if (overlap > best_overlap) {
@@ -81,9 +97,34 @@ int AssociateFaceToPersonTrack(const Rect& face_bbox, const std::vector<Detectio
         }
     }
 
+    if (diag) {
+        diag->best_track_id = best_track_id;
+        diag->best_overlap = best_overlap;
+    }
     return best_track_id;
 }
 
+std::string BuildFaceTrackAssociationDiagLine(const std::string& node_id, uint64_t frame_id, const Rect& face_bbox,
+                                              int person_class_id, const FaceTrackAssociationDiag& diag) {
+    std::ostringstream oss;
+    oss << "[ai_face_recog] track_assoc"
+        << " id=" << node_id
+        << " frame=" << frame_id
+        << " person_class_id=" << person_class_id
+        << " face_bbox=(" << static_cast<int>(std::lround(face_bbox.x))
+        << "," << static_cast<int>(std::lround(face_bbox.y))
+        << "," << static_cast<int>(std::lround(face_bbox.w))
+        << "," << static_cast<int>(std::lround(face_bbox.h))
+        << ")"
+        << " dets=" << diag.total_dets
+        << " person_dets=" << diag.person_dets
+        << " tracked_person_dets=" << diag.tracked_person_dets
+        << " containing_tracked_person_dets=" << diag.containing_tracked_person_dets
+        << " best_track_id=" << diag.best_track_id
+        << " best_overlap=" << std::fixed << std::setprecision(1) << diag.best_overlap;
+    return oss.str();
+}
+
 struct GalleryEntry {
     int person_id = -1;
     std::string name;
@@ -924,6 +965,7 @@ private:
 
         for (int i = 0; i < limit; ++i) {
             const FaceDetItem& face = frame->face_det->faces[static_cast<size_t>(i)];
+            FaceTrackAssociationDiag assoc_diag;
 
             face_buf_.resize(static_cast<size_t>(model_w_) * static_cast<size_t>(model_h_) * 3);
             if (cfg->align && face.has_landmarks && model_w_ == 112 && model_h_ == 112) {
@@ -1001,7 +1043,7 @@ private:
             FaceRecogItem item;
             item.bbox = face.bbox;
             item.person_track_id = frame->det
-                ? AssociateFaceToPersonTrack(face.bbox, frame->det->items, cfg->person_class_id)
+                ? AssociateFaceToPersonTrack(face.bbox, frame->det->items, cfg->person_class_id, &assoc_diag)
                 : -1;
             item.has_landmarks = face.has_landmarks;
             item.landmarks = face.landmarks;
@@ -1016,6 +1058,11 @@ private:
 
             if (cfg->emit_embedding) item.embedding = emb;
             rr.items.push_back(std::move(item));
+
+            if (cfg->debug.enabled && cfg->debug.log_matches) {
+                LogInfo(BuildFaceTrackAssociationDiagLine(id_, frame->frame_id, face.bbox,
+                                                          cfg->person_class_id, assoc_diag));
+            }
         }
 
         if (sync_src) frame->SyncEnd();