diff --git a/protobuf_definitions/control.proto b/protobuf_definitions/control.proto
index 17f5b976..163f7f85 100644
--- a/protobuf_definitions/control.proto
+++ b/protobuf_definitions/control.proto
@@ -105,6 +105,17 @@ message AutoPilotHeaveCtrl {
   AutoPilotHeaveState state = 1; // State of the auto pilot heave controller-
 }
 
+// Issue a command to set the vision-based tracking mode.
+//
+// Setting a mode requires an actively tracked single-object-tracking (SOT)
+// target; the drone refuses to enable a mode otherwise. Setting a different
+// mode while one is active switches atomically. Sending a state with no
+// mode set disables vision tracking. An OrbitState with a zero rate is
+// rejected.
+message VisionTrackingCtrl {
+  VisionTrackingState state = 1; // The desired vision tracking mode, or none to disable.
+}
+
 // Issue a command to start and pause the loaded mission.
 message RunMissionCtrl {
 }
diff --git a/protobuf_definitions/message_formats.proto b/protobuf_definitions/message_formats.proto
index d11bb9e1..d29405c5 100644
--- a/protobuf_definitions/message_formats.proto
+++ b/protobuf_definitions/message_formats.proto
@@ -178,6 +178,43 @@ message AutoPilotHeaveState {
   bool enabled = 1; // If auto pilot heave is enabled.
 }
 
+// Spotlight mode parameters.
+//
+// Vision-based mode that keeps the tracked object centred in the frame
+// (auto heading and vertical centring) while the pilot retains manual
+// surge and sway control. Currently carries no parameters.
+message SpotlightState {
+}
+
+// Active track mode parameters.
+//
+// Vision-based mode that keeps the tracked object centred in the frame and
+// automatically controls surge to maintain the desired distance to it.
+// Currently carries no parameters.
+message ActiveTrackState {
+}
+
+// Orbit mode parameters.
+//
+// Vision-based mode that keeps the tracked object centred in the frame while
+// the drone circles it laterally at the commanded angular rate.
+message OrbitState {
+  float rate = 1; // Orbit angular rate (deg/s); positive orbits clockwise seen from above. Must be non-zero.
+}
+
+// The active vision-based tracking mode.
+//
+// The modes are mutually exclusive, which the oneof encodes: at most one
+// mode is set at a time, and no field set means no vision tracking mode
+// is active.
+message VisionTrackingState {
+  oneof mode {
+    SpotlightState spotlight = 1; // Spotlight mode is active.
+    ActiveTrackState active_track = 2; // Active track mode is active.
+    OrbitState orbit = 3; // Orbit mode is active, at the reported angular rate.
+  }
+}
+
 // Control mode from drone supervisor
 message ControlMode {
   bool auto_depth = 1; // If auto depth is enabled.
@@ -187,6 +224,7 @@ message ControlMode {
   bool weather_vaning = 5; // If weather vaning is enabled.
   bool auto_pilot_surge_yaw = 6; // If auto pilot surge yaw is enabled.
   bool auto_pilot_heave = 7; // If auto pilot heave is enabled.
+  VisionTrackingState vision_tracking = 8; // The active vision-based tracking mode, if any.
 }
 
 // Tilt stabilization state.
@@ -1682,6 +1720,9 @@ message OperatorInfo {
 }
 
 // Single-object tracking (SOT) state reported by the computer vision pipeline.
+//
+// The velocity fields are Kalman filter estimates expressed in the CV frame
+// coordinate space (image_width x image_height pixels).
 message SotState {
   // Current state of the SOT tracker.
   enum State {
@@ -1694,6 +1735,11 @@ message SotState {
   BoundingBox bounding_box = 2; // Current tracked bounding box (valid when TRACKING).
   uint32 image_width = 3; // Width of the source frame in pixels.
   uint32 image_height = 4; // Height of the source frame in pixels.
+  float confidence = 5; // Tracker confidence of the last model update (0..1). 0 while coasting and when LOST.
+  float vx = 6; // Kalman velocity estimate of the bounding box centre, horizontal (px/s).
+  float vy = 7; // Kalman velocity estimate of the bounding box centre, vertical (px/s).
+  float vs = 8; // Kalman rate of change of the bounding box area, width * height (px²/s).
+  float vr = 9; // Kalman rate of change of the bounding box aspect ratio, width / height (1/s).
 }
 
 // Origin of an annotation. Mirrors the AnnotationSource enum in Blueye Cloud.